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The use of red fluorescent powder derived from nitrides and oxides in warm white LEDs is a pressing concern due to its lower quantum efficiency. Fluoride red phosphors activated by Mn4+ ions show promising potential for application in white light-emitting diodes (LEDs) due to their distinctive narrowband red emission and broad blue excitation, along with the relatively mild synthesis conditions required. However, the quantum efficiency of early Mn4+-doped fluoride phosphors was not optimal, highlighting the importance of identifying a suitable preparation method and matrix. Here, we introduce an efficient and thermally stable red fluoride phosphor, Cs 2 SiF 6 :Mn4+, which demonstrates a remarkable quantum efficiency of 98.32 % achieved through ion exchange techniques. However, even at a temperature of 423 K, the luminous intensity still maintained at 95 % of that under room temperature conditions. By incorporating Cs 2 SiF 6 :Mn4+ as a red emitter, a stable 10 W high-power warm white LEDs with a luminous efficiency of approximately 126.1 lm/W can be realized. These findings underscore the significant potential of the red phosphor Cs 2 SiF 6 :Mn4+ in advancing high-performance, high-power warm white LEDs. [ABSTRACT FROM AUTHOR]

In this article, zinc-borosilicate silicon（ZBS） glass containing europium (Eu) ions and CsPbBr 3 quantum dots (QDs) (ZEQ) was synthesized via melting crystallization route. The composition and luminescent properties are investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and photoluminescence (PL) spectra. The XRD and XPS results imply that Eu 3+, Eu 2+ ions and CsPbBr 3 QDs are coexisted in ZBS glass. The dual-mode emission from cyan to orange-red can be achieved by adjusting the melting temperature. Besides, the ZEQ has good water resistance, outstanding light irradiation and excellent heating-cooling cycle stability. Moreover, based on the ZEQ, the light-emitting diodes (LEDs) are designed to obtain the white light with the correlated color temperature (CCT) of 5255 K, the Coherent Infrared Energy (CIE) color coordinate of (0.337 0.313), the NSCT color gamut of 116 % and 87 % of Rec.2020. Thus, this article provides a novel material ZEQ, which is tunable luminescence and ultra-stable. The strategy provides the route that the luminescence of Eu ions and QDs can be observed at the same time, solving the difficulty of the rare earth ions entering into the QDs lattice. Moreover, the ZEQ is expected to be used as the light source for solid-state lighting and also provides valuable research results for future exploration of functional glass containing both rare-earth ions and QDs materials. [ABSTRACT FROM AUTHOR]

Herein, a variety of single-phase full-spectrum emission phosphors doped with Eu2+ were synthesized. Under the 350 nm excitation, as K+ and Y3+ were introduced into Ca 10 Na(PO 4) 7 (CNP):1.5%Eu2+, respectively, the emission color of Ca 9.85 K y Na (1- y) (PO 4) 7 :1.5%Eu2+ (0 ≤ y ≤ 1.0) was tuned from yellow to cyan, while that of Ca (9.85- z) NaY 0.667 z (PO 4) 7 :1.5%Eu2+ (0 ≤ z ≤ 1.0) was tuned from yellow to green. The internal quantum yield (QY) of Ca 9·85 K 0·4 Na 0·6 (PO 4) 7 (CKNP):1.5%Eu2+ and Ca 9·45 NaY 0·267 (PO 4) 7 (CNYP):1.5%Eu2+ reached 47.47 % and 27.11 %, respectively. The introduction of K+ or Y3+ made Eu2+ selectively occupy the Ca sites and led to changes in the local environment of Eu2+, allowing for spectral tuning emission. In addition, the luminescence intensity of the samples retained 54.59 % and 31.34 % of their room temperature values. Eventually, two white light emitting diode (WLED) devices were fabricated, combining the synthesized white emitting phosphors with 365 nm ultraviolet (UV) chips. They exhibited high color rendering indices of 84.7 and 77.0, along with low correlated color temperatures of 5435 K and 5023 K. The Commission Internationale de L'Eclairage (CIE) color coordinates were (0.3349, 0.3975) and (0.3517, 0.4366), respectively. The results pointed to the phosphors' potential suitability for use in the WLED sector. [ABSTRACT FROM AUTHOR]

The eyes play a special role in human communications. Previous psychological studies have reported reflexive attention orienting in response to another individual's eyes during live interactions. Although robots are expected to collaborate with humans in various social situations, it remains unclear whether robot eyes have the potential to trigger attention orienting similarly to human eyes, specifically based on mental attribution. We investigated this issue in a series of experiments using a live gaze-cueing paradigm with an android. In Experiment 1, the non-predictive cue was the eyes and head of an android placed in front of human participants. Light-emitting diodes in the periphery served as target signals. The reaction times (RTs) required to localize the valid cued targets were faster than those for invalid cued targets for both types of cues. In Experiment 2, the gaze direction of the android eyes changed before the peripheral target lights appeared with or without barriers that made the targets non-visible, such that the android did not attend to them. The RTs were faster for validly cued targets only when there were no barriers. In Experiment 3, the targets were changed from lights to sounds, which the android could attend to even in the presence of barriers. The RTs to the target sounds were faster with valid cues, irrespective of the presence of barriers. These results suggest that android eyes may automatically induce attention orienting in humans based on mental state attribution. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary The use of chemical plant protection products must be reduced to promote sustainability in food production. One possible alternative is biological control agents (BCAs), but their efficacy under commercial conditions does not always reach the standard of chemical control agents. Previously, light has been found to induce mechanisms in bacterial BCAs that can affect their distribution and establishment. This could promote BCA efficacy. We looked into how monochromatic and polychromatic (which is what growers use) light treatments affected the occurrence of three BCAs post‐application. By combining two non‐chemical methods: a biological (BCA) and a cultural (light) control method, this offers a new integrated pest control strategy. The dynamics and functionality of beneficial and non‐beneficial, non‐phototrophic bacteria can be influenced by light quality. We investigated if light could aid the survival of three bacterial biological control agents (BCAs; Bacillus amyloliquefaciens DSM7, Pseudomonas chlororaphis 50083 and Streptomyces griseoviridis CBS904.68) in the canopy of greenhouse‐grown tomatoes at four light treatments. Tomato plants were exposed to 50 μmol m−2 s−1 of either polychromatic light (white) or monochromatic light (blue: 420 nm, green: 530 nm and red: 660 nm) using DYNA LED lamps for a total of 48 h post foliar application of the BCAs. Leaves were harvested from two levels in the canopy at the top and middle of each plant at 0, 2, 4, 8, 12, 24 and 48 h post inoculation. The occurrences of the BCAs were quantified by plate count and droplet digital PCR (ddPCR). S. griseoviridis persisted under most treatments, whereas P. chlororaphis and B. amyloliquefaciens preferred the polychromatic and green light treatments as depicted by the viable count analyses. Significant differences between the DNA and cDNA concentrations were only noted for P. chlororaphis, with prominent wavelength effects. Light exposure dose, placement in the canopy and wavelength were found to be decisive factors for BCA re‐isolation, indicating that they have different optimal light environments. [ABSTRACT FROM AUTHOR]

Few-layered N -doped rGO nanosheets covered with defective TiO 2- x nanoparticles form an enriched 2D/0D Schottky heterojunction through interfacial N -Ti and C-Ti bonds, serving as a bipolar cathode host for lithium-sulfur batteries with enhanced electrochemical properties. [Display omitted] The shuttling and sluggish conversion kinetics of lithium polysulfides (LiPSs) lead to poor cycling performance and low energy efficiency in lithium-sulfur batteries (LSBs). In this work, a hierarchically structured nanocomposite, synthesized through a surfactant-directed hydrothermal growth following dopamine-protected pyrolysis, serves as a bidirectional catalyst for LSBs. This nanocomposite comprises N -doped reduced graphene oxide (rGO) nanosheets anchored with uniformly distributed TiO 2- x nanoparticles via interfacial N -Ti and C-Ti bonding, resulting in the formation of abundant 2D/0D Schottky heterojunctions (rGO/TiO 2- x). Density functional theory (DFT) calculations and in situ Raman characterizations demonstrate that rGO/TiO 2- x effectively inhibits the shuttling of LiPSs with enhanced redox kinetics, achieving high utilization of the sulfur cathode and improving the overall reversibility. A high areal capacity is attained at a high sulfur loading and a low electrolyte/sulfur ratio. The initial specific capacity reaches 1010 mA h g−1 at a current density of 0.2C (1C = 1675 mA g−1), and a retention of 86.4 % is attained over 100 cycles. A light-emitting diode (LED) screen using two LSBs with rGO/TiO 2- x demonstrates their high potential for practical applications. [ABSTRACT FROM AUTHOR]

Broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have become important as new NIR light sources in NIR spectroscopy and NIR imaging techniques. However, currently developed broadband NIR phosphors commonly suffer from weak emission and poor thermal stability. In this work, a series of Gd 3 Lu 2 Ga 3 O 12 : Cr3+ phosphors were synthesized via high-temperature solid-state reaction. Under 460 nm excitation, the phosphors exhibit an intense emission spanning from 650 to 1150 nm with a full width at half maximum (FWHM) of 122 nm. After introducing Yb3+ as a co-dopant, the emission of the phosphor has been broadened greatly. Interestingly, the studied phosphors demonstrate super high thermal stability in a wide temperature range of 35–560 K, with the integrated emission intensity fluctuating within 10 %. At 435 K, the emission intensity of Gd 3 Lu 2 Ga 3 O 12 : 0.03Cr3+ remains 99.5 % and Gd 3 Lu 2 Ga 3 O 12 : 0.03Cr3+, 0.01 Yb3+ keeps 102.7 % of the initial intensity at room temperature. These NIR phosphors have been encapsulated with a common commercial 460 nm blue LED chip to fabricate a pc-LED device. The NIR output power of the device reaches 23.93 mW@100 mA, with a photoelectric conversion efficiency of 9.81 % at 20 mA current. The applications of the prepared NIR light source in night vision, and bioimaging have been demonstrated. The results show that these Cr3+/Yb3+ doped garnet phosphors can be effectively used in NIR light sources. [ABSTRACT FROM AUTHOR]

Due to the adoption of fluorescent powder encapsulated by organic resin, commercial light emitting diodes (LEDs) suffer from low thermal stability and poor light quality under high temperature, and luminescent glass is one of the effective ways to solve this problem. A series of borosilicate (B 2 O 3 –SiO 2 –Al 2 O 3 –PbO-Dy 2 O 3 –Eu 2 O 3 , marked as BSAP: DyEu) was prepared by the gas suspension technique. The basic characterization test indicate that the prepared glass has excellent thermal stability and stable structure. The optical properties of the luminescent glass were investigated in detail. By changing the Eu3+ doping amount, the Dy3+/Eu3+ co-doped glass can realize warm white light emission. The temperature-variable fluorescence spectra of BASP: Dy1.25Eu1.0 were analyzed, and the glass can produce strong warm white light emission in a wide temperature range. At 700 K, the luminous intensity of the glass remains above 38.49 % of the room temperature, and the chroma shift ΔC = 8.57 × 10−3. In addition, the w- LED device based on commercial GaN chip and BSAP: DyEu glass realizes warm white light output with excellent correlated color temperature (3063 K) and high color rendering index (90.3). The analysis shows that Dy3+/Eu3+ co-doped borosilicate glass can be used as a candidate material for w- LED applications. [ABSTRACT FROM AUTHOR]

Mn4+ activated fluoride red phosphors are used in warm white light emitting diodes (WLEDs). However, their inherently low moisture resistance is a major barrier to their use in high humidity conditions. In this work, the Nb-based oxyfluoride phosphors A x NbOF y :Mn4+ (A = Na, Cs; x = 2, 3; y = 5, 6) were synthesized by the co-precipitation method. The crystal structure, morphology, and luminescence properties are investigated with composition variation. The non-equivalent replacement of Nd5+ ions by Mn4+ results in bright red emission under blue light excitation. These phosphors showed very good moisture resistant luminescence. The best performance was achieved by the Na 3 NbOF 6 :0.1%Mn4+, which retained 98 % of the initial fluorescence intensity after immersion in water for 60 min. In addition, the W6+ and Mo6+ are used to compensate for the charge difference between Mn4+ and Nd5+ in Na 3 NbOF 6 :Mn4+. The compensated phosphors have shown large enhancements of 169 % (W6+) and 168 % (Mo6+) in luminescence intensity. This strategy of non-equivalent doping approach of Mn4+ into the Nb-based oxyfluoride materials and the charge compensation by W6+/Mo6+ to enhance the luminescence intensity provides a new way to realize high performance red phosphors for WLEDs. [ABSTRACT FROM AUTHOR]

The utilization of perovskite quantum dots (PQDs) in photoelectric devices is indeed an area of intense research due to their advantageous properties such as tunability of visible light and efficient light emission. In this study, mixed CsPbI 3 and FAPbI 3 PQD dispersions were successfully employed for cation exchange to prepare red-color Cs 1−x FA x PbI 3 PQD with the photoluminescence (PL) wavelength from 689 nm (x = 0) to 778 nm (x = 1). It is also found that the aggregation of Cs 1−x FA x PbI 3 PQD films were strongly dependent on x. When x from 0 to 0.6, the holes in PQD thin films were gradually improved. On the opposite, when x > 0.6, the PQDs thin films returned more and more holes due to an excess of FA + cations. The resulting Cs 1-x FA x PbI 3 PQD based light-emitting diodes (LEDs) also demonstrated tunable emission wavelengths, and it is worth mentioning that the maximum external quantum efficiency (EQE) of 11.22 % was achieved with an emission wavelength of 758 nm when x = 0.6. [ABSTRACT FROM AUTHOR]

In recent decades, numerous red phosphors have been designed and developed. Nevertheless, many of them are unsatisfactory due to their low brightness and poor thermal stability. Look at these shortcomings; present study reports on Eu3+ doped Y 2 Si 2 O 7 (YPS) phosphors, synthesized through low temperature based urea assisted gel-combustion method. Comprehensive investigations were conducted on phase purity, luminous characteristics, energy transfer mechanism, quantum efficacy, morphology, elemental makeup, band gap and thermal stability. XRD analysis was employed to verify the preparation of Y 2 Si 2 O 7 matrix with triclinic structure (P-1 space group). Morphology and elemental investigations of the fabricated materials was evaluated via TEM and EDX techniques respectively. Under the illumination at 393 nm, the most strong emission band is shown in PL spectra at 613 nm (electric dipole 5D 0 →7F 2 transition). Additionally, the dipole-quadrupole (d-q) interaction was found to be the predominant route of energy transfer among nearby Eu3+ ions and it was concluded that 3 mol % was the optimal doping concentration of Eu3+ ions. The Judd-Ofelt (J-O) theory was used for current phosphors in order to establish their Ω 2 and Ω 4 with other radiative parameters. The assessment of thermal stability yielded highly promising results with activation energy of 0.241 eV. Present research indicates that Y 2 Si 2 O 7 :Eu3+ is a promising candidate of red emitting phosphor for white light-emitting diodes. [Display omitted] • Gel-combustion derived Eu3+ doped Y 2 Si 2 O 7 nanophosphors were crystallized into triclinic symmetry with P–1 space group. • Dominance of electric dipole 5D 0 →7F 2 transition at 613 nm was observed which define the red color of synthesized nanophosphors. • The luminous thermal stability revealed 69.4 % of luminescence at 498 K with activation energy of 0.241 eV. • Colorimetric investigation of the synthesized Y 2 Si 2 O 7 :Eu3+ nanophosphors validate their applicability in white light applications. [ABSTRACT FROM AUTHOR]

