CERAMICS INTERNATIONAL
·
2022
·Vol. 49
·期 7
·10273-10279
·
IF 5.532
Daiyuan Liu,Ting Wang,Yichun Liu,Chao Wang,Zhichao Liu,Xiaodie Zhu,Ya Liu,Jian Zhang,Zhaowei Teng,Yang Zhong,Yakovlev Alexey Nikolaevich,Xuhui Xu
The photoluminescence behavior of inorganic phosphors is generally influenced by thermal stability, which determines the luminescence efficiency of the corresponding devices. Here, a series of Eu 2+ , Mn 2+ co-doped LiAl 5 O 8 blue-green-emitting phosphors with thermal robust are successfully fabricated. The concentration-dependent emission spectra and the decay curves of the as-obtained LiAl 5 O 8 : Eu 2+ , Mn 2+ samples manifest the occurrence of the energy transfer from Eu 2+ to Mn 2+ ions via dipole-dipole interaction, and the corresponding emitted colors are gradually modulated from blue to green under the excitation of 310 nm. Moreover, the zero-thermal-quenching luminescence is observed when the operation temperature is up to 423 K, which is attributed to the energy release from the trapping centers to emitting centers (Eu 2+ and Mn 2+ ) at high temperature. Furthermore, a warm white light-emitting diodes (WLEDs) device with correlated color temperature of 5061 K, a color rendering index of 80.6 and long-term stability is fabricated by combining UV LED chip (λ ex = 310 nm), as-obtained LiAl 5 O 8 : Eu 2+ , Mn 2+ phosphor, commercially available red phosphor and green phosphor. These results prove the potential application of the as-obtained LiAl 5 O 8 : Eu 2+ , Mn 2+ phosphor for UV-pumped WLEDs devices.
研究领域:
材料科学
·
发光材料
·
固态化学
·
光电子学
·
无机化学
·
器件物理
·
纳米材料
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2023
·Vol. 53
·期 3
·996-1003
·
IF 4
Qiang Zhang,Xin Ding,Bin Liu,Yuhua Wang
The development of novel phosphors with excellent luminescence properties for white light-emitting diodes (WLEDs) is always a formidable task. Compared with the traditional laborious and aimless “trial and error” experiments, a mineral-inspired prototype strategy can provide an efficient and accurate method. Herein, for the first time, a novel yellow-emitting phosphor NaBaY2(PO4)3:Eu2+ was discovered using the mineral-inspired prototype strategy and cation substitution method. The phosphor was prepared via the high-temperature solid-state reaction method, and its crystal structure, luminescence properties and potential application for WLEDs were systematically investigated. The NaBaY2(PO4)3 phase was derived from the K2Mg2(SO4)3-type mineral structure and a photoluminescence study revealed that the phosphor can emit bright yellow light with a maximum at 545 nm upon excitation at 351 nm. A WLED lamp was fabricated by the use of a blend of commercial blue-emitting BaMgAl10O17:Eu2+, yellow-emitting NaBaY2(PO4)3:Eu2+ and red-emitting (Ca, Sr)AlSiN3:Eu2+ phosphors with a 380 nm LED chip. The CIE, CCT, Ra and efficiency of the as-fabricated LEDs were measured to be equal to (0.366, 0.365), 4327 K, 91.2 and 40.8 lm W−1, respectively. These results suggest that NaBaY2(PO4)3:Eu2+ could be a promising candidate for n-UV WLEDs.
研究领域:
材料科学
·
无机化学
·
光电子学
·
半导体照明
·
发光材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Ning Mao,Shengqiang Liu,Zhen Song,Yi Yu,Quanlin Liu
Near-infrared phosphor (NIR) integrated light-emitting diode (LED) has ideal application prospects in the fields of food inspection and medical imaging. Herein, we have synthesized a garnet-type Ca 3 Y 2 Ge 3 O 12 :Cr 3+ NIR phosphor using solid state reaction method. Broadband NIR emission ranging from 700 to 1100 nm with a peak located at 800 nm indicates a weak crystal field strength for Cr 3+ , which occupies the six-coordinated Y 3+ site. Moreover, the phosphor has satisfactory luminous intensity showing 81%/10% internal/external quantum efficiency and excellent luminescence thermal stability. Our work provides an excellent NIR phosphor choice for NIR LED devices.
