最新刊期
卷 44 ， 期 8 ， 2023
- 摘要：Hexagonal phase NaYF4∶20%Yb，2%Er@NaYF4@NaYbF4∶0.5%Tm@NaYF4 lanthanide-doped nano⁃particles with the core@multishell structure were synthesized by solvothermal method. The upconversion luminescence （UCL） properties of the materials at temperature from 10 K to 295 K were studied under 980 nm excitation. Green and red UCL from Er3+ and blue UCL from Tm3+ were observed in the visible light range. The luminescence intensity of green UCL first increased and then decreased， while the luminescence intensity of blue light showed a thermal attenuation trend with the temperature increase. The method of temperature-dependent luminescence intensity ratio （LIR） can be used in accurate temperature measurement， and the relative sensitivity is up to 3.2%·K-1. With various thicknesses of the outer luminescent shell， the different tendencies of LIR can be realized， which can be applied to cryogenic field anticounterfeiting.关键词：rare-earth nanoparticles;luminescence intensity ratio（LIR） thermometry;upconversion luminescence cryogenic field;anticounterfeiting
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发布时间：2023-09-06
Cover Story
- 摘要：Lead halide perovskite luminescent materials have attracted much attention due to their unique optoelectronic advantages such as high fluorescence quantum yield， narrow emission spectrum， and adjustable emission wavelength. However， the toxicity of metal lead and the stability of perovskite are the problems that need to be solved in the practical application in the field of flat-panel display and solid-state lighting in the future. Therefore， it is an imperative trend to explore more green and environment-friendly lead-free metal halide perovskite luminescent materials with the same optoelectronic properties as lead-based counterparts. In recent years， significant progress has been made in the research of lead-free metal halide perovskite variant （LFMHPV） luminescent materials. In this review， the crystal structure， preparation methods and luminescent mechanism of LFMHPVs are summarized. The factors affecting the photoelectric properties of these materials are discussed， and their applications in the field of photoluminescence and electroluminescence devices are categorized. Finally， how to further improve the performance of LFMHPV luminescent materials is summarized and prospected， which is conceived to provide useful guidelines for further design and application of novel metal halides with high performance.关键词：metal halide;perovskite variant;luminescent materials;photoluminescence devices;electroluminescence devices
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发布时间：2023-09-06
Invited Review
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Broadband Near Infrared Emission and Energy Transfer of Ca2TbHf2Al3O12∶Ce3+,Cr3+ Garnet Phosphor 增强出版
摘要：Broadband near infrared （NIR） phosphor-converted light-emitting diodes （pc-LEDs） have been widely concerned due to their valuable application in spectral analysis， biological imaging， night vision lighting and other fields. In this work， the novel NIR-emitting Ca2TbHf2Al3O12∶Ce3+，xCr3+ （CTHAO∶Ce3+，xCr3+） phosphors were prepared by high temperature solid state method. CTHAO∶Ce3+，xCr3+ were confirmed to be pure phase with garnet structure by powder XRD and Rietveld refinement technology. Tb3+， as matrix component， can sensitize Cr3+ ions. Co-doping Ce3+ leads to multiple energy transfer processes， and the energy transfer fact of Ce3+→Tb3+， Ce3+→Cr3+， Tb3+→Cr3+ was confirmed by the spectra and fluorescence lifetime characterization. The energy transfer mechanism from Tb3+ to Cr3+ is dominated by dipole-quadrupole interaction， and the energy transfer efficiency can reach 79.5%. The NIR intensity of CTHAO∶Ce3+，0.02Cr3+ can maintain 36% compared with its initial intensity and the calculated activation energy is 0.30 eV. Combining CTHAO∶Ce3+，0.02Cr3+ with a 410 nm chip， the NIR output power can reach 7.5 mW and the NIR photoelectric conversion efficiency is 1.2% when the driving current is 200 mA. In this work， the enhancement of Cr3+ luminescence through multiple energy transfer processes has certain guiding significance for the design and development of Cr3+ excited efficient near infrared luminescence materials.关键词：energy transfer;Cr3+;phosphor-converted light-emitting diode（pc-LED）;broadband near infrared emission- 335
