本文研究了CaS<sub>1-x</sub>Se<sub>x</sub>∶Eu（0【x【0.5）荧光粉层的薄膜特性,薄膜是用 CaS∶Eu 和 Se 源并利用共蒸发技术制备的。使用这种荧光粉层的红色电致发光器件在频率为lkHz、脉宽为30μs的双极...本文研究了CaS<sub>1-x</sub>Se<sub>x</sub>∶Eu（0【x【0.5）荧光粉层的薄膜特性,薄膜是用 CaS∶Eu 和 Se 源并利用共蒸发技术制备的。使用这种荧光粉层的红色电致发光器件在频率为lkHz、脉宽为30μs的双极性脉冲激发下,亮度高达650cd/m<sup>2</sup>,最大效率为0.4lm/W。展开更多
提出了5类实现Si基激光器的增益介质材料,即具有强三维量子限制效应的纳米晶Si(nc-Si)薄膜,掺稀土发光中心Er的Si基纳米材料,具有预期人工改性的高纯体单晶Si,基于子带跃迁的SiGe/Si量子级联结构,以及具有受激Raman散射特性的SOI(silico...提出了5类实现Si基激光器的增益介质材料,即具有强三维量子限制效应的纳米晶Si(nc-Si)薄膜,掺稀土发光中心Er的Si基纳米材料,具有预期人工改性的高纯体单晶Si,基于子带跃迁的SiGe/Si量子级联结构,以及具有受激Raman散射特性的SOI(silicon on insulator)光波导结构．评述了这些材料在近3～5年中在高效率光致发光(PL)、电致发光(EL)、光增益和受激光发射特性方面所取得的重要进展,并简要讨论了今后发展中存在的一些问题．展开更多
Glass substrates which realize high out-coupling efficiency OLEDs （organic light emitting diodes） were developed. A scattering layer whose matrix was made of high refractive index glass was formed on a glass substra...Glass substrates which realize high out-coupling efficiency OLEDs （organic light emitting diodes） were developed. A scattering layer whose matrix was made of high refractive index glass was formed on a glass substrate, and pores in the glass matrix work as scattering centers. The out-coupling efficiency of an OLED using this substrate is 1.8 times higher compared with an OLED using an untreated glass substrate. Furthermore angular dependency of the color and color variation between panels can be successfully suppressed.展开更多
For healthy lighting,daily lighting that considers both visible light and near-infrared(NIR)light is necessary.However,at~900 nm,the extensively used solar-like phosphor-converted light-emitting diodes(pc-LEDs)are lim...For healthy lighting,daily lighting that considers both visible light and near-infrared(NIR)light is necessary.However,at~900 nm,the extensively used solar-like phosphor-converted light-emitting diodes(pc-LEDs)are limited by a lack of high-performance NIR luminescent materials.We report a broadband NIR phosphor Sr_(2)ScSbO_(6):Cr^(3+) with a double perovskite-type structure,thus simultaneously demonstrating high luminescence efficiency and good thermal stability.Under 550-nm excitation,Sr_(2)ScSbO_(6):Cr^(3+) demonstrates broadband NIR emission centered at~890 nm with luminescence internal/external efficiencies of 82.0%/35.7%,respectively.Furthermore,the luminescence integrated intensity at 430 K remains at~66.4% of the initial intensity.We successfully fabricated pc-LED devices using a 465-nm-sized blue chip and other commercial phosphors,presenting a relatively complete solar-like spectrum from blue to NIR light and is expected to be used in solar-like lighting.展开更多
Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art perfo...Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art performance,the high photoluminescence quantum yield(PLQY)of the active emission layer,the balanced charge injection,and the optimized optical extraction should be considered simultaneously.Multiple chemical passivation strategies have been provided as controllable and efficient methods to improve the PLQY of the perovskite layer.However,high luminance under large injection current and high external quantum efficiency(EQE)can hardly be achieved due to Auger recombination at high carrier density.Here,we decreased the electron injection barrier by tuning the Fermi-level of the perovskite,leading to a reduced turn on voltage.Through molecular doping of the hole injection material,a more balanced hole injection was achieved.At last,a device with modified charge injection realizes high luminance and quantum efficiency simultaneously.The best device exhibits luminance of 55,000 cd m^-2 EQE of 8.02%at the working voltage of 2.65 V,current density of 115 mA cm^-2,and shows EQE T50 stability around 160 min at 100 mA cm^-2 injection current density.展开更多
Binding of fluorescent molecules to the porous matrix through noncovalent interactions will synergistically expand their application spectrum. In this regard, we report an integrative self-assembly of molecule 1 with ...Binding of fluorescent molecules to the porous matrix through noncovalent interactions will synergistically expand their application spectrum. In this regard, we report an integrative self-assembly of molecule 1 with benzothiadizole and 9,9-dihexyl fluorene units, and covalent organic frameworks(COFs) via an emulsion-modulated polymerization process, within which molecules of 1 are able to interact with the scaffolds of COFs through CH-π interactions. Thus the π-πinteractions between the fluorescent molecules are largely suppressed, giving rise to their remarkable monomer-like optical properties. Of particular interest is that, given by the specific interaction between COFs and a nerve agent simulant diethyl chlorophosphite(DCP), these assembled composites show the ability of ultrasensitive detection of DCP with a detection limit of ~40 ppb. Moreover, the present integrative assembly strategy can be extended to encapsulate multiple fluorescent molecules, enabling the assemblies with white light emission. Our results highlight opportunities for the development of highly emissive porous materials by molecular selfassembly of fluorophores and molecular units of COFs.展开更多
