Search

Up-converted self-trapped exciton luminescence via seven-phonon absorption in the Na/Bi-alloyed Cs2AgInCl6 lead-free double perovskite is reported.

A white LED backlit unit designed by coupling a CsPbBr3@glass@PDMS green film and Mn4+:K2SiF6 red film with a home-made blue light guide panel endows a liquid crystal display with a wide color gamut.

The development of advanced luminescent materials is highly desirable for addressing the rising threat of forgery.

Exploring highly efficient near-infrared (NIR) emitting materials is desirable for the advancement of next-generation smart NIR light sources. Different from most reported Cr3+-doped emitters with far-red emissions, Yb3+-activated phosphors are expected to yield pure NIR (∼1000 nm) light. Herein, a new hot-injection route using all metal-oleate salts to fabricate Yb3+-doped CsPbCl3 perovskite nanocrystals (PeNCs) is reported for the first time, which produce PeNC-sensitized Yb3+ NIR emission with photoluminescence quantum yields (PLQYs) higher than 100%. With the help of temperature-dependent PL spectra, femtosecond transient absorption spectra, and time-resolved PL spectra, it is evidenced that the in situ produced intrinsic shallow trap states in a CsPbCl3 host play a key role in facilitating the picosecond nonradiative cooperative energy transfer from PeNCs to two Yb3+ dopants simultaneously. Using the optimized Yb3+:CsPbCl3 quantum cutters, a phosphor-converted NIR light-emitting diode (pc-NIR-LED) is fabricated, exhibiting an external quantum efficiency of 2%@28 mA, a high NIR output irradiance of 112 mW/cm2@400 mA, and excellent long-term stability. Finally, the designed pc-NIR-LED is demonstrated to have great potential as an invisible night-vision light source.

New antiviral influenza treatments can effectively alleviate illness while reducing viral shedding. However, how such effects can translate into lower population infections of seasonal influenza in China remains unknown. To shed light on the public health impacts of novel antiviral agents for influenza, we constructed a dynamic transmission model to simulate the seasonal influenza epidemics in China. Two antivirus treatments, baloxavir and oseltamivir, were evaluated by estimating their impacts on the incidences of influenza infection in a single flu season. In the base-case analysis of a 10% antiviral treatment uptake rate, 2760 and 3420 per 10 000 persons contracted influenza under the treatment of baloxavir and oseltamivir, respectively. These incidence rates amounted to an 18.90% relative risk reduction (RRR) of infection associated with baloxavir in relation to oseltamivir. The corresponding RRR was 82.16% when the antiviral treatment uptake rate was increased to 35%. In addition, the peak of the prevalence of infected individuals per 10 000 persons under the baloxavir treatment was 177 (range: 93-274) fewer than that of oseltamivir. Our analyses suggest that the baloxavir treatment strategy reduces the incidence of influenza in China compared with oseltamivir in the setting of a seasonal flu epidemic. Also, increasing the uptake rate of antiviral treatment can potentially prevent millions of infections during a single flu season.

Signal transducers and activators of transcription 1 (STAT1) is an important transcription factor that regulates the growth, survival, differentiation and apoptosis of various tumor cells. However, the biological roles of STAT1 and potential mechanisms in triple-negative breast cancer (TNBC) remain largely unknown. The expression levels of STAT1, CircIFI30, CDCA4, and epithelial-mesenchymal transition (EMT)-associated molecules (MM2, MMP9, E-cadherin, and N-cadherin) were evaluated using quantitative reverse transcription polymerase chain reaction (RT-qPCR). Furthermore, cell-counting kit-8 assay, Transwell assay, flow cytometry, and immunofluorescence staining were performed to investigate the biological functions of STAT1 and CircIFI30 in TNBC cells. In addition, Dual luciferase activity assay and chromatin immunoprecipitation qPCR were used to predict the interaction between STAT1 and CircIFI30 promoter. The effects of CircIFI30 on the stability of CDCA4 mRNA were also confirmed in further function study. Up-regulation of STAT1 was detected in TNBC tissues and cells, which were positively correlated with tumor metastasis, advanced clinical stage and poor survival rate. Up-regulated STAT1 could promote the proliferation, invasion, migration, EMT and inhibit the apoptosis of TNBC cells. RNA-seq indicated has_circ_0005571 (CircIFI30) was significantly down-regulated in TNBC cells after knockdown of STAT1. Moreover, STAT1 could be novel transcription factor that binds to CircIFI30 promoter to enhance its transcription. Additionally, knockdown of CirclFl30 down regulated the expression of cell division cycleassociated protein 4 (CDCA4) through reducing the stability of its mRNA. Our data revealed the STAT1/CircIFI30/CDCA4 axis could regulate the proliferation, invasion, migration, EMT and apoptosis of TNBC cells. Therefore, STAT1 may be a putative therapeutic candidate for targeted treatment of TNBC.

