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Lead halide perovskite nanocrystals (PNCs) have emerged as new-generation light-emitting materials with important potentials in optoelectronic applications. However, the toxicity of lead metal and ...

Currently, due to the advantages of fast response, remote operations and good stability, non-contact optical temperature measurement technology based on fluorescence intensity ratio (FIR) has attracted intensive attention. Here, we successfully developed a novel Pr3+, Tb3+ co-doped YNbO4 phosphor which can be used as a non-contact optical thermometer. Under excitation at 295 nm, Pr3+, Tb3+ co-doped YNbO4 emits red light from Pr3+ (1D2 → 3H4) and green light from Tb3+ (5D4 → 7F5), simultaneously. Based on strong dependence of the emission intensity on temperature, the FIR of red and green emissions is designed as detection signal to accurately monitor temperature. The maximum absolute and relative sensitivities reached as high as 0.0125 K−1 at 508 K and 1.01% K−1 at 478 K, respectively. The luminous color of this phosphor is sensitive to the temperature, which provides the possibility for visualization of temperature measurement. There was little change in the luminescence intensity of Pr3+, Tb3+ co-doped phosphors after they went through five heating-cooling cycles. It is proved that the multi-phonon relaxation from 3P0 to 1D2 and intermediate charge transfer are responsible to the temperature-dependent luminescence of the phosphors. Optical thermometer based on the current phosphors show the advantages of high sensitivity, high precision and good repeatability. This indicates Pr3+, Tb3+ co-doped phosphors have potential application value in optical temperature sensing field.

Morphological and structural characteristics of semiconductors have a significant impact on their gas sensing characteristics. Reasonable design and synthesis of heterojunctions with special structures can effectively improve sensor performance. Herein, a cobalt oxide (Co3O4) nanofibers/cadmium sulfide (CdS) nanospheres hybrid was synthesized by an electrospinning method combined with a hydrothermal method to detect acetone gas. By adjusting loading amount of CdS, the sensing performance of CdS/Co3O4 sensor for acetone at room temperature (25 °C) was greatly ameliorated. In particular, the response of CdS/Co3O4 to 50 ppm acetone gas increased by 25% under 520 nm green light, meanwhile, the response/recovery time was shortened to 5 s/4 s. This is attributed to the heterojunction formed between CdS and Co3O4 as well as the influence of light excitation on the carrier concentration of the surfaces. Meanwhile, the unique high-porosity fiber structure and the catalytic action of cobalt ions also play an essential role in improving the performance. Furthermore, practical diabetic breath was experimentally simulated and proved the potential of the sensor in the future application of disease-assisted diagnosis.

Phosphors of SrAl2O4:Eu (SAO), B-doped (SBO), and B, F co-doped (SFO) were prepared by a high-temperature solid-state reaction method. The phosphors emit intense green light under UV excitation. SBO displayed significantly enhanced long afterglow. The decay time of SBO was 20 times bigger than that of SAO, while that of SFO was only 16% of that of SBO. The results suggest that B doping favors the formation of oxygen vacancies due to the unique bonding property of B. At the same time, B, F co-doping has the opposite effect, ascribed to the presence of F. The related partial density of state and the orbital structures were calculated using the first-principles density functional theory (DFT). The orbital structure of SBO showed that high partial density states are localized around the O vacancies, which can trap excited electrons, leading to improved long-afterglow luminescence.

The effect of thymine as a buffer layer has been examined on the performance of organic photodetectors. As the decreasing dark current with incorporation of buffer layer, a significant increase in ...

Cadmium sulfide (CdS) is an important semiconductor material that has been utilized constructively for various modern applications. There were lot of works regarding the preparation of CdS nanoparticles. The present work has utilized a chemical precipitation method with and without using a capping agent. Even though the solvent system used for the preparation is a new one and provides a non-toxic reaction medium, this work mainly focused on the advantages of surface capping on nanoparticles. CdS nanoparticles prepared by surface capping with oleic acid (OA) exhibit many unique properties compared to the uncapped nanoparticles. The coral shaped surface morphology and the bright green fluorescence observed in OA capped CdS nanoparticles were not reported elsewhere. Strong absorption of radiation in the visible as well as in the ultraviolet region with a large band gap was also observed in capped CdS nanoparticles. Blue shift in emission with an intense peak was another unique character observed in the surface capped CdS nanoparticles. Morphological, structural, optical and thermal properties of the capped and uncapped CdS nanoparticles were systematically investigated.

The color and nutritional quality of vegetables directly affect the choices of consumers and thus affect the commercial value of the vegetable products. Green light can penetrate the outer leaves and reach the inner leaves to promote photochemical reaction of the overlapping leaves of head vegetables. However, whether this promotion can increase the nutritional components and change the color of the inner leaves of head cabbages, which is one of the major head vegetables largely produced worldwide, remains unclear. Therefore, we investigated the changes in the colors and the concentrations of chlorophyll (Chl) and carotenoid of the inner leaves of two types of cabbages by externally irradiating the cabbage with green light. The results showed that a short-term (48 h) irradiation with low light intensity (50 μmol m−2 s−1) of green light enhanced the Chl concentration and colors of the inner leaves of cabbages, and the positive changes of these indicators increased as the leaf layers approached the head center of the cabbage. Simultaneously, we also establish a method to effectively estimate the Chl concentration using luminosity (L*) and greenness (− a*) when the Chl concentration is so low that it is difficult or not possible to be measured by SPAD meter. Our findings demonstrated that green light, as a new tool, can be used to control the colors and nutritional components of the inner leaves of cabbages. The discoveries will help produce head vegetables with the preferred phenotype desired by consumers using a plant factory with artificial lighting.