Integrating flexible electronics and photonics can create revolutionary technologies, but combining these components on a single polymer device has been difficult, particularly for high-volume manufacturing. Here, we present a robust chiplet-level heterogeneous integration of polymer-based circuits (CHIP), where ultrathin polymer electronic and optoelectronic chiplets are vertically bonded at room temperature and shaped into application-specific forms with monolithic Input/Output (I/O). This process was used to develop a flexible 3D integrated optrode with high-density microelectrodes for electrical recording, micro light-emitting diodes (μLEDs) for optogenetic stimulation, temperature sensors for bio-safe operations, and shielding designs to prevent optoelectronic artifacts. CHIP enables simple, high-yield, and scalable 3D integration, double-sided area utilization, and miniaturization of connection I/O. Systematic characterization demonstrated the scheme's success and also identified frequency-dependent origins of optoelectronic artifacts. We envision CHIP being applied to numerous polymer-based devices for a wide range of applications. [ABSTRACT FROM AUTHOR]

The two technologies of dye-sensitized solar cells (DSSCs) and organic light-emitting devices (OLEDs) are emerging in the development of new sources of energy and lighting, respectively. The exceptional features of these technologies, including their color, insensitivity to temperature, and high response angle, have caused their attention and development. Organic compounds play a key role in these two technologies and cause the effective response and stability of the device, so high stability, longevity, and the possibility of simple application in the structure of the structure are of great importance. Molecular engineering and the application of various substitutions to the naphthalimide core can produce promising results for the preparation of stable organic materials with diversity in properties. In this review, naphthalimides are introduced as an effective core in the preparation of lightand electricity-sensitive dyes. Its application in two technologies, DSSCs and OLED, is explained, and the different components of these technologies are briefly introduced. One of the highest efficiencies reported for dye-sensitized solar cells based on naphthalimide as photosensitizers is 10.8 %. This sensitizer has alkyl and indoline groups. Different structures of arrangement of electron donor and electron acceptor groups will be investigated and the performance efficiency of these devices will also be investigated. Studies show that the amino group is an important substitution in the preparation of naphthalamide fluorescent dyes. The presence of this group will increase the efficiency of the amplifier by up to 10 %. [ABSTRACT FROM AUTHOR]

Organic–inorganic metal halides have recently garnered significant interest owing to their excellent photoluminescence performance and high stability. Therefore, a synthetic procedure was designed here to obtain (PPZ)ZnBr4 (PPZ = 1-phenylpiperazine) nanocrystals (NCs) incorporating Pb2+ and Sn2+ ions, obtaining blue and orange light emitters, respectively. Photoluminescence quantum yields of blue and orange emissions were up to 43.2% and 29.9%, respectively, under 365-nm excitation. The prepared NCs also demonstrated long-term stability and humidity resistance. This study not only provided a deep comprehension of low-dimensional perovskites, but also established an avenue for the strategic design of high-performance light-emitting perovskites. [ABSTRACT FROM AUTHOR]

Background: The present study aimed to investigate the impact of the light-emitting diode (LED) green light alone or in combination with melatonin on pecking-related hormone regulation during incubation under normal and under hormonal stress conditions in breeder eggs. This study was divided into 2 experiments: In the first experiment effect of LED green light incubation on pecking-related hormones under normal conditions, on Hy-line brown (low pecking phenotype) and Roman pink (high pecking phenotype) eggs were tested. The 296 eggs of each strain were divided into two groups: LED green light incubation and dark incubation (control), each containing four replicates (37 eggs/replicate). The second experiment was conducted to evaluate the effect of LED green light incubation alone or in combination with melatonin under hormonal stress conditions on Roman pink eggs. A total of 704 Roman pink eggs were taken and divided into four groups, each consisting of 176 eggs. Each group was further divided into 2 subgroups, LED green light-regulated incubation and dark incubation with 88 eggs per subgroup, having 4 replicates of 22 eggs each. The groups were as follows: corticosterone solution injection (CI), corticosterone + melatonin mixed solution injection (CMI), Phosphate buffer solution injection (PI), and no injection (UI). Results: Results of the first experiment revealed a higher level of serotonin hormone and lower corticosterone hormone in Hy-Line brown embryos compared to Roman pink embryos during dark incubation. The LED green light incubation significantly (P < 0.05) increased the level of 5-HT while decreasing the CORT level in Roman pink embryos indicating its regulatory effect on pecking-related hormones. Results of the second experiment showed that LED green light incubation significantly (P < 0.05) alleviated the CORT-induced hyperactivity of plasma 5-HT in Roman pink embryos. Furthermore, Melatonin (MLT) injection and LED green light together significantly (P < 0.05) reduced the hormonal stress caused by corticosterone injection in the eggs. Conclusions: Overall, the LED green light regulatory incubation demonstrated a regulatory effect on hormones that influence pecking habits. Additionally, when coupled with MLT injection, it synergistically mitigated hormonal stress in the embryos. So, LED green light incubation emerged as a novel method to reduce the damaging pecking habits of poultry birds. [ABSTRACT FROM AUTHOR]

Electrodeposited Invar alloy film is highly desirable for manufacturing fine metal masks (FMMs) used in Organic Light-Emitting Diodes (OLEDs). However, its development is limited by the high coefficient of thermal expansion (CTE). In this study, we successfully obtained a coarse-grained electrodeposited Invar alloy film with near-zero thermal expansion and inclusions smaller than 300 nm, achieved through abnormal grain growth (AGG) induced by second-phase particles. Our experiments confirmed that these second-phase particles are composed of (Fe, Ni)1-xS. During AGG, the aggregation and coarsening of these second-phase particles lead to changes in local strain energy, and the combined effects of surface and strain energies results in the rapid preferential growth of (110)-oriented grains. The matrix grains are engulfed by large-sized grains and transformed into sub-grains, which merge with the abnormally growing grains through grain rotation. An inverse relationship was found between CTE and grain size. Following vacuum annealing at 800 °C for 2 h and hydrogen annealing for 1 h, the average grain size increased to approximately 400 µm, while the CTE was reduced to 0.3 × 10–6/ °C. This study provides a new method for obtaining electrodeposited Invar alloy films that meet commercial applications criteria for and are suitable for FMM fabrication for high-definition OLEDs. [ABSTRACT FROM AUTHOR]

Although power conversion efficiency (PCE) of solar cells (SCs) continues to improve, they are still far from practical application because of their complex synthesis process, high cost and inferior operational stability. Carbon quantum dots with high material stability and remarkable photoluminescence are successfully used in light‐emitting diodes. A good light emitter should also be an efficient SC according to the photon balance in Shockley–Quieisser formulation, in which all excitons are ultimately separated. However, the finite quantum‐sized sp2 domain leads to tight exciton bonding, and highly delocalized electron clouds in irregular molecular stacks form disordered charge transfer, resulting in severe energy loss. Herein, an axially growing carbon quantum ribbon (AG‐CQR) with a wide optical absorption range of 440–850 nm is reported. Structural and computational studies reveal that AG‐CQRs (aspect ratio ≈2:1) with carbonyl groups at both ends regulate energy level and efficiently separate excitons. The stacking‐controlled two‐dimensional AG‐CQR film further directionally transfers electrons and holes, particularly in AB stacking mode. Using this film as active layer alone, the SCs yield a maximum PCE of 1.22%, impressive long‐term operational stability of 380 h, and repeatability. This study opens the door for the development of new‐generation carbon‐nanomaterial‐based SCs for practical applications. [ABSTRACT FROM AUTHOR]