This work reports a novel dual-phase glass containing Tm:NaYbF4 upconverting nanocrystals (UCNCs) and CsPbBr3 perovskite nanocrystals (PNCs). The advantages of this kind of nanocomposite are that i...

The development of luminescent materials with concurrent tunable spectral profile and brightness is a great challenge to improve the security of the authentic items and shield against counterfeiting. Herein, we report the realization of in situ hexagonal-to-cubic phase transition of Yb/Er:NaLuF4 nanocrystals inside inorganic glass via simply modifying the heating (glass crystallization) temperature, leading to simultaneous control of upconversion emission color and intensity. Impressively, this peculiar phase transition process is reversible upon cyclic heating/cooling thermal-treatment and the accompanying repeatable upconversion emission behaviors are retained. It is experimentally demonstrated that multiple patterns visualized using screen-printing inks containing the investigated samples and the anti-counterfeiting prototypes are practically applicable by switching in situ glass crystallization temperatures. These findings show great promise of the designed lanthanide-doped NaLuF4@glass nanocomposites in high-level anticounterfeiting applications and give new insights for the development of advanced optical materials.

The present study evaluated the real-world effectiveness of influenza and pneumococcal dual-vaccination among Chinese elderly, the evidence on which was absent. Outpatient and inpatient claims databases from Jan 1, 2015 to Apr 1, 2017 of persons at least 60 years old in Shenzhen, China were merged with electronic records of influenza vaccines and 23-valent pneumococcal polysaccharide vaccines (PPSV23) from Oct 1, 2016 - May 31, 2017. Individuals who were vaccinated with influenza between Nov 1 and Dec 31, 2016 and received PPSV23 30 days within the date of influenza vaccination were defined as the vaccinated group. A control group consisted of individuals that received neither of the vaccines was constructed by matching on year of birth, sex, and district. The two outcomes were all-cause and acute respiratory hospitalizations. Difference-in-difference (DiD) logistic regressions that were proceeded with an entropy balancing (EB) process were used to analyse the effectiveness of dual-vaccination. A total of 48,116 eligible individuals were identified in the vaccinated group, which were matched by 93,692 individuals in the control group. The EB-DiD analyses estimated that dual-vaccination was associated with lower short-term risks of all-cause (odds ratio: 0.59, CI: 0.55-0.63) and acute respiratory (odds ratio: 0.49, CI: 0.41-0.59) hospitalizations.

In-situ glass crystallization is an effective way to integrate lanthanide-doped upconversion nanocrystals into amorphous glass, producing bulky nanocomposites for specific applications. However, the precipitation of hexagonal NaYbF4 nanocrystals from glass is rarely reported owing to the preferred crystallization of cubic phase. Herein, phase-controllable in-situ crystallization of cubic/hexagonal NaYbF4 nanocrystals in glass is achieved via Y3+ doping. A series of structural and spectroscopic characterizations evidence the formation of Na(Yb/Y)F4 solid-solution nanocrystals in glass and the incorporation of lanthanide emitting centers (Er3+, Tm3+, Eu3+) into the crystalline lattice. Introducing high-content Y3+ dopants is beneficial to induce the crystallization of hexagonal NaYbF4 phase in glass and enables elaborated tunability of Er3+ upconversion emissive colors. Finally, a prototype upconverted solid-state-lighting device is constructed by coupling 980 nm laser with the as-prepared Er/Tm doped monolithic glasses containing Na(Yb/Y)F4 nanocrystals, producing bright upconversion white-light with luminous efficiency of 1 lm/W and energy efficiency of 0.5%.

Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels. Herein, a family of lanthanide (Ln3+) ions was successfully incorporated into a Bi:Cs2AgInCl6 lead-free double-perovskite (DP) semiconductor, expanding the spectral range from visible (Vis) to near-infrared (NIR) and improving the photoluminescence quantum yield (PLQY). After multidoping with Nd, Yb, Er and Tm, Bi/Ln:Cs2AgInCl6 yielded an ultrabroadband continuous emission spectrum with a full width at half-maximum of ~365 nm originating from intrinsic self-trapped exciton recombination and abundant 4f–4f transitions of the Ln3+ dopants. Steady-state and transient-state spectra were used to ascertain the energy transfer and emissive processes. To avoid adverse energy interactions between the various Ln3+ ions in a single DP host, a heterogeneous architecture was designed to spatially confine different Ln3+ dopants via a “DP-in-glass composite” (DiG) structure. This bottom-up strategy endowed the prepared Ln3+-doped DIG with a high PLQY of 40% (nearly three times as high as that of the multidoped DP) and superior long-term stability. Finally, a compact Vis–NIR ultrabroadband (400~2000 nm) light source was easily fabricated by coupling the DiG with a commercial UV LED chip, and this light source has promising applications in nondestructive spectroscopic analyses and multifunctional lighting.

The coronavirus disease 2019 (COVID-19) pandemic has caused severe health consequences. Though most COVID-19 deaths occurred among very old people, their life-year loss might be very large because of their life expectancy at that age.This study quantified how many years of life were lost due to COVID-19 in 34 countries. COVID-19 caused 9 to 21 years of life lost (YLL) per deceased patient. East Asia and Oceania had substantially lower per capita YLL than North America and Europe. Among all countries included, the United States had the greatest total YLL, Peru had the largest YLL per 100,000 people, and Mexico had the largest YLL per 100,000 COVID-19 patients.The YLL quantification indicated that the vulnerable population, especially the elderly, should be protected under careful public health measures to reduce their YLL. It also implied that it might be too early to lift anti-epidemic restrictions now, since the extreme disproportionate consequences (total and per-capita YLL) in different countries underscored the scrutinization over the variation in disease control strategies to optimize future disease control and prevention.

Carbon dots (CDs) as one of the most promising carbon-based nanomaterials are inspiring extensive research in optoelectronic applications. White-light-emitting diodes (WLEDs) with tunable correlated color temperatures (CCTs) are crucial for applications in white lighting. However, the development of high-performance CDs-based electroluminescent WLEDs, especially those with adjustable CCTs, remains a challenge. Herein, white CDs-LEDs with CCTs from 2863 to 11 240 K are successfully demonstrated by utilizing aggregation-induced emission red-shifting and broadening of CDs. As a result, a series of warm white, pure white, and cold white CDs-LEDs are realized with adjustable emissions in sequence along the blackbody radiation curve. These CDs-LEDs reach maximum brightness and external quantum efficiency up to 1414-4917 cd m-2 and 0.08-0.87%, respectively, which is among the best performances of white CDs-LEDs. To the best of the authors' knowledge, this is the first time that CCT-tunable white electroluminescent CDs-LEDs are demonstrated through controlling the aggregation degrees of CDs.

Exploring highly efficient near-infrared (NIR) emitting materials is desirable for the advancement of next-generation smart NIR light sources. Different from most reported Cr

Up to now, the rising edge of the upconversion process does not receive due attention. Herein, a demonstration utilizing the feature of the rising edge to practically detect the linear-velocity of an object is presented. Typically, upconversion processes with different numbers of participant photons would exhibit diversity in the rising edge. On this account, when the emitter is moving, the emission intensity ratio of different multiphoton processes will vary with changing linear-velocity, which enables accurate speed detection through spectral analysis. To illustrate this principle, in this work, the modeling and numerical simulation were first performed, and then experimental demonstration was carried out in which core-shell upconversion nanocrystals were elaborately designed and fabricated as the speed sensing probe to calibrate the speed of a homemade turnplate. It is believed that the present work will exploit a novel speed sensing method and find a new application for lanthanide-doped upconversion materials.