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发布时间：2023-09-06 - 摘要：It is a feasible way to adjust emission behaviors by molecular conformation and intermolecular interactions. Herein， two multifunctional materials， 4，4'-（benzo［c］［1，2，5］thiadiazole-4，7-diyl）bis（N，N-diphenylaniline） and 4-（7-（9，9-dimethylacridin-10（9H）-yl）benzo［c］［1，2，5］thiadiazol-4-yl）-N，N-diphenylaniline， namely TBT and DBT， with donor-acceptor-donor （D-A-D） and D-A-D′ structures composed of 2，1，3-benzothiadiazole （BT） acceptor and the different donors of triphenylamine （TPA） and 9，9-dimethyl-9，10-dihydroacridine （DMAC） were synthesized. These materials exhibit not only polymorphism-dependent emission but also multicolor luminescence switch in response to the external stimulus. The high-contrast crystal-dependent emission behaviors of TBT （TBT⁃O： λPL=593 nm and TBT⁃R： λPL=616 nm） and DBT（DBT⁃Y： λPL=570 nm， DBT⁃O： λPL=605 nm and DBT⁃R： λPL=642 nm） were observed. TBT with double TPA groups exhibits four reversible color switches， while DBT with TPA and DMAC groups shows irreversible bicolor change.关键词：Benzothiadiazole;Mechanochromic responses;Multicolor luminescence
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发布时间：2023-09-06 - 摘要：Efficient optical modulation enables a prominent improvement of optical conversion efficiency and regulation of optical response rate， which shows great potential in the field of optoelectronics. However， the weak interaction between photons poses a strong obstacle for manipulating photon-photon interactivity. Here， upon simultaneous excitation of 850 nm and 1 550 nm， a fast-slow optical modulation of green up-conversion luminescence in oxyfluoride glass ceramics containing Er3+∶NaYF4 nanocrystals can be achieved. Compared with the sum of the luminescence intensity with two single-wavelength excitations， the green up-conversion luminescence intensity excited by simultaneous two-wavelength presents a significant increase by an order of magnitude. It is worth noting that the fast-slow response rate of green up-conversion luminescence relies on the pump strategy of two-wavelength excitation， showing as high as four times of the fast-slow response difference. The fast-slow optical modulation of green up-conversion luminescence under two-wavelength excitation may find potential applications in emerging all-optical switching.关键词：glass-ceramics;NaYF4 nanocrystals;two-wavelength excitation;up-conversion fluorescence
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发布时间：2023-09-06 - 摘要：A naphthalimide compound called oCz-NI was designed and synthesized. Theoretical calculations revealed a distorted structure with a small spatial distance between the electron donor and electron acceptor， which facilitated the space charge transfer. Photoluminescence spectroscopy in different solvents showed the presence of intramolecular charge transfer in oCz-NI. The variable temperature spectroscopy tests indicated an increase in the fluorescence intensity of the powder with rising temperature， suggesting the presence of thermally activated delayed fluorescence（TADF） properties in oCz-NI. These results highlight the feasibility of designing TADF materials using a space charge transfer strategy. The thermogravimetric analyses and differential scanning calorimetry measurements suggested good thermal stability of oCz-NI， while the thermal decomposition at 5% weight loss temperature was 350 ℃ and the glass transition temperature was 121 ℃. Furthermore，When oCz-NI was adopted to fabricate organic light-emitting diode， the electroluminescence peak wavelength was 496 nm， the maximum luminance was obtained to be 1 405 cd/m2 and the maximum external quantum efficiency was achieved to be 4.11%.关键词：naphthalene imide;space charge transfer;thermally activated delayed fluorescence;organic light-emitting diode;intramolecular charge transfer
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发布时间：2023-09-06 - 摘要：WO3 is an ideal inorganic electrochromic material. Its electrochromic mechanism is reversible redox reaction under the driving of voltage， accompanied by the insertion and extraction of counterions in the material. In this paper， we investigated the electrochromic properties of amorphous WO3 in three aqueous electrolyte solutions of Li， Zn and Al. WO3 achieves the best electrochromic performances when Al3+ was used as insertion ions， including fast response speed （2.8 s for coloring and 1.1 s for decolorization）， large optical contrast （83.4% at 700 nm）， good cycling stability （2.8% decay for 1 000 successive cycles）， high coloration efficiency （74.7 cm2·C-1）， and its comprehensive performance is at high level among the reported WO3 electrochromic devices. Mechanistic studies have revealed that the enhanced performance in Al3+ electrolytes is due to the fast ion transport kinetics. These results will provide a simple and effective guidance for the construction of high-performance electrochromic devices and the optimization of electrolytes.关键词：electrochromic;WO3;aqueous electrolytes;stability;amorphous