文摘本文研究了CaS<sub>1-x</sub>Se<sub>x</sub>∶Eu（0【x【0.5）荧光粉层的薄膜特性,薄膜是用 CaS∶Eu 和 Se 源并利用共蒸发技术制备的。使用这种荧光粉层的红色电致发光器件在频率为lkHz、脉宽为30μs的双极性脉冲激发下,亮度高达650cd/m<sup>2</sup>,最大效率为0.4lm/W。
文摘提出了5类实现Si基激光器的增益介质材料,即具有强三维量子限制效应的纳米晶Si(nc-Si)薄膜,掺稀土发光中心Er的Si基纳米材料,具有预期人工改性的高纯体单晶Si,基于子带跃迁的SiGe/Si量子级联结构,以及具有受激Raman散射特性的SOI(silicon on insulator)光波导结构．评述了这些材料在近3～5年中在高效率光致发光(PL)、电致发光(EL)、光增益和受激光发射特性方面所取得的重要进展,并简要讨论了今后发展中存在的一些问题．
文摘Glass substrates which realize high out-coupling efficiency OLEDs （organic light emitting diodes） were developed. A scattering layer whose matrix was made of high refractive index glass was formed on a glass substrate, and pores in the glass matrix work as scattering centers. The out-coupling efficiency of an OLED using this substrate is 1.8 times higher compared with an OLED using an untreated glass substrate. Furthermore angular dependency of the color and color variation between panels can be successfully suppressed.
基金supported by the National Natural Science Foundation of China(51972020 and 51832005)。
文摘For healthy lighting,daily lighting that considers both visible light and near-infrared(NIR)light is necessary.However,at~900 nm,the extensively used solar-like phosphor-converted light-emitting diodes(pc-LEDs)are limited by a lack of high-performance NIR luminescent materials.We report a broadband NIR phosphor Sr_(2)ScSbO_(6):Cr^(3+) with a double perovskite-type structure,thus simultaneously demonstrating high luminescence efficiency and good thermal stability.Under 550-nm excitation,Sr_(2)ScSbO_(6):Cr^(3+) demonstrates broadband NIR emission centered at~890 nm with luminescence internal/external efficiencies of 82.0%/35.7%,respectively.Furthermore,the luminescence integrated intensity at 430 K remains at~66.4% of the initial intensity.We successfully fabricated pc-LED devices using a 465-nm-sized blue chip and other commercial phosphors,presenting a relatively complete solar-like spectrum from blue to NIR light and is expected to be used in solar-like lighting.
基金in part supported by Research Grants Council of Hong Kong,particularly,via Grant Nos.Ao E/P-03/08,T23-407/13-N,Ao E/P-02/12,14207515,14204616CUHK Group Research Scheme,and ITS/088/17 by Innovation and Technology Commission,Hong Kong SAR Governmentthe National Natural Science Foundation of China for the support,particularly,via Grant No.61229401。
文摘Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art performance,the high photoluminescence quantum yield(PLQY)of the active emission layer,the balanced charge injection,and the optimized optical extraction should be considered simultaneously.Multiple chemical passivation strategies have been provided as controllable and efficient methods to improve the PLQY of the perovskite layer.However,high luminance under large injection current and high external quantum efficiency(EQE)can hardly be achieved due to Auger recombination at high carrier density.Here,we decreased the electron injection barrier by tuning the Fermi-level of the perovskite,leading to a reduced turn on voltage.Through molecular doping of the hole injection material,a more balanced hole injection was achieved.At last,a device with modified charge injection realizes high luminance and quantum efficiency simultaneously.The best device exhibits luminance of 55,000 cd m^-2 EQE of 8.02%at the working voltage of 2.65 V,current density of 115 mA cm^-2,and shows EQE T50 stability around 160 min at 100 mA cm^-2 injection current density.
基金supported by the National Natural Science Foundation of China (21703120,21972076,51903140 and 21925604)China Postdoctoral Science Foundation (2019M662324)Taishan Scholars Program of Shandong Province (tsqn201812011)。
文摘Binding of fluorescent molecules to the porous matrix through noncovalent interactions will synergistically expand their application spectrum. In this regard, we report an integrative self-assembly of molecule 1 with benzothiadizole and 9,9-dihexyl fluorene units, and covalent organic frameworks(COFs) via an emulsion-modulated polymerization process, within which molecules of 1 are able to interact with the scaffolds of COFs through CH-π interactions. Thus the π-πinteractions between the fluorescent molecules are largely suppressed, giving rise to their remarkable monomer-like optical properties. Of particular interest is that, given by the specific interaction between COFs and a nerve agent simulant diethyl chlorophosphite(DCP), these assembled composites show the ability of ultrasensitive detection of DCP with a detection limit of ~40 ppb. Moreover, the present integrative assembly strategy can be extended to encapsulate multiple fluorescent molecules, enabling the assemblies with white light emission. Our results highlight opportunities for the development of highly emissive porous materials by molecular selfassembly of fluorophores and molecular units of COFs.