Yb/Ln (Ln=Er, Tm) doped TeO2-based glasses containing CsPbBr3 perovskite quantum dots were successfully prepared via in-situ glass crystallization. The nanocomposites yield typical green downshifting luminescence attributing to CsPbBr3 exciton recombination under UV excitation, and produce Er3+ green, Er3+ red and Tm3+ blue upconversion emissions under 980 nm laser excitation. Impressively, specific Ln3+ emissions will be quenched with the precipitation of CsPbBr3 in glass, enabling to finely tune upconversion emitting color. Spectroscopic characterizations evidence that the luminescence quenching is originated from non-radiative reabsorption effect induced by the precipitation of CsPbBr3 rather than energy transfers from Ln3+ to CsPbBr3. Finally, these nanocomposites are demonstrated to exhibit superior water resistance due to the effective protecting role of dense structural glass, particularly, about 95% downshifting luminescence of CsPbBr3 and upconversion luminescence of Er3+ related to pristine ones are retained after immersing the products in water up to 30 days.

Mn-doped aluminosilicate oxyfluoride glasses containing various concentrations of Sc 3+ ions were fabricated by a traditional melt-quenching method. Tunable Mn 2+ luminescence from green to red was achieved with increase of Sc 3+ doping content. A series of structural and spectroscopic characterizations evidenced that the Sc 3+ dopants can induce the conversion of partial green-emitting [MnO 4 ] tetrahedrons into red-emitting [MnO 6 ] octahedrons in the glasses. This is attributed to the high cation-field-strength feature of Sc 3+ ions in glass, which enables them to capture O 2− from [SiO 4 ] and [AlO 4 ] tetrahedrons. Accordingly, it was demonstrated that the Mn 2+ luminescence can be easily controlled by modifying lanthanide dopants (such as La 3+ , Y 3+ , Lu 3+ and Sc 3+ ) with distinct cation field strengths in the oxyfluoride glasses.

A series of Ce3+ and Tb3+ ions codoped Ba3Y2B6O15 (BYBO) color tunable phosphors were successfully synthesized by high temperature solid state reaction. X-ray diffraction (XRD) patterns, crystal structure, excitation and emission spectra, CIE coordinates, thermal stability and internal quantum efficiency of these phosphors were systematically studied. An efficient cyan light was achieved in BYBO:0.03Ce3+,0.3Tb3+ phosphor, and the energy transfer mechanism from Ce3+ to Tb3+ ions was discussed in detail. Through coating BYBO:0.03Ce3+,0.3Tb3+ cyan-emitting phosphors with commercial CaAlSiN3:Eu2+ red phosphors on a 365 nm near-ultraviolet (NUV) LED chip, a white light-emitting diode (WLED) device with low correlated color temperature (4850 K), good color rendering index (92), and CIE chromaticity coordinates (0.3478, 0.3409) was fabricated. The results identified that BYBO:0.03Ce3+,0.3Tb3+ may be used as a cyan-emitting phosphor for NUV-pumped WLED application.

For glass ceramics, glass crystallization and doping activators into nanocrystalline phases are the key factors determining optical performance, including energy transfer (ET) process. Herein, we propose a strategy to verify ET behaviors based on glass crystallization, elaborately selecting phase-transformed NaYF4: Tb3+, Eu3+ nanocrystals embedded transparent glass ceramics as a typical example. The ET behaviors from Tb3+ to Eu3+ are clarified via photoluminescence spectra, time-resolved spectra and decay curves. Impressively, the corresponding ET process in cubic NaYF4 turns out to be more efficient than that in hexagonal, in spite of a disorder-to-order transformation from cubic to hexagonal. The reason for this abnormal ET efficiency is that dopants prefer to be partitioned into the cubic NaYF4 rather than the hexagonal one during glass crystallization. This work provides keen insights into the relationship between glass crystallization and ET behaviors, which can also feed back to helpfully guide the design and fabrication of glass ceramics with superior optical performance.