Quantum dots (QDs) are ideal color-conversion materials for display fields. Preparation of micro-nanostructures is a mainstream method for obtaining a high photoluminescence (PL) intensity. Electrical induction, a method of preparing micro-nanostructures, was introduced to obtain QD films with high PL performance by preparing a sandwich column array structure (SCAS). By changing the spacer thickness, a series of SCAS-QD films were fabricated, after optimizing the voltage. The SCAS-QD layers with a 25- $\mu \text{m}$ spacer obtained the maximum PL enhancement of green light intensity: up to 42.8%. The enhancement was caused by the microcavity trapping and light extraction effects. The former could increase the utilization factor of blue light and the latter could increase the emission probability of green light. This is a simple, high-efficient, and low-cost method for preparing QD films with high PL performance without increasing the QD concentration.

Photo-responsive cholesteric liquid crystals (CLCs) have attracted much attention in recent years due to their wide applications in filters, tunable optical lasers, dynamic display devices, etc. However, UV light is usually used as the external stimulus source, which is not environment-friendly enough. On the other hand, the mechanical properties of CLCs are not strong enough for these practical applications. Therefore, it still remains a challenge to endow the CLCs with visible light response and high mechanical properties at the same time. Herein, an axially chiral tetra-fluorinated binaphthyl azobenzene gelator ( S-4F-AG ) is synthesized. Upon 550 and 450 nm light irradiations, S-4F-AG exhibits excellent photo-switchable behaviors. Notably, the maximum content of cis-isomer and its half-life are as high as 35% and 89 h in acetonitrile, respectively. A self-supporting CLC physical gel with a storage modulus around 104 Pa can be obtained when 3wt% S-4F-AG and 12wt% binaphthyl azobenzene derivative (dopant 2 ) are co-doped into a nematic LC host P0616A. This CLC physical gel exhibits a temperature-driven blue, green, and red reflection colors reversibly. Importantly, such three primary RGB colors can also be realized by adjusting the exposure time of 550 nm green light. This work lays a solid foundation for the applications ranging from information storage to high-tech anticounterfeit.

A homojunction-structured oxide phototransistor based on a mechano-chemically treated indium-gallium-zinc oxide (IGZO) absorption layer is reported. Through this novel and facile mechano-chemical treatment, mechanical removal of the cellophane adhesive tape induces reactive radicals and organic compounds on the sputtered IGZO film surface. Surface modification, following the mechano-chemical treatment, caused porous sites in the solution-processed IGZO film, which can give rise to a homojunction-porous IGZO (HPI) layer and generate sub-gap states from oxygen-related defects. These intentionally generated sub-gap states played a key role in photoelectron generation under illumination with relatively long-wavelength visible light despite the wide band gap of IGZO (>3.0 eV). Compared with conventional IGZO phototransistors, our HPI phototransistor displayed outstanding optoelectronic characteristics and sensitivity; we measured a threshold voltage (Vth) shift from 3.64 to -6.27 V and an on/off current ratio shift from 4.21 × 1010 to 4.92 × 102 under illumination with a 532 nm green light of 10 mW/mm2 intensity and calculated a photosensitivity of 1.16 × 108. The remarkable optoelectronic characteristics and high optical transparency suggest optical sensor applications.

A several of LiLaSiO4: xTb3+, ySm3+ (LLSO) phosphors were synthesized by high-temperature solid-phase reaction. Through SEM, XRD and fluorescence spectrometer, the phase, morphology, luminescence properties and energy transfer of the samples were systematically analyzed and discussed. Under an excitation of 378 nm wavelength, LLSO: xTb3+ phosphors emit green light, and the concentration quenching point of Tb3+ ions was x = 0.08. In LLSO: xTb3+, ySm3+ phosphors, When Sm3+ ions doping molar mass fraction increases, the fluorescence intensity of Tb3+ ion decreases while the fluorescence intensity of Sm3+ ions first strengthen and then weaken. The concentration quenching point of Sm3+ ions was y = 0.04. By changing the proportion of Sm3+ and Tb3+ ions, the luminous color can be adjusted from green to red. There is effective energy transfer between Tb3+→Sm3+. The molar mass fraction of doping Sm3+ ions is y = 0.10, the energy transfer efficiency reaches 96.67%. The energy transfer mechanism is the quadrupole-quadrupole interaction. The quantum yield is 22.34%. Therefore, LLSO: xTb3+, ySm3+ phosphors have certain potential application value in the field of ultraviolet-near ultraviolet white LEDs.

La2O2S:Tb3+ hollow nanofibers were successfully fabricated by sulfurization of the relevant La2O3:Tb3+ hollow nanofibers via double-crucible method. The morphology and properties of the products were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrometry. La2O2S:Tb3+ hollow nanofibers were pure hexagonal phase with space group P $$\bar {3}$$ m1 and were hollow-centered structure with the mean diameter of 160.03 ± 17.74 nm. Emission spectra indicate that La2O2S:Tb3+ hollow nanofibers emit green light at 544 nm attributed to 5D4 → 7F5 energy levels transition of Tb3+ ions. CIE analysis demonstrated that the light emitted by La2O2S:Tb3+ hollow nanofibers corresponds to the green region, and color-tuned luminescence can be obtained by changing concentration of Tb3+ ions. The obtained material could be applied in the field of optical telecommunication and optoelectronic devices. The possible formation mechanism of La2O2S:Tb3+ hollow nanofibers was also proposed.

Schiff base copper complex for OLEDs application was synthesized and ligand was characterized by NMR, mass spectroscopy, FTIR, and powder XRD. Photo-physical properties were recorded on UV-visible ...