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发布时间：2023-09-06 -
Optical Properties of CsPb
x Sn1-x Br3/a-ZrP Perovskite Quantum Dots for White Light-emitting Diodes 增强出版摘要：Nowadays， perovskite （CsPbX3， X=Cl， Br， I） quantum dots （PQDs） have been widely used in optical properties due to their high photoluminescence quantum yield （PLQY）， adjustable band gap， high color purity， and low cost. However， due to its inherent instability， such as oxygen， heat， and moisture. It is still a problem to hinder the applications of lead halide perovskite. In this paper， we synthesize CsPbxSn1-xBr3/a-ZrP PQDs at room temperature. Compared with the original CsPbBr3 PQDs， CsPbxSn1-xBr3/a-ZrP PQDs have better optical performance and stability. Due to the inherent characteristics of a-ZrP nanosheets for high Pb2+ adsorptivity and good ability to exchange ions with Cs+， it promoted adsorption and anchoring of perovskite quantum dots on the surface of a-ZrP. Therefore， the synthesized CsPbxSn1-xBr3/a-ZrP PQDs have higher exciton binding energy and stronger environmental stability. The PQDs provide a feasible method for producing stable and efficient perovskite quantum dots， and show that CsPbx⁃Sn1-xBr3/a-ZrP PQDs are efficient down-conversion fluorescent materials for the preparation of high-efficiency LEDs.关键词：perovskite;quantum dots;adsorption;Sn2+ doped;photoluminescence enhanced;white light-emitting diodes- 268
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发布时间：2023-09-06
Synthesis and Properties of Materials
- 摘要：In recent years， metal halide perovskite materials have shown a bright application prospect due to their high photoluminescence quantum efficiency， tunable luminescence wavelength， high color purity， low cost and solution-processed fabrication at room temperature. At present， the external quantum efficiency of lead-based perovskite light emitting diode（PeLED） has exceeded 28%. However， the toxicity of heavy metal lead seriously hinders its large-scale production and commercial development. Therefore， the development of low toxicity lead-free PeLED has become an urgent problem in this field. In order to solve this problem， researchers try some solutions to replace Pb， such as Sn， Bi， Sb， Cu， etc. However， the performance of lead-free perovskite is far from that of Pb based perovskite， so people have adopted doping， improved preparation methods and device structures to improve the performance. This paper first introduces the preparation methods of lead-free perovskite， then summarizes the research progress， advantages and disadvantages， existing problems and improvement direction of lead-free PeLEDs， and finally makes prospects for the future development.关键词：light emitting diode;perovskite;lead-free;performance
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发布时间：2023-09-06 - 摘要：Because metal oxides have good thermal stability and low sensitivity to water/oxygen， they are used as the most important charge transfer materials in quantum dot light emitting diodes （QLED） devices. However， the charge transfer ability of different metal oxides is different， and the interface energy level matching problem in different device structures will cause the charge imbalance and even lead to exciton quenching. Therefore， in order to obtain good device performance， it is necessary to modify and optimize the interface while ensuring the stability of the material. In this paper， metal oxides as charge transport layer， charge injection layer and charge blocking layer are described respectively， and the development of metal oxides in QLED applications in recent years is summarized by mixing other materials and constructing reasonable device structures.关键词：metallic oxide;charge transfer layer;charge injection layer;charge barrier layer;composite interface function layer