Glass ceramic has been regarded as an alternative to traditional bulk materials such as single crystal and transparent ceramic. The nucleation/growth behavior of glass ceramic via crystallization is an important topic but is seldom studied so far. In the present work, a series of La3+-based oxyfluoride aluminosilicate glasses are designed to understand their nanocrystallization processes upon heating. Impressively, controllable LaF3, α-NaLaF4 and β-NaLaF4 phase-competitive crystallization in glasses is achieved and structural/spectroscopic characterizations confirm the key role of Al/Si ratio to determine the release of Na+ ions from glass network to participate in crystallization and phase transformation. Furthermore, the developed glass ceramics are evidenced to be ideal hosts for lanthanide dopants (such as Eu3+ and Yb3+/Er3+), which can effectively incorporate into the precipitated fluoride crystal lattices by substituting La3+ ions. As a consequence, incoherent LED-excitable upconverting devices are constructed to demonstrate their promising application as emitting media in display.

Oxyfluoride glass-ceramics with RF3 or NaRF4 (R3+: rare earth elements) nanocrystals are considered as favorable hosts for luminescence applications. In this work, we utilized large-scale molecular dynamics (MD) simulations with effective partial charge potentials to study a series of oxyfluoride glasses that are of interest to the precipitation of RF3 or NaRF4 nanocrystals as previous experiment results suggested. The results show that phase separation exists in all glass compositions with fluoride-rich regions made up of R3+, Na+, and F– and oxide-rich regions consisting of aluminosilicate networks. These fluoride-enriched regions can serve as the precursor for RF3, cubic and hexagonal NaRF4, and NaF crystal precipitation. The results also confirm that the concentration of Na+ in the fluoride phase plays a key role in determining the crystal phases (RF3, NaRF4, or NaF) and crystal structure (cubic vs hexagonal NaRF4) to be precipitated. Consequently, this study shows that MD simulations with effective p...

Novel Mn4+-activated KLaMgWO6 red phosphors with different Mn4+ concentrations were successfully synthesized via a high-temperature solid-state reaction method. The phase formation, microstructure, photoluminescence properties, decay lifetimes and internal quantum efficiency were discussed to analyze the properties of the as-prepared phosphors. The samples belonged to monoclinic crystal system with enough WO6 octahedrons that provided suitable sites for Mn4+ ions. Upon the excitation of 348 nm, KLaMgWO6:Mn4+ phosphors gave bright far-red emission around 696 nm due to the 2Eg→4A2g transition of Mn4+ ions. The critical concentration of Mn4+ was 0.6 mol% and the concentration quenching mechanism belonged to electric multipolar interaction. Besides, the CIE chromaticity coordinates of the KLaMgWO6:0.6%Mn4+ phosphor were (0.7205, 0.2794) which located in deep red range, and its color purity reached up to 96.6%. The KLaMgWO6:0.6%Mn4+ sample also exhibited high internal quantum efficiency of 43%. All of the admirable optical properties indicate that the KLaMgWO6:Mn4+ phosphors can be applied to indoor plant growth illumination.

Currently, metal halide perovskite nanocrystals have been extensively explored due to their unique optoelectronic properties and wide application prospects. In the present work, a facile grinding method is developed to prepare whole-family APbX3 (A = MA, FA, and Cs; X = Cl, Br, and I) perovskite nanocrystals. This strategy alleviates the harsh synthesis conditions of precursor dissolution, atmosphere protection, and high temperature. Impressively, the as-prepared perovskite nanocrystals are evidenced to have halogen-rich surfaces and yield visible full-spectral emissions with maximal photoluminescence quantum yield up to 92% and excellent stability. Additionally, the grinding method can be extended to synthesize widely concerned Mn2+-doped CsPbCl3 nanocrystals with dual-modal emissions of both excitons and dopants. As a proof-of-concept experiment, the present perovskite nanocrystals are demonstrated to be applicable as blue/green/red color converters in UV-excitable white-light-emitting diodes.