Solar thermal fuels offer a closed cycle and a renewable energy storage strategy by harvesting photon energy within the chemical conformations of molecules and retrieving energy by an induced release of heat. However, the majority of reports are limited to the ultraviolet light storage, which potentially interferes with the surrounding environment and reduces the material lifetime. Here, we present a novel arylazopyrazole (AAP)-containing dendrimer that not only addresses the hindrance of visible light storage for solar thermal fuels but also exhibits outstanding performances of abundant energy conversion and stable storage, which are attributed to the substantial absorbance in visible wavelengths of para-thiomethyl-substituted AAP groups and the stability of cis isomers, respectively. The energy density of the dendrimer fuel after efficiently harvesting blue light (405 nm) is as high as 0.14 MJ kg-1 (67 kJ mol-1), and the storage half-life of the fabricated dendrimer film can reach up to 12.9 days. Moreover, the heat release of the dendrimer film can be triggered by different stimuli (light and heat). The dendrimer film displays a 6.5 °C temperature difference between trans isomers and cis isomers during green light irradiation. Our work provides a fascinating avenue to fabricate visible light storage solar thermal fuels and unlocks the possibility of developing natural sunlight storage in the future.

Formamidinium (FA)-based perovskites have demonstrated excellent advances in optoelectronics recently, but in terms of perovskite compounds, the optimal condition of their composition optimization remains controversial. Herein, we boosted the performance of perovskite light-emitting diodes (PeLEDs) in both efficiency and stability through composition and phase engineering. The low-dimensional FA2PbBr4 particles emerged and mixed with the FAPbBr3 composites when the FABr content is excessive. By regulating the phase composition in multiphase FAPbBr3 perovskites, the maximum external quantum efficiency (EQEmax) of optimal PeLEDs (5.14%) is 2.7-fold higher than that of pure FAPbBr3-based PeLEDs (1.90%), and device stability is improved. Further optimizing the film quality and emission efficiency with Rb+ ions, the EQEmax of PeLEDs can be increased to 6.01%, with a half-lifetime of about 185 s under the high current density. This strategy of phase composition optimization in FA-based perovskites provides an effective way to process high-efficiency and stable PeLEDs.

Multi-functional nanofibers are playing an important role in the optical field, and are widely used in fluorescence indication, product anti-counterfeit identification and smart clothing. Nanofibers with photoluminescence and photochromic functions are already attracting more interest from researchers. In this work, based on electrospun technology, the modified-PMMA nanofibers[PMMA=poly(methyl methacrylate)] with photoluminescence and photochromic functions were prepared through the design of the sheath-core structure(SCNFs 1–4). Compared with other samples, SCNF-4 shows outstanding photoluminescence and photochromic functions. SCNF-4 can produce green light and its fluorescence intensity and fluorescence lifetime can reach 7144 a.u. and 1031.32 µs, respectively. In photochromic functions, SCNF-4 can show purple in 1 min under the 365 nm ultraviolet light, and the color can be preserved for more than 4 h under the sunlight. When SCNF-4 is irradiated by far infrared light, the color of the samples can fade quickly in 40 s. Under the irradiation of ultraviolet light of different wavelengths, SCNF-4 can display multi-color fluorescence and achieve a reversible transition between white and purple. The design of the sheath-core structure realizes the complementarity of photoluminescence and photochromic functions of the electrospun modified-PMMA nanofibers, which is important to promote the wide application of multi-functional nanofibers in the optical field.

Epilepsy is a problematic neurological disorder combined with recurrent seizures, and gabapentin is a vital antiepileptic drug proposed for the treatment of many neuropathic pains. However, the bioavailability of this drug decreases with enhancing dose and may alter the central nervous system and induces different side effects. Therefore, design and fabrication of visible-light sensitive nanocarriers for this drug are being demanded in the few past years. Herein, gold and silver nanoparticles are synthesized through the simple Turkevich method and characterized by TEM, DLS, XRD and UV–Vis techniques. The XRD and TEM analyses confirmed formation of the face-centered cubic Au and Ag crystalline phases with 20–30 nm in size. Then, the prepared nanoparticles are used as drug-loadable nanospheres (DLNs) for gabapentin in an aqueous colloidal solution. It is found that the characteristic surface plasmonic resonance (SPR) peaks of the DLNs loaded with gabapentin (DLNs-LG) are strongly dependent on the concentration of the loaded drug. Moreover, the SPR and drug-release behavior of the DLNs-LG are investigated upon three different light sources (red, green, and blue). The obtained results show that the most efficient way to release the maximum amount of drug is to adopt the wavelength of the light source with the SPR peak of the synthesized DLNs-LG. A sensible hypsochromic blue shift is also observed by increasing the irradiation time on the DLNs-LG NPs, establishing the time-dependent nature of the drug-release process. Moreover, the performed numerical calculations exhibit interesting information on the loading and release processes and an equation is finally derived to qualitatively evaluate the amount of the detached drug from DLNs-LG NPs. Furthermore, it is found that the green light is favored for Au NPs; whereas the blue LED source is preferred for Ag NPs to achieve the best release efficiency. The outputs of this study can be useful to understand the influence of light irradiation on the drug-loaded nanoparticles in order to introduce a new method to study drug release/loading mechanisms onto Au and Ag NPs.

A series of green light-emitting Ba5Zn4Y8O21:Er3+ nanophosphors were prepared via single-step solution combustion process. PXRD-Rietveld investigation revealed that Er3+ ions are well-substituted Y3+ ions and no major change was observed in the crystalline structure of pure host matrix. Tetragonal nanoparticles with almost no agglomeration were revealed by morphological analysis. Different elements present in the prepared nanomaterials were elucidated via EDAX mapping. Photoluminescence investigation of Ba5Zn4Y8O21:Er3+ nanophosphors displayed an intense green emission peak of Er3+ ions credited to 4S3/2 → 4I15/2 transition, under NUV excitation of 379 nm. The concentration quenching occurred after 2.0 mol% concentration of the Er3+ ions in Ba5Zn4Y8O21 host, thus apprehended it an optimized concentration. CIE coordinates (x, y) of all the prepared nanocrystalline phosphors lied in the green region. Bandgap (Egap) values of the optimized sample were calculated by analysing the DR spectra of that sample which are found to be 4.0 eV for the pure host and 3.9 eV for the doped sample which lie in semiconductor range. The brief description of all these results proves the importance of synthesized nanophosphors in R-G-B (red–green–blue) PC white light-emitting diodes (WLEDs).