Red emission is crucial for fabricating high-quality phosphor-converted light emitting-diode (LED) to satisfy its vivid applications. Herein, Lu 2(1- x) W 3 O 12 :2 x Eu3+ (Lu 2 W 3 O 12 :2 x Eu3+) red-emitting phosphors were developed through sol-gel reaction method. Through adding Eu3+, phase transition, from orthorhombic to monoclinic phase, happened in studied samples. Excited at 394 nm, the resulting phosphors emitted intense red emission and their intensities can be manipulated via phase transition. Specifically, the phase transition can delay concentration quenching in resultant phosphors, of which the optimal state was realized at x = 0.7, resulting in enhanced luminescence properties. Besides, the color purity and thermal stability of prepared phosphors can also be improved by means of phase transition. Based on Judd-Ofelt theory, the local symmetric performances of Eu3+ in synthesized phosphors were analyzed via calculating the corresponding Ω 2 values. Via using the designed phosphors as red-emitting components, different types of LED devices were packaged, i.e. red-emitting LED and white-LED. For red-emitting LEDs, their emission bands matched well with the absorption bands of plant pigments, allowing their applications in plant growth, which had been confirmed by rice growth experiments. Furthermore, the packaged white-LED can emit warm white light with high color rendering index and low correlated color temperature, which were slightly impacted by working current. Our finding revealed that phase transition was an efficient route to delay the concentration quenching effect and regulate the luminescence characterizations of Eu3+-activated phosphors. [ABSTRACT FROM AUTHOR]

Near infrared (NIR) phosphors have been booming as promising candidates for agriculture due to the adjustable spectrum and excellent match with the dyes of the plants. Here, Mn4+ activated double perovskite LaMg 2/3 Mn 1/3 O 3 NIR phosphor was prepared, which showed high match with the absorption spectra of phytochrome P FR. Concentration of Mg2+ was decreased to create octahedron vacancy into the lattice to improve the luminescence performance. Structure and luminescence variation of the phosphors LaMg 2/3- x Nb 1/3 O 3 :Mn4+ along with the increased vacancy concentration were carried out. Relative sensitivity S r of the optimized LaMg 0.57 Nb 0.33 O 3 :Mn4+ reaches 3.109 % and exhibits great application potential in temperature sensor. Both the NIR light emitting diode (LED) and white LED were fabricated by using this double perovskite NIR phosphor and applied to the cultivation of dragon fruit as light compensation. The dragon fruits matured faster than those without any light compensation. These results confirm the great application potential of this double perovskite NIR phosphor in temperature sensor and plant cultivation. [ABSTRACT FROM AUTHOR]

Minimizing the emission loss with rising temperature is important to fundamental research and technological applications of phosphor-converted white light-emitting diodes (pc-WLEDs). Red phosphor materials are crucial for improving the illumination and backlit display quality of pc-WLEDs. In this work, non-hygroscopic Al 2 (WO 4) 3 :0.05Eu3+,0.05 Tb3+ (AWO:0.05Eu,0.05 Tb) red phosphors with low positive thermal expansion are successfully developed to simultaneously achieve zero thermal quenching (ZTQ) and a highly efficient red emitting. Under the optimal 397 nm NUV light excitation, AWO:0.05Eu,0.05 Tb exhibited a strong red emission at 618 nm with a high color purity (CP) of 99.71 % and a high internal quantum efficiency (IQE) of 80.24 %. Furthermore, a warm pc-WLED device with suitable color coordinates (0.347, 0.317), high color rendering index (CRI = 90.2) and low color correlated temperature (CCT = 4737 K) was fabricated based on the as-prepared red phosphor AWO:0.05Eu,0.05 Tb. The findings suggest that the proposed phosphor holds significant promise as a red component for high-power warm pc-WLEDs, which may open up new ways for the exploration of high-performance lanthanide-activated red phosphors towards versatile applications. [ABSTRACT FROM AUTHOR]

The electron injection and transport behavior are of vital importance to the performance of quantum-dot light-emitting diodes. By simultaneously measuring the electroluminescence-photoluminescence of the quantum-dot light-emitting diodes, we identify the presence of leakage electrons which leads to the discrepancy of the electroluminescence and the photoluminescence roll-off. To trace the transport paths of the leakage electrons, a single photon counting technique is developed. This technique enables us to detect the weak photon signals and thus provides a means to visualize the electron transport paths at different voltages. The results show that, the electrons, except those recombining within the quantum-dots, leak to the hole transport layer or recombine at the hole transport layer/quantum-dot interface, thus leading to the reduction of efficiency. By reducing the amount of leakage electrons, quantum-dot light-emitting diode with an internal power conversion efficiency of over 98% can be achieved. Su et al. report a single photon counting technique to trace the electron transport paths at different voltages for QLEDs, revealing the leakage electrons into the hole transport layer or recombination at the interface, providing unambiguous understanding in the device operation and degradation mechanism. [ABSTRACT FROM AUTHOR]

Spin-polarized light-emitting diodes (spin-LEDs) convert the electronic spin information to photon circular polarization, offering potential applications including spin amplification, optical communications, and advanced imaging. The conventional control of the emitted light's circular polarization requires a change in the external magnetic field, limiting the operation conditions of spin-LEDs. Here, we demonstrate an atomically thin spin-LED device based on a heterostructure of a monolayer WSe2 and a few-layer antiferromagnetic CrI3, separated by a thin hBN tunneling barrier. The CrI3 and hBN layers polarize the spin of the injected carriers into the WSe2. With the valley optical selection rule in the monolayer WSe2, the electroluminescence exhibits a high degree of circular polarization that follows the CrI3 magnetic states. Importantly, we show an efficient electrical tuning, including a sign reversal, of the electroluminescent circular polarization by applying an electrostatic field due to the electrical tunability of the few-layer CrI3 magnetization. Our results establish a platform to achieve on-demand operation of nanoscale spin-LED and electrical control of helicity for device applications. Spin-polarized light-emitting diodes (spin-LEDs) convert the electronic spin information to photon circular polarization, but they are usually controlled only by external magnetic fields. Here, the authors report the realization of spin-LEDs based on 2D CrI3/hBN/WSe2 heterostructures, showing electrical tunability of the electroluminescence helicity. [ABSTRACT FROM AUTHOR]

The effects of various additives (Y2O3, Ga2O3, and WO3) on photocatalytic degradation efficiency under UV light-emitting diodes (LEDs) and the optical properties of TiO2 Degussa P25 were investigated using ketoprofen and diclofenac, two non-steroidal anti-inflammatory drugs commonly detected in German rivers. Experimental results demonstrated that thin films containing these additives exhibited similar photocatalytic degradation efficiencies as pure TiO2, achieving a 30% degradation of ketoprofen over 150 min. In contrast, the Y2O3/TiO2 thin film showed significantly improved performance, achieving a 46% degradation of ketoprofen in 180 min. Notably, the Y2O3/TiO2 system was three times more effective in degrading diclofenac compared to pure TiO2. Additionally, the Y2O3/TiO2 photocatalyst retained its activity over three successive cycles with only a slight decrease in efficiency. The photocatalytic degradation of both organic pollutants followed first-order kinetics with all photocatalysts. The investigation included SEM imaging to assess the surface homogeneity of the thin films and UV-vis solid-state spectroscopy to evaluate the impact of the additives on the energy band gap of TiO2. [ABSTRACT FROM AUTHOR]

Lead-free Mn2+-based metal halide materials are now being considered as clean candidates for backlight displays and lights due to the d–d transition, diverse components, and environmental friendliness. Therefore, efficient and stable Mn2+-based metal halide phosphors are in great demand for practical applications. In this work, adopting the mixed-ligand strategy, a series of [(CH3)4N]2−x[(C2H5)4N]xMnCl4 phosphors were synthesized by mechanochemical process. With the increase molar ratio of (CH3)4N/(C2H5)4N, the phase of phosphors is transformed from orthorhombic to tetragonal. Compared to [(CH3)4N]2MnCl4 and [(C2H5)4N]2MnCl4 phosphors, the mixed-ligand strategy significantly boosts the green emission intensity of Mn2+-based metal halide phosphors. The obtained [(CH3)4N][(C2H5)4N]MnCl4 phosphors exhibit a high photoluminescence quantum yield (PLQY) of 83.78% under 450 nm excitation, which is attributed to the modulation of the adjacent [MnCl4]2- distance by using the different chain length of organic cations, effectively suppressing non-radiative recombination. Additionally, the [(CH3)4N][(C2H5)4N]MnCl4 phosphors exhibit a green emission at 516 nm, narrow full width at half-maximum (FWHM) of 45.53 nm, and good thermal stability. The constructed white light-emitting diode (WLED) device exhibits a wide color gamut of 108.3% National Television System Committee, demonstrating the suitability of the [(CH3)4N][(C2H5)4N]MnCl4 phosphors as a green emitter for WLED displays and lightings. This work provides a new way to modulate the PL performance of manganese-based metal halides for application in the optoelectronic field. [ABSTRACT FROM AUTHOR]