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发布时间：2023-09-06 - 摘要：Due to its excellent photoelectric characteristics and solution processability， perovskite has made unprecedented radical progress in the fields of display and lighting. In this paper， in order to reduce the content of Pb ion， we proposed to introduce germanium ions （Ge2+） into the perovskite lattice and realize partial substitution of Pb2+， then we explored ways to improve the performance. Because Ge alloying can make perovskite tolerance factor closer to 1， it is expected that device stability can be improved. The experimental results showed that the photoluminescence stability of Ge-alloyed perovskite films is greatly improved in a certain time under water and oxygen environment， and the PeLED device performance and operation stability are improved， which is mainly attributed to GeO2 formed on the surface of alloyed perovskite after the water and oxygen treatment. As a result， a green-light Ge-alloyed perovskite light-emitting diode was obtained with a maximum external quantum efficiency （EQEmax） of 11.8%， maximum luminance of 8×103 cd/m2. What's more， the device's lifetime was extended three times by germanium alloying， and the T50 of the device was improved from ~2 h to ~6 h with an initial brightness of 100 cd/m2， which is the longest luminous life of Ge-alloyed PeLEDs.关键词：Ge-alloyed perovskite;Water and oxygen treatment;light-emitting diode;Luminous stability
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发布时间：2023-09-06 - 摘要：The 540 nm frequency-doubled green laser was first realized on a novel Nd∶Gd0.1Y0.9AlO3（Nd∶GYAP） crystal. The fundamental-frequency wavelength that was generated by Nd∶GYAP crystal centered at 1 079.4 nm， and the frequency-doubled green laser was centered at 539.4 nm with a threshold of 46 mW and a maximum output power of 65 mW. An LBO was selected as the frequency-doubling crystal. The ~540 nm green laser can avoid the absorption peak of Nd3+ at near 530 nm. The green laser with longer wavelengths at approximately 540 nm can make the output more efficient， and expand the application of the green laser.关键词：LBO;Nd∶GYAP;Frequency doubling;540 nm laser;Green laser
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发布时间：2023-09-06 - 摘要：Based on the synthesis of Cs3Bi2I9 precursor solution by using solution method， Cs3Bi2I9/BiI3 thin films were obtained by adding BiI3 to modify Cs3Bi2I9 solution， and the Cs3Bi2I9/BiI3 photodetectors based on the device types of photoelectrochemical detectors with self-powered properties were also constructed. It is found that the added BiI3 exists in the form of the second phase， forming a two-phase mixed structure. Under illumination of ultraviolet（365 nm） monochromatic light， Cs3Bi2I9/BiI3 photodetectors show on-off ratio of 3 198， corresponding to a response of 2.85×10-3 A/W and a detectivity of 3.77×1010 Jones. While under illumination of green light（530 nm）， the device also exhibits on-off ratio of 1 172， a response of 6.9×10-4 A/W and a detectivity of 1.76×1010 Jones. Compared with simple Cs3Bi2I9 photodetectors， the detection performance of Cs3Bi2I9/BiI3 photodetectors has been greatly improved， which is attributed to the passivation of BiI3 on non-radiation defects. It is the first time to apply Cs3Bi2I9 in the photoelectrochemical structure detector. The modification of BiI3 successfully improves the device performance， which provides a new idea for improving the performance of low-toxic bismuth-based perovskite photodetection application.关键词：Cs3Bi2I9;Photoelectrochemical Detectors;Self-powered Detection;BiI3;Second Phase
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发布时间：2023-09-06 - 摘要：A tunable single-longitudinal-mode thulium-doped fiber laser based on a uniform fiber Bragg grating（UFBG）and a double-ring compound sub-cavity filter is proposed and verified. A UFBG with a 0.18-nm reflection peak as wavelength-switchable element and a double-ring compound sub-cavity filter as the mode-selection mechanism are combined to realize the single⁃longithudinal⁃mode（SLM） laser. The wavelength of the laser was 2 048.69 nm and the optical signal-to-noise ratio was 71.82 dB. The maximum wavelength and power fluctuations within 60 min are found to be 0.03 nm and 0.76 dB， respectively. Moreover， the relative intensity noise is below -127.81 dB/Hz above 0.5 MHz. The laser linewidth at 0.001 s was measured as 7.719 6 kHz using an imbalanced Michelson interferometer composed of a 3 × 3 coupler. The lasing achieves a wide tunable range of 5.1 nm， which is obtained by tuning the micro-displacement platform to transform the strain on the UFBG.关键词：fiber laser;thulium-doped fiber;single-longitudinal-mode;double-ring compound sub-cavity filter