The photoinduced synthesis of zinc oxide nanoparticles (ZnO NPs) was carried out to unveil the effects of change in wavelength of photons. ZnO NPs were synthesized by the coprecipitation technique exposed to different light regimes [dark environment, daylight, and blue-, green-, yellow-, and red-colored light-emitting diodes (LEDs)] at room temperature. X-ray diffractogram (XRD) revealed the wurtzite structure of ZnO NPs. A small change in the size of ZnO NPs (17.11-22.56 nm) was observed with the variation in wavelength of lights from 350 to 700 nm. Spherical to hexagonal disks and rodlike surface morphologies were observed by scanning electron microscopy (SEM). The elemental composition and surface chemistry of NPs were studied by energy-dispersive X-ray diffractive (EDX) and Fourier transform infrared (FTIR) spectra. Maximum free radical quenching activity, cation radical scavenging, and total antioxidant capacity were found in ZnO NPs synthesized under green light (28.78 ± 0.18, 30.05 ± 0.21%, and 36.55 ± 2.63 μg AAE/mg, respectively). Daylight-synthesized NPs (DL-ZNPs) showed the greatest total reducing potential (15.81 ± 0.33 μg AAE/mg) and metal-chelating activity (37.77 ± 0.31%). Photoinduced ZnO NPs showed significant enzyme inhibitory effects on amylase, lipase, and urease by red-light NPs (87.49 ± 0.19%), green-light NPs (91.44 ± 0.29%), and blue-light NPs (92.17 ± 0.34%), respectively. Photoinduced ZnO NPs have been employed as nanozymes and found to exhibit intrinsic peroxidase-like activity as well. Blue-light-synthesized ZnO NPs displayed the strongest antibacterial activity (23 mm) against methicillin-resistant Staphylococcus aureus (MRSA). This study can be considered as a novel step toward the synthetic approach using LEDs to synthesize ZnO NPs with specific physicochemical properties and extends a great prospect in the environmental chemistry, food safety, and biomedical fields as nanozyme, antioxidant, antibacterial, anti-α-amylase, antiurease, and antilipase agents.

Herein, we report a facile, ultrasensitive, and selective fluorescence turn-on sensing strategy based on green-light-emitting functional nanodots for the detection of bacterial lipopolysaccharide (LPS) endotoxin. In this protocol, first, the pure carbon dots (CDs) with a fairly high quantum yield were prepared by microwave-assisted pyrolysis of citric acid in the presence of urea. Subsequently, the carboxyl-group-rich surfaces of the CDs were allowed to conjugate with the poly-l-lysine (PLL) using an EDC-NHS amidization method to obtain the PLL-modified CDs (PLL-CDs). The LPS could specifically bind to the PLL at the PLL-CD surfaces, and this binding enabled an electron transfer from the phosphate groups of LPS to the carbon core through the PLL bridge, thus resulting in a fluorescence enhancement. Interestingly, this fluorescent turn-on sensor provided a detection limit of 68.3 fM in PBS (pH 7.4), which is the lowest ever reported among all of the synthetic assays for LPS detection. Furthermore, our fluorescent probe was able to show a remarkable selectivity toward LPS over a range of commonly known interfering substances. Thus, this study demonstrated the feasibility of using specific LPS binding to PLL to drive molecular recognition in aqueous medium and offered an effective fluorescence turn-on sensing strategy to detect bacterial endotoxin in diverse clinical and biological applications.

In this paper, Er3+, Yb3+:CeF3 nanoparticles of different sizes were successfully prepared via the hydrothermal method. The effects of Yb3+ ion concentration and the size of nanoparticles on the up-conversion luminescence performance of the materials were investigated through X-ray diffraction, scanning electron microscopy, infrared absorption spectroscopy, and photo luminescence spectroscopy. It was found that these nanoparticles show excellent up-conversion luminescence under a 980 nm laser excitation. The green and red emissions at 517 nm, 543 nm, and 654 nm were, respectively, attributed to the following radiation transitions of the Er3+ ions: 2H11/2 → 2I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2. Furthermore, the emission intensity of the red light was significantly stronger than that of the green light. As the nanoparticles size increased, the luminescence intensity of the samples was significantly reduced. These results demonstrate the great potential of Er3+, Yb3+:CeF3 nanoparticles in bio-imaging, luminescent, anti-counterfeiting, and photocatalysts.

The films of alizarin yellow GG (AYGG)–CuCl2 blended with polyvinyl alcohol (PVA) have been successfully synthesized by casting method. The results show that the dielectric properties of AYGG–Cu(II) blended with PVA are enhanced by lowering selected frequency while σac(ω) increases monotonically with frequency, acting in accordance with the correlated barrier hopping model. At low temperature, the DC electrical resistivity of AYGG–Cu(II) blended with PVA film is temperature independent, while it is decreasing with high temperature. Al/(AYGG – Cu(II) blended with PVA)/ITO is fabricated as organic photovoltaic cell, concluding that there are many mechanisms can control the current flow. Al/(AYGG – Cu(II) blended with PVA)/ITO solar cell under illumination of green light be most effective compared to illuminations of others. It is concluded that Al/(AYGG – Cu(II) blended with PVA)/ITO solar cell is very important, with potential advantages such as low cost and low-temperature fabrication processes. It is recommended that this material can be used in different applications such as temperature sensors, inrush current limiters, thermistors, and NO2 sensor.