Despite the many potential applications of an accurate indoor positioning system (IPS), no universal, readily available system exists. Much of the IPS research to date has been based on the use of radio transmitters as positioning beacons. Visible light positioning (VLP) instead uses LED lights as beacons. Either cameras or photodiodes (PDs) can be used as VLP receivers, and position estimates are usually based on either the angle of arrival (AOA) or the strength of the received signal. Research on the use of AOA with photodiode receivers has so far been limited by the lack of a suitable compact receiver. The quadrature angular diversity aperture receiver (QADA) can fill this gap. In this paper, we describe a new QADA design that uses only three readily available parts: a quadrant photodiode, a 3D-printed aperture, and a programmable system on a chip (PSoC). Extensive experimental results demonstrate that this design provides accurate AOA estimates within a room-sized test chamber. The flexibility and programmability of the PSoC mean that other sensors can be supported by the same PSoC. This has the potential to allow the AOA estimates from the QADA to be combined with information from other sensors to form future powerful sensor-fusion systems requiring only one beacon. [ABSTRACT FROM AUTHOR]

Uranium (U) is a radiologically and chemically toxic element that occurs naturally in water, soil, and rock at generally low levels. However, anthropogenic uranium can also leach into groundwater sources due to mining, ore refining, and improper nuclear waste management. Over the last few decades, various methods for measuring uranium have emerged; however, most of these techniques require skilled scientists to run samples on expensive instrumentation for detection or require the pretreatment of samples in complex procedures. In this work, a Schiff base ligand (P1) is used to develop a simple spectrophotometric method for measuring the concentration of uranium (VI) with an accurate and affordable light-emitting diode (LED) spectrophotometer. A test for a higher-order polynomial relationship was used to objectively determine the calibration data's linearity. This test was done with a Python program on a Raspberry Pi computer that captured the spectrophotometer's calibration and sample measurement data. [ABSTRACT FROM AUTHOR]

The development of medical, military, and other fields has greatly increased the demand for broadband near-infrared light sources. This article reports that Sr 3 Sc 2 Ge 3 O 12 : Cr3+ (SSGO: Cr3+), a broadband near-infrared phosphor with 850 nm as the luminescence center, has an emission spectrum covering 700–1200 nm and a full width at half maximum (FWHM) of 125 nm under 490 nm excitation. To further increase the FWHM value, Yb3+ is introduced into the phosphor of SSGO: Cr3+ to enable energy transfer from Cr3+ to Yb3+. After doping 1 % of Yb3+ onto the Sr2+ site, the near-infrared emission generated by the 4A 2 →4T 1 (4P) transition of Cr3+ and the near-infrared emission generated by the 2F 5/2 → 2F 7/2 transition of Yb3+ work so that the FWHM increases to 220 nm. In addition, the thermal stability of the phosphor after co-doping with Yb3+ is also greatly enhanced from 61.6 % to 75.1 % by comparing it to the Cr3+ single-doped sample. In addition, SSGO:0.08Cr3+, 0.01 Yb3+ was combined with a commercial 490 nm chip to prepare a broadband near-infrared light-emitting diode (pc-LED). [ABSTRACT FROM AUTHOR]

Different wavelengths emitted from light-emitting diodes (LEDs) are known as an influential factor in proliferation and differentiation of various cell types. Since human umbilical cord matrix-derived mesenchymal cells (hUCMs) are ideal tools for human regenerative medicine clinical trials and stem cell researches, in the present study we investigated the neurogenesis effects of single and intermittent green and red LED irradiation on hUCM cells. Exposure of hUCMs to single and intermittent green (530 nm, 1.59 J/cm2) and red (630 nm, 0.318 J/cm2) lights significantly increased the expression of specific genes including nestin, β-tubulin III and Olig2. Additionally, immunocytochemical analysis confirmed the expression of specific neural-related proteins including nestin, β-tubulin III, Olig2 and GFAP. Also, alternating exposure of hUCM cells to green and red lights increased the expression of some neural markers more than either light alone. Further research are required to develop the application of LED irradiation as a useful tool for therapeutic purposes including neural repair and regeneration. [ABSTRACT FROM AUTHOR]

Fully π-conjugated polymers with rigid aromatic units are promising for flexible optoelectronic devices, but their inherent brittleness poses a challenge for achieving high-performance, intrinsically stretchable fully π-conjugated polymer. Here, we are establishing an external-plasticizing strategy using semiconductor fluid plasticizers (Z1 and Z2) to enhance the optoelectronic, morphological, and stretchable properties of fully π-conjugated polymer films for flexible light-emitting diodes. The synergistic effect of hierarchical structure and optoelectronic properties of Z1 in poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) films enable excellent stretchable deformability (~25%) and good conductivity. PLEDs based on F8BT/Z1 films show stable electroluminescence and efficiency under 15% stretch and 100 cycles at 10% strain, revealing outstanding stress tolerance. This strategy is also improving the stretchable properties of polymers like poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) and poly(2-methoxy-5(2′-ethyl)hexoxy-phenylenevinylene) (Super Yellow), demonstrating its general applicability. Therefore, this strategy can provide effective guidance for designing high-performance stretchable fully π-conjugated polymers films for flexible electronic devices. The realization of intrinsically stretchable fully π-conjugated polymer film is challenging due to their inherent brittle nature. Here, authors apply semiconductor fluid molecular plasticizers to improve stretchable deformability, achieving high performance flexible polymer light-emitting diodes. [ABSTRACT FROM AUTHOR]

Near infrared (NIR) light has been shown to provide beneficial treatment of traumatic brain injury (TBI) and other neurological problems. This concept has spawned a plethora of commercial entities and practitioners utilizing panels of light emitting diodes (LEDs) and promising to treat patients with TBI and other disorders, who are desperate for some treatment for their untreatable conditions. Unfortunately, an LED intended to deliver photonic energy to the human brain does not necessarily do what an LED pointed at a mouse brain does. There is a problem of scale. Extensive prior research has shown that infrared light from a 0.5-watt LED will not penetrate the scalp and skull of a human. Both the properties of NIR light and the manner in which it interacts with tissue are examined. Based on these principles, the shortcomings of current approaches to treating neurological disorders with NIR light are explored. Claims of clinical benefit from low-level LEDbased devices are explored and the proof of concept challenged. To date, that proof is thin with marginal benefits which are largely transient. Extensive research has shown fluence at the level of the target tissue which falls within the range of 0.9J/cm2 to 15J/cm2 is most effective in activating the biological processes at the cellular level which underlie direct photobiomodulation. If low-level infrared light from LED devices is not penetrating the scalp and skull, then these devices certainly are not delivering that level of fluence to the neurons of the subjacent brain. Alternative mechanisms, such as remote photobiomodulation, which may underlie the small and transient benefits for TBI symptoms reported for low-power LED-based NIR studies are presented. Actionable recommendations for the field are offered. [ABSTRACT FROM AUTHOR]