Effective Mn2+ doping in a CsPbCl3 lattice utilizing manganese acetate and trimethylchlorosilane is achieved via a one-pot hot-injection synthesis method. This strongly contrasts to the previous case, where only the MnCl2 precursor was suitable for Mn2+ doping by considering the matching of bond dissociation energies between Mn-Cl and Pb-Cl. The Mn doping concentration and luminescence quantum yield are highly dependent on trimethylchlorosilane content. A new doping mechanism is proposed, where the incorporation of Mn2+ into CsPbCl3 is achieved via directly inserting [MnCl6]4- octahedra into the perovskite structure during the nucleation/growth processes instead of Mn-to-Pb cation exchange. Accordingly, increasing Cl- content in the reaction solution indeed promotes the doping of other divalent transition metal ions such as Ni2+, Cu2+ and Zn2+ in CsPbCl3 and improve the quantum yield of CsPbCl3 nanocrystals up to ∼20% compared to the undoped counterparts (∼1%).

β-NaYF4 nanocrystal embedded glass ceramics were fabricated by a melt-quenching method with subsequent heat-treatment. Structural characterizations and spectrographic techniques were performed to verify the successful precipitation of β-NaYF4 nanocrystals and partition of dopants. Upon excitation of 980 nm, bright green upconversion emission could be achieved in Yb3+, Er3+ codoped β-NaYF4 nanocrystal embedded glass ceramics. Furthermore, the temperature-dependent upconversion behaviour based on thermally coupled energy levels was also examined in the range of 300–773 K with the maximum relative sensitivity of 1.24% K−1 at 300 K. Accordingly, it has been proved to be a promising candidate for application in optical thermometry.

Efficient dual-modal luminescence is highly desired for applications in high security anti-counterfeiting. In the present work, Yb3+/Ln3+/Mn4+ (Ln = Er, Ho, and Tm) tri-doped Na3ZrF7 phosphors were fabricated via oil–water interface cation exchange using Yb3+/Ln3+:Na3ZrF7 as the exchanging hosts. The as-prepared products exhibited typical Mn4+ red down-shifting luminescence under UV light excitation and Er3+ red, Ho3+ yellow and Tm3+ near-infrared multi-color upconversion emissions under 980 nm laser excitation. The Mn4+ dopants in the Na3ZrF7 host experienced strong crystal-field strength Dq of 3.63 and showed superior thermal stability with up to 90% of the initial emission intensity retained at 448 K. Steady-state and time-resolved emission spectra verified that there was no detrimental energy transfer interaction between Mn4+ and Ln3+, enabling bright and eye-visible bi-functional emissions for the present products. As a consequence, the as-prepared phosphors were demonstrated to be applicable in anti-counterfeiting by a proof of concept experiment of fluorescent labeling for specially designed patterns.

Developing a novel non-rare-earth activated oxide red phosphor with admirable luminescent performance and low cost is still of great interest in the field of energy-saving warm white light-emitting diodes (w-LEDs) illumination. Here, Li3Mg2SbO6:Mn4+ (LMSO:Mn4+) red-emitting phosphor has been successfully prepared with cheap raw materials via a traditional solid-state method. Crystal structure, morphology, composition as well as optical properties are studied in detail. The prepared LMSO:Mn4+ phosphor exhibits a broad and deep red emission band in the range of 600–750 nm with the maximum centered at 666 nm, which is ascribed to the Mn4+:2Eg→4A2g transition in [SbO6] octahedral environment. Moreover, the nephelauxetic effect of Mn4+ in the LMSO matrix is evaluated by investigating the crystal field strength (Dq) and Racah parameters (B and C). Importantly, LMSO:0.01Mn4+ phosphor demonstrates good thermal stability and high quantum efficiency. By embedding LMSO:Mn4+ and Y3Al5O12:Ce3+ phosphors with various ratios in the TeO2-based glass host, a series of phosphors-in-glass(PiG) composites are achieved and demonstrate to remain the original optical properties of phosphors. Remarkably, by coupling PiG color converters with a blue LED chip, high-power w-LEDs devices with tunable optoelectronic parameters are constructed, with the correlated color temperature evolving from cool white (6783 K) to warm one (4014 K) and the color rendering index increasing from 72.2 to 88.7.