A new green-emitting phosphor, KAlSiO4:1.5 mol% Tb3+, x mol% Li+, was prepared via a high-temperature solid-phase method, and its crystal structure, diffuse reflectance spectrum, and luminescence were studied. The results show that the Li+ doping shifts the strongest diffraction peak to a high angle direction, reducing grain size by 11.4%. The entry of Li2CO3 improves the luminescence performance of KAlSiO4:1.5 mol% Tb3+. At a Li+ concentration of 1.5 mol%, the sample has strong absorption in the ultraviolet light range from 250 to 400 nm. The luminous intensity of the sample at 550 nm approximately quadruples after Li+ doping. Additionally, the colour purity of the sample and the internal quantum yield increase to 83.3% and 42%, respectively. The sample changes colour with time when exposed to air without an obvious fading phenomenon. The emission intensity at 200 °C is 95.1% of its value at room temperature, indicating that the phosphor has excellent thermal stability when x = 1.5. These results show the feasibility of using the silicate phosphor for generating the green light component of white light-emitting diodes for solid-state lighting.

金沢大学先端科学・社会共創推進機構, To produce a deep green (530 nm–570 nm) LED, the suitable indium (In) composition in the InxGa1-xN/GaN multi-quantum well (MQW) structure is crucial because a lower indium composition will shift the wavelength of emission towards the ultraviolet region. In this paper, we clarify the effects of an indium-rich layer to suppress such blue shifting, especially after the annealing process. According to characterizations by the uses of XRD and TEM, narrowing of the MQW layer was observed by the indium capping, while without the capping, the annealing results in a slight narrowing of MQW on the nearest layer to the p-type layer. By adding an indium capping layer, the blue shift of the photoluminescence was also suppressed and a slight red shift to keep green emission was observed. Such photoluminescence properties were consistent with the tiny change of the MQW as seen in the XRD and TEM characterizations.

The Sonogashira coupling of 1,3,6,8-tetrabromopyrene with 4-[(–)-β-citronellyloxy]phenylethyne was employed to synthesize 1,3,6,8-tetra[4-(citronellyloxy)phenylethynyl]pyrene. The pyrene derivative catalyzed the reductive desulfonylation of ethenyl sulfones via visible-light irradiation (514 nm green light-emitting diodes) in the presence of i-Pr2NEt. The β-citronellyloxy groups provided the sufficient solubility to the highly π-expanded pyrene catalyst, and their polar oxygen functionalities enabled the easy separation of the catalyst from the products via column chromatography.

Newly long afterglow phosphor-in-glass (PiG) plays pivotal roles in the region of optical data storage. By using solid-phase reactions and unique spectrum modulation methods, a color-tunable PiG with decent persistent phosphorescence which can be tuned from green to blue has been fabricated. Lu3Al2Ga3O12: Ce3+, Cr3+ (LuAGG: Ce3+, Cr3+) based on TBZNA glass could emit bright green light signal located at 350 and 420 nm ascribed to the 5d1/5d2-4f transitions when corresponding optical data was being loadout. The doping of Cr3+ increases the density of the trap and provides additional traps between the shallow trap and the deep trap to capture more electrons, further improving afterglow decay time. And the storage time and cyclic reading times are derived by the method of thermal stimulation. Thereinto, tunable emission color has been obtained via changing the concentration of Ga3+, using UV excitation. Moreover, the influence of the Cr3+/Ga3+ on luminescence properties of long-afterglow-PiG materials have been described in detail. Achieved results confirm that it makes LuAGG-PiG as a long afterglow PiG matrix, demonstrating its promising application in optical data storage.

In ultracompact image displays based on metasurfaces, the image color is usually controlled by varied nanostructure dimensions, which requires elaborate design and precise manufacturing of nanostructures. Here, we present a metasurface composed of equal-sized nanostructures to control the color of output light, simply by polarization control. Specifically, with resonances occurring in two orthogonal axes for different wavelengths, each nanostructure of the metasurface acts as a biaxial nano-polarizer and reflect most of incident red and green light polarized along the long and short axes, respectively. Hence, by means of reconfiguring the orientations of the biaxial nano-polarizers, the mixture of red and green light with different intensity ratio, governed by Malus law, can be employed to generate a pseudo-colored nanoprinting image. We experimentally demonstrate the proposed metasurfaces by successfully encoding and decoding pseudo-color nanoprinting images right at the metasurfaces. With advantages such as flexible image display and ultra-simple nanostructure design, the proposed dichroic polarizing metasurface can promote advanced research of metasurfaces in color control, ultracompact image display, pseudo-color processing, and many other related fields.

A novel green-emitting Er3+ doped SrLaAlO4 phosphor has been synthesized successfully through one-step calcination of the precursor prepared by co-precipitation method. Meanwhile, the electronic structure and photoluminescence (PL) properties of the samples are investigated in detail. It is found that the strongest excitation peak among the several narrow excitation bands from 250 nm to 500 nm locates in near-UV region, indicating that the phosphor can match well with not only blue LED chips but also near-UV LED chips. Under the excitation of 377 nm light, the SrLaAlO4 phosphor can emit bright green light peaking at 527 nm and 548 nm simultaneously. In addition, the different responses of the two emission positions to temperature variation of SrLaAlO4:Er3+ phosphor have been verified and expounded. The temperature sensing properties of SrLaAlO4:Er3+ in a wide range of 298–573 K show a good exponential function relationship between ratiometric intensity and temperature (R2 > 0.999) as well as a high sensitivity (1.42% K− 1). Besides, the CIE coordinates diagram shows that this phosphor has an outstanding color stability. In view of the outstanding performance in the PL, thermal stability and sensitivity, SrLaAlO4:Er3+ phosphor can be promisingly applied in near ultraviolet converted white light LED devices (wLEDs) and optical thermometry.