Although luminescent aluminum compounds have been utilized for emitting and electron transporting layers in organic light-emitting diodes, most of them often exhibit not phosphorescence but fluorescence with lower photoluminescent quantum yields in the aggregated state than those in the amorphous state due to concentration quenching. Here we show the synthesis and optical properties of β-diketiminate aluminum complexes, such as crystallization-induced emission (CIE) and room-temperature phosphorescence (RTP), and the substituent effects of the central element. The dihaloaluminum complexes were found to exhibit the CIE property, especially RTP from the diiodo complex, while the dialkyl ones showed almost no emission in both solution and solid states. Theoretical calculations suggested that undesired structural relaxation in the singlet excited state of dialkyl complexes should be suppressed by introducing electronegative halogens instead of alkyl groups. Our findings could provide a molecular design not only for obtaining luminescent complexes but also for achieving triplet-harvesting materials. Luminescent aluminum compounds have been utilized for emitting and electron transporting layers in organic light-emitting diodes, but most exhibit fluorescence as opposed to phosphorescence. Here, the photophysical properties of β-diketiminate aluminum complexes are shown to depend on the nature of the metal substituents, with a diiodoaluminum complex displaying room temperature phosphorescence. [ABSTRACT FROM AUTHOR]

A weak van der Waals (vdW) force in layered materials enables their isolation into thin flakes through mechanical exfoliation while sustaining their intrinsic electronic and optical properties. Here, we introduce a universal roll-printing method capable of producing vdW multilayer films on wafer-to-meter scale. This process uses sequential exfoliation and transfer of layered materials from the powder sources to target substrates through a repeated rolling of a cylindrical metal drum. We achieve uniformly coated films with a library of vdW powders on various mechanically rigid and flexible substrates. The printed films are configured into different devices including light-emitting diodes and photodetectors. The presented technique offers substantial benefits in terms of cost efficiency and a low thermal budget while offering high material quality. [ABSTRACT FROM AUTHOR]

The poor operational stability of perovskite light-emitting diodes (PeLEDs) remains a major obstacle to their commercial application. Achieving high brightness and quantum efficiency at low driving voltages, thus effectively reducing heat accumulation, is key to enhancing the operational lifetime of PeLEDs. Here, we present a breakthrough, attaining a record-low driving voltage while maintaining high brightness and efficiency. By thoroughly suppressing interface recombination and ensuring excellent charge transport, our PeLEDs, with an emission peak at 515 nanometers, achieve a maximum brightness of 90,295 candelas per square meter and a peak external quantum efficiency of 27.8% with an ultralow turn-on voltage of 1.7 volts (~70% bandgap voltage). Notably, Joule heat is nearly negligible at these low driving voltages, substantially extending the operational lifetime to 7691.1 hours. Our optimized strategies effectively tackle stability issue through thermal management, paving the way for highly stable PeLEDs. [ABSTRACT FROM AUTHOR]

A novel near-infrared emitting Ga 2 O 3 : Ni2+ phosphor was prepared, and its emission characteristics were improved through melting aid and charge balance. Under 410 nm excitation, the Ga 2 O 3 : Ni2+ phosphor exhibits broadband near-infrared emission in the second region, with a peak at 1455 nm and a half maximum width of up to 300 nm. At the same time, the crystallinity of the sample was improved and the charge imbalance during substitution between Ga3+ and Ni2+ was eliminated through melting assistance and charge compensation. The results show that the emission intensity of Ga 1.97 O 3 : 0.015Ni2+, 0.015Ge4+ phosphor (with added flux H 3 BO 3) is 10 times higher than that of Ga 1.985 O 3 : 0.015Ni2+ sample. Its quantum yield is as high as 31.2 %, significantly higher than the reported Ni2+ ion doped phosphors. According to the distinct absorptions of C–H, O–H as well as N–H bonds in the shortwave near-infrared range, samples of ethanol, n-hexanol, water and ammonia demonstrated different absorption peaks under the penetration of the constructed phosphor conversion light-emitting diode, which proved the potential application of Ga 2 O 3 : Ni2+, Ge4+-H 3 BO 3 phosphor in composition analysis and detection. [ABSTRACT FROM AUTHOR]

Broadband near-infrared (NIR) light sources cover unique optical wavelengths and are valuable in the fields of bioimaging and photodynamic therapy, night vision lighting and security monitoring. NIR phosphor converted light-emitting diode (NIR pc-LED) devices have attractive features such as tunable emission peak, low cost of production, compact in sizes and high luminous efficiency. However, heat accumulation during operation due to poor thermal conductivity of the organic resin used in packaging often causes serious reduction in luminous efficiency and accelerated degradation of the device. In present work, we developed a Cr3+-doped transparent CaF 2 -based oxy-fluoride glass-ceramic (GC) that showed a broadband emission of 700∼1400 nm under 470 nm excitation. The emission peaked at ∼880 nm, the full-width at half maximum was about ∼297 nm, and the photoluminescence quantum yield reached ∼31.19 %. The emission was derived from the electronic transition of Cr3+ ions from the 4T 2 (F) to 4A 2 (F). Through structural analysis and numerical simulation, we showed that during the heat treatment process, Cr3+ ions were enriched into the CaF 2 crystal phase and replaced the Ca2+ in the GC host with occupied the center position of the polyhedrons, which provided a weak crystal field and led to NIR emission. We built NIR pc-LED devices using optimized GC and commercial blue LED chips, and we demonstrated the application of this NIR pc-LED in night-vision lighting. Our approaches to prepare simple and stable inorganic NIR luminous materials sealed in bulk in a transparent CaF 2 -based oxy-fluoride GC and to construct pc-LED devices could provide new concept to the field and have practical implications to applications in related fields. [ABSTRACT FROM AUTHOR]

Developing near-infrared (NIR) phosphors with high thermal stability and broadband emission is pivotal for advancing NIR light sources. In this study, we synthesized a novel borate phosphor, GdGa 3 (BO 3) 4 :Cr3+, via a high-temperature solid-state reaction. This phosphor demonstrates exceptional thermal stability, maintaining 94 % of its initial intensity even at 150 °C. Upon blue light excitation, it emits a broad spectrum from 650 to 1100 nm, peaking at 770 nm with a full width at half maximum (FWHM) of ∼130 nm. We conducted a comprehensive investigation to understand the mechanisms underlying its thermal stability. Additionally, by combining the GdGa 3 (BO 3) 4 :15%Cr3+ phosphor with a commercial blue light chip, we fabricated an NIR LED device achieving a NIR output power of 6.45 mW and a photoelectric conversion efficiency of 1.57 % at 120 mA. This study offers valuable insights into the design of advanced NIR phosphors with superior thermal stability for NIR light source applications. [Display omitted] • A new broadband NIR phosphor GdGa 3 (BO 3) 4 :Cr3+ is synthesized. • The phosphor exhibits a broadband NIR emission at 770 nm (FWHM = 130 nm). • The phosphor retains 94 % of its initial luminescence intensity even at 150 °C. • The mechanism of its exceptional thermal stability is thoroughly investigated. [ABSTRACT FROM AUTHOR]

Rapid and accurate bacterial identification is essential for timely treatment of infections like sepsis. While traditional methods are reliable, they lack speed, and advanced molecular techniques often suffer from cost and complexity. The bacterial detection technology based on optical scattering system offers a rapid, label-free alternative but traditionally relies on complex lasers and analysis. Our enhanced approach utilizes RGB light emitting diodes (LEDs) as the light source. Three diffraction images of bacterial colonies from different LED colors are separately captured by a USB camera and combined using an image registration algorithm to enhance image sharpness. Our approach utilizes an object detection model, i.e., YOLOv8, for analysis achieving high-accuracy differentiation between bacterial strains. We demonstrate the effectiveness of this approach, achieving an average accuracy of 97% (mAP50 of 0.97), including accurate discrimination of closely related strains and the significant pathogen Staphylococcus aureus MRSA 1320. Our enhancement offers advantages in affordability, usability, and seamless integration into existing workflows, providing an alternative for rapid bacterial identification. [ABSTRACT FROM AUTHOR]