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发布时间：2023-09-06 - 摘要：Flexible reflective electrochromic devices have broad application prospects in e-paper displays， camouflage， and intelligent color-changing surfaces， but there are still problems such as poor flexibility， low optical contrast， and poor stability. Indium-free reflective electrochromic electrodes with Cr/Ag/WO3 （CAW） structure have been prepared by electron beam evaporation on glass and flexible PET substrates. CAW films have high reflectance and low surface resistance. The average visible light reflectance is up to 89.2%， and the surface resistance is only 1.2 Ω/□. In terms of electrochromic properties， CAW films show fast colored and bleached response times of 9.3 s and 2.0 s， high optical contrast of up to 83.0% （564 nm）， wide range of reflective color modulation （>40 nm）， and excellent electrochemical cycling stability （>4 500 cycles）. In addition， CAW films have good substrate compatibility. We prepared flexible CAW films and assembled patterned flexible electrochromic devices. The electrical properties of the flexible film remain almost unchanged after 2 000 consecutive bends and the optical contrast reaches 83.2% at 574 nm. The devices realize rich reflected color dynamic regulation under different voltages. These results will provide simple and effective guidance for the construction of high-performance flexible reflective electrochromic devices， and have certain application potential in the field of new display technology.关键词：electrochromic;WO3;Indium-free;flexibility;reflection
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发布时间：2023-09-06
Device Fabrication and Physics
- 摘要：SiO2 usually exists in three-dimensional crystal or amorphous structure， which limits its application in new technologies such as new integrated circuits， so the research on two-dimensional SiO2 has attracted more and more attention. In this paper， a new two-dimensional SiO2 configuration is constructed directly by removing Ca and Al atoms from the three-dimensional layered CaAl2Si2O8 structure. Using the first principles calculation based on density functional theory， the structure optimization results in the new 2D SiO2 with P⁃62m symmetry and group number 189. Through calculating binding energy， elastic coefficient， molecular dynamics simulation and phonon spectrum， it is found that the new 2D SiO2 has high mechanical， thermodynamic and dynamic stability. Further calculations of electronic and optical properties show that 2D SiO2 is an insulator with band gap of 6.08 eV， and has good optical transmittance and optical conductivity. In addition， by studying the effect of in-plane biaxial strain on the electronic and optical properties of 2D SiO2， it is shown that the band gap and dielectric function of 2D SiO2 are slightly more affected by the in-plane tensile strain than by the compression strain， but the strain impact on the overall optical properties of 2D SiO2 is modest， which ensures the stability of the electronic and optical properties in practical applications.关键词：two-dimensional SiO2;electronic properties;optical properties;first-principles calculations
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发布时间：2023-09-06
Theoretical Calculation and Spectral Analysis
- 摘要：Porphyrin-metal-organic frameworks （MOFs） materials are a new class of porous materials composed of metal nodes and porphyrin organic ligands. The porphyrin ligands on the MOFs can exert photodynamic therapy （PDT） under light excitation. This kind of PDT material with porous structure can play the functions of drug loading and multifunctional modification in the treatment of diseases. Some MOFs with unique metal sites also have the function of nanozymes. In recent years， this kind of porphyrin-MOFs has become an important research direction in the field of PDT. At present， such materials need to solve problems such as oxygen concentration and energy transfer efficiency before being promoted to the clinic. Researchers have also given many solutions， and adopt different methods to enhance PDT according to different environments faced in the actual application process， including increasing oxygen concentration， improving the energy transfer process， consumption of functional molecules， generation of signal molecules and synergistic strategies. This paper reviews the representative work in recent years， including porphyrin-MOFs materials and the mechanism of PDT generation， the application and latest progress of PDT of porphyrin-MOFs materials. Finally， the future development trend of PDT for porphyrin-MOFs materials in the field of biomedicine has prospected.关键词：porphyrins;metal-organic frameworks;photodynamic therapy
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发布时间：2023-09-06
Luminescence Applications and Interdisciplinary Fields
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