Two different device structures are numerically studied, and their optoelectronic characteristics with standard structure are compared. The authors minimized the uneven carrier distribution across the active region. By replacing the first quantum barrier with graded AlGaN and using a graded AlGaN electron blocking layer, in the structure proposed by the authors, the injection of holes into the active region is improved. By using the graded AlGaN barrier, the concentration of injected electrons is also controlled because of the additional barrier height. As a result, the contribution of radiative recombination is boosted. The droop ratio of the proposed structure is reduced to ∼34% at 100 A cm−2 in comparison to other devices.

An antimony based luminescent organic–inorganic hybrid compound H3SbCl6(L)6 (1, L = 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate) has been prepared by the solvothermal method. It emits bright green light peaking at 525 nm, with an internal quantum yield (IQY) of 73% under 360 nm excitation. The negative thermal quenching (NTQ) effect has been observed in the temperature range of 77 K to 297 K. Due to its ionic structure, compound 1 is soluble in numerous organic solvents, including methanol, dimethyl sulfoxide (DMSO), etc. The solution processability combined with high quantum efficiency makes 1 a promising candidate as a luminescent coating material for optoelectronic devices.

Dye-semiconductor assemblies are very versatile visible light photocatalysts in terms of tunability by tweaking either dye molecules or semiconductor materials. Here, we adopted a strategy of molecular inverse design of alizarin red S (ARS) to identify the blueprint underlying the superior photocatalytic activity of ARS-TiO2 assembly. We discovered that the substituted -OH groups of anthraquinone provide visible light absorption and binding sites. Importantly, the molecular features of 1,2-dihydroxyanthraquinone (1,2-DHA) contributes mostly to the unique photocatalytic activity after binding with TiO2 with broad visible light absorption which can be maintained at high concentration of amines. Moreover, the electron-withdrawing effect of -SO3-Na+ groups increase the acidities of substituted -OH groups, leading to stronger binding and subsequent higher activity. Ultimately, in situ formed 1,2-DHA-TiO2 assembly can be a powerful photocatalyst for green light-induced selective oxidation of amines into imines with aerial O2. This work makes evident the promise of molecular design in tailoring dye-semiconductor assemblies for visible light-induced photocatalytic selective chemical transformations.

Metal halide perovskites are emerging materials for next-generation optoelectronic devices, of which the all-inorganic CsPbBr3 perovskite has attracted increasing attention due to its outstanding stability and excellent photoelectric characteristics compared with organic–inorganic counterparts. However, the electroluminescence (EL) efficiencies of inorganic CsPbBr3 perovskite light-emitting diodes (PeLEDs) are unsatisfactory because of high trap densities, which lead to non-radiative recombination loss. Herein, by introducing potassium bromide (KBr), we successfully prepare zero-dimensional/three-dimensional (0D/3D) Cs4−xKxPbBr6/CsPbBr3 heterostructure perovskite films with suppressed trap density and improved photoluminescence quantum yield (PLQY). The deep energy level of 0D Cs4−xKxPbBr6 phase is confirmed using DFT calculation. Moreover, the formation of the unique heterostructure inhibits the free charge diffusion at the grain boundary from suffering trapping and recombination, which facilitates efficient radiative recombination in the 3D CsPbBr3 phase. Therefore, the optimized green PeLEDs show a high external quantum efficiency (EQE) of 12.8%, which is a six-fold improvement over the pristine one (2.1%), and a maximum brightness of 39 400 cd m−2. Our work provides a rational charge carrier confinement strategy for developing high-performance PeLEDs and can be broadened to other potential perovskite materials, not restricted to the CsPbBr3-based perovskite films.

All-inorganic lead halide perovskite nanocrystals (NCs) have been promising candidates in various optoelectrical fields. It is still challenging to further enhance their optical properties and stability to meet the requirements of practical applications. Herein, we develop a passivation strategy towards CsPbBr3 NCs by using inorganic phosphate and bromide anions. Phosphate can coordinate with lead ions on CsPbBr3 NCs as capping ligands; meanwhile, excess bromide can strengthen the repair of surface trapping sites. The treated NCs exhibit near-unity quantum yield and boosted radiative recombination. In addition, obvious enhancement has been realized in their durability against polar solvents. A white light emitting diode (WLED) has been fabricated by employing the passivated NCs as a green light source, which possesses high luminous efficiency and operational stability.

Visible light-triggered reversible triazolinedione (TAD) chemistry was already reported in the 1970s but it has only recently been introduced into the field of materials science, and as such remains relatively unexplored. Here, we exploit the reversible naphthalene-TAD Diels–Alder couple to crosslink pre-synthesized polymers in a precipitation-like polymerization to form narrow disperse microparticles. The approach does not require additives such as stabilizers or initiators and proceeds to deliver particles under relatively mild conditions in less than 1 h. While the crosslinked particles maintain their shape upon continuous irradiation with green light, the particles can be readily degraded in the dark at ambient temperature through a spontaneous cycloreversion process. In addition, the formation and degradation rate can be tuned by employing shorter or longer prepolymers, with particles synthesized from larger polymers degrading slower compared to their shorter polymer counterparts. The particle formation, light-stabilization and degradation were characterized in-depth by scanning electron microscopy (SEM) and online static light scattering experiments. In particular the particles’ tuneable intrinsic degradation behaviour could hold key potential, for instance, in long term drug or fertilizer delivery systems.