Large-area imaging techniques in the short-wave infrared spectral region remain a pressing need. Organic light-emitting diodes and infrared photodetectors can be combined to form a near-infrared (NIR) to visible upconversion device, which has great potential to replace traditional infrared imaging systems. The integration of a white organic light-emitting diode (WOLED) with infrared photodetectors has become essential to realize full-color displays for its simple preparation process and high compatibility. This work has designed and optimized a WOLED to achieve stable emission with high brightness (19 470 cd m−2) and high external quantum efficiency (EQE = 18.08%) at a wide voltage range, thereby reducing chromaticity drift caused by voltage fluctuations. Moreover, photon-generated holes in the NIR-sensitive photodetector are able to inject into the WOLED for visible light emission. Consequently, we have obtained a high-performance upconversion device with a luminance on-off ratio exceeding 5 × 103 at 850 nm NIR and a high color stability over a wide range of operating voltage. Our efforts have accomplished a high-performance upconversion device from NIR to white visible light, laying the groundwork for a preliminary exploration of full-color displays. [ABSTRACT FROM AUTHOR]

Zinc-ion batteries (ZIBs) have become a highly desirable energy storage technology due to their significant advantages, such as low cost and high safety; however, the limitation of cathode materials has become a major factor restricting the development of ZIBs. Here, molybdenum diselenide (MoSe2) nanoflakes were investigated for the first time as a novel cathode for ZIBs. The unique two-dimensional (2D) layered structure of MoSe2 provides convenient channels and multiple active sites for zinc (Zn) ion diffusion. MoSe2 showed a specific capacity of 30.1 mA h/g at 0.1 A/g as well as almost no capacity decay at 1.0 A/g after 1500 cycles. Further, the Zn–MoSe2 coin cell successfully excited a light-emitting diode, showing good application prospects. Moreover, there was almost no aging of the battery after cycling, thus indicating satisfactory application potential. This work broadens the application of 2D materials in ZIBs. [ABSTRACT FROM AUTHOR]

The Sideritis genus includes over 150 species primarily found in the Mediterranean basin, including the S. clandestina subsp. pelopponesiaca from the Peloponnese and S. scardica from North and Central Greece. In vitro seed germination has proven effective for conserving and amplifying the genetic diversity of endangered species such as Sideritis. This study aimed to optimize in vitro germination and seedling growth of S. scardica and S. clandestina subsp. pelopponesiaca under different lighting conditions at 22 °C, including white fluorescent lamps (WFL-BG-40) and LEDs (LED-BGYOR-40, LED-BR-40, LED-BR-80, LED-BR-120) all under a 16-h light/8-h dark photoperiod (WFL: white fluorescent light, B:blue, G:green, Y:yellow, O:orange, R:red, 40–80–120 μmol m−2 s−1), along with a 24-h dark treatment. The results indicated that LED-BR-80 combined with 250 mg L−1 GA3 in the MS medium promoted best germination (40%, day 55) and shoot proliferation in S. clandestina subsp. pelopponesiaca. Conversely, 5-year-old cold stratified S. scardica seeds showed higher germination rates (80%) and robust seedling growth under LED-BGYOR-40 with 250 mg L−1 GA3, particularly thriving in LED-BR-120 for increased shoot height and root number. This is the first report of the efficacy of LED technology in optimizing in vitro conditions for Sideritis species, crucial for their conservation and sustainable commercial cultivation. [ABSTRACT FROM AUTHOR]

Light and temperature are the driving forces in plant development and growth. Specific photoreceptors provide the ability to sense and interpret light and temperature to regulate growth. Under the limited light conditions in most sports stadiums, natural grasses suffer from light deficiency. Artificial light provided by light-emitting diodes (LEDs) is used to increase their growth and adjust their development. Flavonoids like flavonols and anthocyanins are influenced by light conditions and temperature. Increased blue light can elevate the content of these secondary metabolites. Remote measurements of internal parameters using non-destructive methods provided information on their content under different temperature conditions for quality monitoring. This experiment tested flavonoid contents in Kentucky bluegrass (Poa pratensis) for different blue-to-red light ratios (0.6 and 0.4) and three temperature courses (constant temperature of 4 °C, constant temperature of 12 °C, and temperature switching among 12–8–4–8–12 °C). The results show elevated levels of flavonoids under blue-dominant artificial light as well as increased content under low-temperature (4 °C) conditions. The lack of flavonoids at elevated temperatures (12 °C), especially under red-dominant light, suggests an increased requirement for artificial blue light at increased temperatures. Non-destructive flavonoid determination was suitable for this experiment and can therefore be used for practical sports turf quality monitoring. [ABSTRACT FROM AUTHOR]

A new class of BaLiZn3(BO3)3:RE (RE = Sm3+, Tb3+, Dy3+, and Pb2+) phosphors were synthesized with a solid- state reaction method. The minor concentrations of various rare earth (Tb3+, Dy3+, and Sm3+) ions and transition metal (Pb2+) ions activated in the BaLiZn3(BO3) host matrix were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy. The XRD results of BaLiZn3(BO3)3:RE (RE = Sm3+, Tb3+, Dy3+, and Pb2+) phosphors confirmed that all the samples have a monoclinic phase. SEM studies revealed that the morphology of BaLiZn3(BO3)3:RE (RE = Sm3+, Tb3+, Dy3+, and Pb2+) phosphors was irregular. The photoluminescence emission and excitation spectra show that these phosphors can be effectively excited by near-ultraviolet light-emitting diodes (n-UV), and they all exhibit an efficient orange-red (Sm3+, 4G5/2 → 6H7/2), green (Tb3+, 5D4 → 7F5), yellow (Dy3+, 4F9/2 → 6H13/2), and blue (Pb2+, 3P1 → 1S0) emission. All of the above results confirmed that the obtained phosphors could be a potential candidate for n-UV-excited WLEDs. [ABSTRACT FROM AUTHOR]

In recent years, near-infrared (NIR) phosphors have attracted great research interest due to their unique physical properties and broad application prospects. However, obtaining NIR phosphors with both high quantum efficiency and excellent thermal stability remains a great challenge. In this study, novel NIR Ca3Mg2ZrGe3O12:Cr3+ phosphors were successfully prepared using a high-temperature solid-phase method, and the structure and luminescent properties of the material were systematically investigated. Ca3Mg2ZrGe3O12:0.01Cr3+ emits NIR light in the range of 600 to 900 nm with a peak at 758 nm and a half-height width of 89 nm under the excitation of 457 nm blue light. NIR luminescence shows considerable quantum efficiency, and the internal quantum efficiency of the optimized sample is up to 68.7%. Remarkably, the Ca3Mg2ZrGe3O12:0.01Cr3+ phosphor exhibits a near-zero thermal quenching behavior, and the luminescence intensity of the sample at 250 °C maintains 92% of its intensity at room temperature. The mechanism of high thermal stability has been elucidated by calculating the Huang Kun factor and activation energy. Finally, NIR pc-LED devices prepared from Ca3Mg2ZrGe3O12:0.01Cr3+ phosphor with commercial blue LED chips have good performance, proving that this Ca3Mg2ZrGe3O12:0.01Cr3+ NIR phosphor has potential applications in night vision and biomedical imaging. [ABSTRACT FROM AUTHOR]

Quaternary (AlxGa1−x)yIn1−yP alloys grown on GaAs substrates have recently gained considerable interest in photonics for improving visible light-emitting diodes, laser diodes, and photodetectors. With two degrees of freedom (x, y) and keeping growth on a lattice-matched GaAs substrate, the (AlxGa1−x)0.5In0.5P alloys are used for tuning structural, phonon, and optical characteristics in different energy regions from far-infrared (FIR) → near-infrared (NIR) → ultraviolet (UV). Despite the successful growth of (AlxGa1−x)0.5In0.5P/n+-GaAs epilayers, limited optical, phonon, and structural characteristics exist. Here, we report our results of carefully examined optical and vibrational properties on highly disordered alloys using temperature-dependent photoluminescence (TD-PL), Raman scattering spectroscopy (RSS), and Fourier-transform infrared reflectivity (FTIR). Macroscopic models were meticulously employed to analyze the TD-PL, RSS, and FTIR data of the (Al0.24Ga0.76)0.5In0.5P/n+-GaAs epilayers to comprehend the energy-dependent characteristics. The Raman scattering and FTIR results of phonons helped analyze the reflectivity spectra in the FIR region. Optical constants were carefully integrated in the transfer matrix method for evaluating the reflectivity R (E) and transmission T (E) spectra in the NIR → UV regions, validating the TD-PL measurements of bandgap energies (E g P L) . [ABSTRACT FROM AUTHOR]