In situ nanocrystallization of homogeneously distributed Lu–Ln (Lu = La–Lu, Sc) solid-solution potassium lanthanide fluorides inside the same aluminosilicate glass matrix is reported. These precipitated nanocrystals exhibit Ln3+ radius dependent phase structures, i.e., cubic K(Lu/Ln)3F10 for large-radius Ln3+ ions and orthorhombic K(Lu/Ln)2F7 for small-radius Ln3+ ones. Particularly, a Lu–Yb system shows the ability to completely substitute between Lu and Yb in the K(Lu/Yb)2F7 nanocrystals, and Er (2 mol%):K(Lu0.5Yb0.5)2F7@glass yields the best upconversion quantum yield of 0.7%, which is far higher that the value of well-known Yb/Er (20/2 mol%):NaYF4@glass (0.13%). Taking Er/Tm:K(Lu0.5Yb0.5)2F7@glass as a color converter, a 980 nm laser-driven upconverted lighting device can be constructed to produce bright white-lighting with an optimal luminous efficiency of 0.53 lm W−1 and an energy efficiency of 1.31%. In addition, Er:KYb2F7@glass shows a significant photothermal effect owing to 100% Yb3+ host ions, leading to 980 nm laser-power-sensitive upconversion luminescence colors. As a proof-of-concept experiment, a specially designed Er:KYb2F7@glass-based flower pattern with tunable upconversion colors is adopted to demonstrate its practical application in high-end anti-counterfeiting.

Mn-Doped CsPb(Cl/Br)3 quantum dots possess multi-functional optical, electronic and magnetic characteristics. However, they usually suffer from decomposition in air, and Mn2+ dopants will be gradually expelled from the perovskite host due to a radius mismatch between Pb2+ and Mn2+. To solve these crucial issues, the synthesis of glass stabilized Mn-doped quantum dots via an appropriate glass composition design and in situ glass crystallization is reported. Mn2+ dopants act as nucleating agents to promote the nucleation/growth of CsPb(Cl/Br)3 from B-P-Zn-Cs-Pb based oxyhalide glass and partition into the perovskite host to produce dual-color luminescence via efficient exciton-to-dopant energy transfer. Benefitting from the effective protection of robust glass, Mn-doped CsPb(Cl/Br)3 quantum dots exhibit superior water resistance and thermal stability. Particularly, almost 100% luminescence is retained after immersing the composite in water for 30 days. Interestingly, rapid thermal quenching for exciton recombination relative to Mn2+ d-d transition at cryogenic temperatures enables its promising applications as a ratiometric temperature sensing medium.

Laser lighting, generally consisting of a blue laser and downconversion phosphors, is considered to be the next promising form of illumination to replace traditional LED lighting. However, irradiation with a high-powered blue laser will inevitably cause significant thermal attack, which places a high demand on phosphor converters as well as on device architecture. In this work, a proof-of-concept prototype of near-infrared laser-driven upconversion solid-state-lighting is proposed. Robust lanthanide doped α/β-NaYF4 embedded glass ceramics are developed as upconverted color converters and a routine 980 nm laser is used as the pumping source for its relatively low thermal effect and perfect resonance with Yb3+ sensitizers. Stable and bright upconversion white light is indeed produced by coupling a Yb/Tm/Er doped α-NaYF4 glass ceramic with a 980 nm laser, but the luminous efficiency and energy efficiency are only 0.3 lm W−1 and 0.12%, respectively, owing to low Er doping concentration. As an alternative, a stacking structure of Yb/Tm doped and Yb/Er doped glass ceramics is designed as a color converter to improve the luminous efficiency up to 1.0 lm W−1 and energy efficiency up to 0.5% under a laser power density of 275 W cm−2. It is believed that this research will provide a new idea for laser lighting and open up the application field of glass ceramics.