The auxiliary light equipment for plant growth requires phosphor-converted light-emitting-diodes (pc-LEDs) with high luminous efficiency and a stable structure, and the properties of phosphors highly determine the performance of the pc-LEDs. This work reports a deep-red emitting phosphor with an ultra-wide response range which is regarded as CaMgAl10O17:Mn4+. The absorption range spans the ultraviolet, near-ultraviolet, blue, and green light regions from 250 to 550 nm. Under the excitation of the best excitation position at 343 nm, deep-red light at 654 nm is emitted, and the quantum efficiency is as high as 86.7%. The luminous efficiency of the two pc-LED devices prepared based on CaMgAl10O17:Mn4+ with 395 and 460 nm chips reached 54.3 and 59.6 lm W-1, respectively. The spectra of the two pc-LEDs exhibit high resemblance to the absorption spectra of chlorophyll A and B in plant growth photosynthesis. These indicate that the CaMgAl10O17:Mn4+ phosphor can be an excellent candidate for plant growth LED light.

The upconversion of manganese (Mn2+) exhibits a green light output with a much longer lifetime than that of lanthanide ions, showing great potential in the frontier applications like information security and anti-counterfeiting. Mn2+ can be activated by energy migration upconversion. However, there exists serious quenching interactions between Mn2+ and the lanthanides at the core–shell interfacial area, which would markedly reduce the role of Tm3+ as a ladder to facilitate the up-transition and subsequently limit the upconversion of Mn2+. Here, we propose a mechanistic strategy to enhance the upconversion luminescence of Mn2+ by spatial control of energy migration among Gd sublattice through introducing an additional migratory NaGdF4 interlayer within the commonly used core–shell nanostructure. This design can not only isolate the interfacial quenching interactions between the sensitized core and luminescent shell, but also allow an efficient channel for energy transport, resulting in enhanced upconversion of Mn2+. Moreover, the relatively long lifetime of Mn2+ (around 32.861 ms) provides new possibilities to utilize the temporal characteristic for the frontier application of multi-level anti-counterfeiting through combining the time-gating technology.

A typical solution-processed perovskite film possesses numerous defects, especially when fabricated under high-humidity ambient conditions, which severely limits the performance of planar perovskite solar cells (PSCs). Here, the unique fluorescent dye molecule additive of 3-(2-benzimidazolyl)-7-(diethylamino)-coumarin (8GFF) is introduced into a perovskite film to address the defect issues. With the addition of 8GFF, its functional groups (–COO) can interact with Pb2+ ions, thereby minimizing the ionic defects in the perovskite film and improving its crystalline quality. And the optimized charge transport with decreased recombination loss can also be realized. Besides, the introduction of 8GFF increases the absorption capacity of the device in a green light wave band, beneficial for photocurrent enhancement. Consequently, the device fabricated in an air environment without a glove box exhibits a promising efficiency of 19.16%, superior to 15.61% of the control device. This work demonstrates the potential applications for fabricating high-performance planar devices regarding the aspects of fluorescent dyes.

2-Dimensional semiconductor SnS2 has emerged as one of the most prospective candidates for chemoresistive gas sensor applications due to its outstanding gas sensing performance. Herein, we propose the room temperature nitrogen dioxide (NO2) sensing of SnS2 nanoflowers (NFs) enabled by visible light activation. SnS2 NFs were successfully prepared by solvothermal synthesis with abundant edge sites. The high absorbance in the visible light region triggered the generation of charge carriers resulting in decreased resistance and enhanced gas sensing characteristics. Even under red light and green light with low photon energy, the room temperature NO2 sensing performance was improved. The highest NO2 sensing performance was accomplished under blue light, including the highest response, excellent selectivity towards NO2 and an extremely low detection limit. Moreover, the sensor exhibited reliable gas sensing performance in humid conditions and maintained its properties after long-term relaxation. Taking advantage of surface properties, optical properties and gas sensing properties, a light-activated SnS2 NF based gas sensor is anticipated to further develop SnS2 nanostructures for use in an electronic nose.

The luminescence of dielectric phase transition materials is one important property for technological applications, such as low-energy electron excitation. The combination of dielectric phase transitions and luminescence within organic–inorganic hybrids would lead to a new type of luminescent dielectric phase transition multifunctional material. Here, we report two novel A2BX4 organic–inorganic hybrid complexes [Me3NVinyl]2[MnCl4] 1 and [Me3NVinyl]2[MnBr4] 2, ([Me3NVinyl] = trimethylvinyl ammonium cation). The complexes 1 and 2 were found to undergo continuous reversible phase transitions as well as switch dielectric phase transitions. Strikingly, intensive red luminescence and green luminescence were obtained under UV excitation respectively to reveal potential application of the two complexes in multi-functional materials along with dielectric switches and so on.

In this report, we have proposed a novel ribbon-FTM method to develop highly oriented polymer thin films. A donor–acceptor (D-A) type copolymer, PCPDTBT has been selected as the target material for investigation. The maximally oriented film showcased a DR of 4.1. Highly aligned polymer film was used as the active layer for the development of bottom gate bottom contact (BGBC) type OFETs. An average mobility and an Ion/Ioff of 0.002 cm2/Vs and 5 × 103 were obtained under dark conditions, respectively. Upon illumination with monochromatic green light (λ = 522 nm, Pin = 0.5 mW/cm2), the OPTs showcased a high photosensitivity and responsivity of 103 and 17 A/W, respectively. The obtained values were found to be superior over many of the previously reported similar OPTs which employed other organic polymers. The results thus are of crucial significance with respect to the development of facile, cost effective and highly sensitive single polymer thin film based OPTs.