Polyimide (PI) refers to a type of high-performance polymer containing imide rings in the main chain, which has been widely used in fields of aerospace, microelectronic and photonic devices, gas separation technology, and so on. However, traditional aromatic PIs are, in general, the inefficient fluorescence or even no fluorescence, due to the strong inter- and intramolecular charge transfer (CT) interactions causing unavoidable fluorescence quenching, which greatly restricts their applications as light-emitting functional layers in the fabrication of organic light-emitting diode (OLED) devices. As such, the development of fluorescent PIs with high fluorescence quantum efficiency for their application fields in the OLED is an important research direction in the near future. In this review, we provide a comprehensive overview of fluorescent PIs as well as the methods to improve the fluorescence quantum efficiency of PIs. It is anticipated that this review will serve as a valuable reference and offer guidance for the design and development of fluorescent PIs with high fluorescence quantum efficiency, ultimately fostering further progress in OLED research. [ABSTRACT FROM AUTHOR]

Colonoscopy has a limited field of view because it relies solely on a small camera attached to the end of the scope and a screen displayed on a monitor. Consequently, the quality and safety of diagnosis and treatment depend on the experience and skills of the gastroenterologist. When a novice attempts to insert the colonoscope during the procedure, excessive pressure can sometimes be applied to the colon wall. This pressure can cause a medical accident known as colonic perforation, which the physician should prevent. We propose an assisting device that senses the pressure applied to the colon wall, analyzes the risk of perforation, and warns the physician in real time. Flexible pressure sensors are attached to the surface of the colonoscope shaft. These sensors measure pressure signals during a colonoscopy procedure. A simple signal processor is used to collect and process the pressure signals. In the experiment, a colonoscope equipped with the proposed device was inserted into a simulated colon made from a colon extracted from a pig. The processed data were visually communicated to the gastroenterologist via displays and light-emitting diodes (LEDs). The device helps the physician continuously monitor and prevent excessive pressure on the colon wall. In this experiment, the device appropriately generated and delivered warnings to help the physicians prevent colonic perforation. In the future, the device is to be improved, and more experiments will be performed in live swine models or humans to confirm its efficacy and safety. [ABSTRACT FROM AUTHOR]

Far‐red‐emitting (700−740 nm) phosphors are essential for the fabrication of plant lighting phosphor‐converted light‐emitting diodes (pc‐LEDs). However, the development of highly efficient, thermally stable, and spectrally matched far‐red phosphors still remains a challenge. Herein, far‐red GdAlO3:Cr3+ (GAO:Cr3+) phosphors were synthesized via solid‐state reaction and investigated for plant lighting pc‐LED applications. A low‐temperature flux‐assisted synthesis strategy was adopted to improve the crystalline quality, suppress the defect formation, and maintain the valence state of Cr3+ in the phosphors, finally leading to significant luminescent enhancement (∼10 times). The GAO:Cr3+ phosphors show the 2E sharp‐line emissions around 730 nm, which is highly matched with the far‐red absorption band of plants. The optimized GAO:0.01Cr3+ phosphor exhibits a high internal quantum efficiency of 98.3% and zero thermal quenching even up to 250°C. The fabricated pc‐LED can generate an overall output power of 78.1 mW at 100 mA drive current, with a high energy conversion efficiency of 25.3%. The findings demonstrate the great potential of GAO:Cr3+ as far‐red‐emitting phosphor materials for plant growth pc‐LED applications. [ABSTRACT FROM AUTHOR]

This article investigates the performance of a contact-mode Triboelectric Nanogenerator (TENG) utilizing polydimethylsiloxane (PDMS) with nano gratings as a dielectric in a metal-dielectric configuration. The evaluation encompasses the impact of gratings, tapping frequency, various load conditions, and contact area on the TENG performance. The fabrication involves spin-coating PDMS onto a master mold to create the device. Experimental measurements reveal a significant enhancement of 97% in open-circuit voltage by introducing gratings on PDMS. Furthermore, as the tapping frequency increases from 1 Hz to 3 Hz, there is a corresponding rise of 108% in output voltage. The influence of load resistance on TENG output performance demonstrates its ability to drive different loads efficiently. Moreover, enlarging the contact area of the device substantially increases the open-circuit voltage. A device with a 400 mm2 contact area can generate a voltage of 80 V at a low frequency of 3 Hz, indicating the importance of considering device size and contact area for specific applications. A practical circuit integrating a TENG with a full-wave bridge rectifier demonstrates energy harvesting capabilities by successfully illuminating a light-emitting diode (LED) and charging various capacitors. The fabricated devices exhibit better performance along with a cost-effective and easy fabrication process. [ABSTRACT FROM AUTHOR]

The precursor glasses consisting of 50SiO 2 –20B 2 O 3 –20Na 2 O–6ZnO–3MoO 3 -1Ln 2 O 3 -0.5Eu 2 O 3 (Ln = Gd/La/Y) were effectively synthesized using the melt-quenching technique. NaGd(MoO 4) 2 : Eu3+ transparent glass-ceramics with La3+/Y3+ substituting for Gd3+ was successfully prepared during heat treatment. The XRD analysis revealed the formation of NaGd(MoO 4) 2 crystals (nanoscale) within the glass matrix following the application of heat treatment. The study revealed that the Eu3+ ions emitted the strongest light at a wavelength of 615 nm (red luminescence) when they were excited by a wavelength of 394 nm. The enhancement of the red luminescence in NaGd(MoO 4) 2 : Eu3+ glass-ceramics is achieved through a combination of lanthanide contraction effects and the lattice environment surrounding the Eu3+ ions when La3+/Y3+ are substituted for Gd3+. Through the evaluation of the photoluminescence color stability and thermal stability of glass-ceramic, it is confirmed that NaLn(MoO 4) 2 : Eu3+ transparent glass-ceramic has excellent red luminescence performance, which is a highly promising candidate for utilization in light-emitting diodes. [ABSTRACT FROM AUTHOR]

High-quality white light can be obtained from a mixture of blue, green, and red phosphors excited by ultraviolet chips. However, this approach suffers from the presence of a cyan gap in the emission spectra, which hinders further improvement in the color rendering index (CRI). The obvious solution to this problem should be the development of efficient ultraviolet-excited cyan phosphors to fill this gap. Therefore, a series of Y 2 LaCaGa 3 ZrO 12 : x Bi3+ (x = 0–0.1) cyan phosphors were synthesized via high-temperature solid-state reaction method, and their properties were systematically characterized. The Bi3+ ion in Y 2 LaCaGa 3 ZrO 12 exhibits dual-mode luminescence with emission bands peaking at 356 nm and 483 nm, originating from the 3P 1 →1S 0 transitions of Bi3+ at different sites. The ultraviolet emission is attributed to Bi3+ occupying 8 coordination sites, while the cyan emission arises from Bi3+ in 6 coordination sites. It is noteworthy that the emission intensity and thermal stability of the phosphors can be further improved by partially substituting Ga3+ with Al3+. By incorporating Y 2 LaCaGa 3 ZrO 12 : 0.02Bi3+ or Y 2 LaCaGa 2.7 Al 0.3 ZrO 12 : 0.02Bi3+ with commercial phosphors and depositing them onto a 365 nm ultraviolet chip, the prototype white light emitting diodes (w-LEDs) exhibits white light with high CRI of 89.6 and 90.4, respectively. These results validate the potential of Bi3+ activated Y 2 LaCaGa 3- y Al y ZrO 12 (y = 0–1) cyan phosphor as a promising candidate material for application in UV-excited w-LEDs. [ABSTRACT FROM AUTHOR]