The post-infrared (post-IR) pulsed blue light stimulated luminescence (PBLSL) signal has been employed to determine the equivalent dose (D e ) of feldspar contaminated quartz grains, but it sometimes suffers from the interference of feldspars. Since the green light stimulated luminescence (GLSL) signal of feldspars might be more reduced by a prior IR stimulation, we compared the characteristics of post-IR PBLSL and post-IR pulsed GLSL (post-IR PGLSL) signals of quartz and feldspars in this study to evaluate the feasibility of employing the green light for pulsed stimulation. We investigated the effect of the signal integration period, pulsed stimulation temperature, and prior IR stimulation temperature on the intensities of post-IR PBLSL and post-IR PGLSL of quartz and feldspars, and evaluated the potential feldspar interference on these two signals for the hypothetical and artificial quartz-feldspar mixture. The results demonstrate a lower feldspars contribution for the post-IR PGLSL signal. The feldspar interference only slightly increases with the increase of integration period for the post-IR PGLSL signal measured at low stimulation temperature, which permits a long integration period to be employed to enhance the signal to noise ratio. This study shows that the green light is a promising alternative for pulsed stimulation to suppress the feldspar contribution.

Considering porous materials as host matrices is an elegant way to enable photoswitching of non-covalently attached organic dyes even in the solid state. By focusing on the resulting optical properties as a function of loading degree and synthesis procedure, the occurring host–guest and guest–guest interactions can be determined and further exploited. In the course of this study, the photochromic behavior of ortho-tetrafluoroazobenzene (tF-AZB) inside flexible DMOF-1 was investigated from these points of view. It was found that depending on the loading degree and temperature, tF-AZB shows varying E/Z ratios and switching efficiency. For systems with low loading, reversible visible light induced isomerization was observed over ten switching cycles: Upon violet light exposure, formation of 100% E isomer was generated, while green light irradiation resulted in ∼60% Z-tF-AZB. Complementary molecular dynamics simulations at DFTB (density functional tight binding)-level revealed changing binding sites for Z-tF-AZB inside DMOF-1. For the E isomer, only low oscillations have been found, which in turn display a rare T-stacking interaction. Although the interaction strengths of the E and Z isomers with DMOF-1 are in the same range, the different mobility of both isomers due to varying binding sites explains the preference of the E isomer even upon green light exposure.

The stability of perovskite quantum dots (PQDs) plays a vital role in practical devices. Besides silica coating, embedding PQDs in zeolites is another strategy to improve their stability significantly. Although the zeolite rigid framework has been reported to protect PQDs, there are few reports on the in situ synthesis of PQDs in zeolites. In this work, cubic phase CsPbX3 (X = Br, I) nanocrystals were successfully prepared by the ion exchange method combined with a non-polar organic trigger. Dropping a certain amount of ZnM2 (M = Br, I) solution into the intermediate product Cs4PbCl6 nanocrystals resulted in the formation of the final CsPbX3 nanocrystals. The ZnM2 solutions were prepared in non-polar solvents (hexane, octane, or chloroform). The highest photoluminescence quantum yield (PLQY) of the synthesized CsPbX3@zeolite composites can reach 83%, with a lifetime of 1.37 μs. The stability of the CsPbX3@zeolite composites thin film against damage from air and light is significantly improved. We fabricated white light-emitting diodes (WLEDs) using CsPbBr3@zeolite as the green light source and CsPbI3@zeolite as the red light source to further emphasize the practical application effect of the CsPbX3@zeolite composites. This work not only provides a new method for the synthesis of CsPbX3 nanocrystals but also involves the in situ synthesis of high stability CsPbX3@zeolite composites within the zeolite.

An ultrapure green phosphor with narrow emission range (525–535 nm) and full width at half maximum (FWHM < 25 nm) is critical for a backlit light-emitting diode to realize an ultrawide color gamut in liquid-crystal display (LCD), according to the Rec. 2020 standard. However, it is extremely formidable to achieve this goal for low-dimensional halide perovskites (LDHPs), which readily display broadband emissions arising from self-trapped excitons due to strong electron–phonon coupling. Herein, we report a new one-dimensional (1D) hybrid lead halide of [TMPDA]2Pb3Br10 (TMPDA = tetramethyl-1,3-diaminopropane) displaying unusual ultrapure green light emission. Benefiting from the synergistic work of weak electron–phonon interaction and strong quantum confinement, this 1D halide displays sharp green emission at 526 nm with narrow FWHM (25 nm), high photoluminescence quantum yield (71.95%) and color purity (91.1%), which achieves the Rec. 2020 standard and represents the purest green emitting LDHP to date. Remarkably, as a down-conversion green phosphor, [TMPDA]2Pb3Br10 provides an ultrawide color gamut covering 121.5% of NTSC and 90.7% of Rec. 2020 standards, showcasing the application in high-resolved LCD. The establishment of a fundamental structure–property relationship also paves a new way to rationally design novel narrow-band emitting LDHPs as a supplement of colloidal 3D perovskite nanostructures.

Lead-free, non-toxic transition metal-based phosphorescent organic–inorganic hybrid (OIH) compounds are promising for next-generation flat-panel displays and solid-state light-emitting devices. In the present study, we fabricate highly efficient phosphorescent green-light-emitting diodes (PHOLEDs) using the lead-free, non-toxic, zero-dimensional OIH compound [(H2CCHCH2)(C6H5)3P]2MnBr4 (1), which exhibits an emission peak at 516 nm and a long lifetime of 441 μs. The long lifetime indicates the phosphorescent emissive nature of 1. Density functional theory calculations confirm that the narrow green emission from 1 is due to the highly localized electronic states of the valence and conduction bands. A flexible green-light-emitting phosphorescent substrate is successfully fabricated from 1 using a nylon membrane, indicating that 1 has a significant potential for use in flexible optoelectronic devices. By engineering the organic hole and electron transport layers, we achieve a highly efficient all-vacuum-deposited PHOLED with a current efficiency of 24.71 cd A−1, a power efficiency of 20.61 lm W−1, and an external quantum efficiency of 7.12%. Together, our findings will pave the way for the development of high-performance Mn(II)-based LEDs.