研究领域:
材料科学
·
光学工程
·
生物医学工程
·
分子影像
·
光电子学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 24
·8414-8424
·
IF 4
Tao Tan,Ran Pang,Shangwei Wang,Haiyan Wu,Jiutian Wang,Su Zhang,Chengyu Li,Hongjie Zhang
Cr3+-activated phosphors with high quantum efficiency show excellent promise in the field of near-infrared (NIR) phosphor converted light-emitting diodes (pc-LEDs). Here, we design an annealing program for Cr3+-doped phosphors containing variable valence elements that cannot be prepared in a reducing atmosphere to enhance their luminescence efficiency and thermal stability. A novel phosphor, Li2Mg3SnO6:Cr3+, developed by this annealing design, containing variable valence element Sn, exhibits higher quantum efficiency and better thermal stability than the one prepared by the conventional solid-state reaction. The Li2Mg3SnO6:0.03Cr3+ sample exhibits broadband NIR emission with a full width at half-maximum (FWHM) of 201 nm. After annealing, the internal quantum efficiency (IQE) and external quantum efficiency (EQE) of the Li2Mg3SnO6:0.03Cr3+ sample are enhanced from 48.5% to 84.7% and from 22.7% to 32.6%, respectively, and the thermal quenching temperature at which the luminescence intensity of the phosphor reduces to half of its initial value is promoted from ∼400 K to ∼425 K. The luminescence intensity of the optimized Li2Mg3SnO6:0.03Cr3+ sample at 425 K (∼152 °C) remains 49.2% of its initial intensity at 300 K. A NIR pc-LED is fabricated by combining the optimized Li2Mg3SnO6:0.03Cr3+ sample with a blue LED (455 nm blue chip), and the NIR radiant fluxes of 3.676 mW (at 10 mA) and 29.21 mW (at 100 mA), as well as a maximum NIR photoelectric efficiency of 14.2%, are obtained. The results show that this novel phosphor has great application potential in NIR pc-LEDs, and the annealing design exhibits huge potential for improving the optical properties of Cr3+-activated phosphors.
研究领域:
材料科学
·
光学工程
·
固体物理
·
光电子学
·
无机化学
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2019
·Vol. 7
·期 20
·1900774
·
IF 7.125
Xin Zhang,Dengbao Han,Chenhui Wang,Imran Muhammad,Feng Zhang,Ali Shmshad,Xulan Xue,Wenyu Ji,Shuai Chang,Haizheng Zhong
The in situ fabricated perovskite nanocrystals (PNCs) obtained through spin-coating a precursor solution are suitable candidates to achieve efficient perovskite light emitting diodes (PeLEDs). In this work, the solvent effects of on-chip crystallization are investigated by correlating the nucleation and growth process of in situ fabricated formamidinium lead iodide (FAPbI 3 ) nanocrystals with their optical and electronic properties. The FAPbI 3 nanocrystals obtained from a precursor solution in γ-butyrolactone (GBL) are smaller than those obtained from N , N -dimethylformamide and dimethyl sulfoxide, and the relatively weak coordination between GBL and the precursor molecules enables reduced defect states in the resulted PNCs with enhanced photoluminescence properties. A modified LaMer model is proposed to describe the solvent effects in the on-chip crystallization process. Based on these understandings, red emissive FA 0.87 Cs 0.13 PbI 3 nanocrystal films with absolute photoluminescence quantum yields up to 70% are realized. Finally, an efficient PeLED with maximum luminance of 218 cd m −2 and peak external quantum efficiency of 15.8% is achieved with good reproducibility.
研究领域:
材料科学
·
纳米科技
·
光电子学
·
半导体器件
·
凝聚态物理
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2022
·Vol. 10
·期 13
·2200276
·
IF 10.05
Chenwei Liu,Yongjie Liu,Shuxin Wang,Jiwei Liang,Cheng Wang,Fang Yao,Weijun Ke,Qianqian Lin,Ti Wang,Chen Tao,Guojia Fang
Quasi-two-dimensional (quasi-2D) perovskite light-emitting diodes (PeLEDs) are considered as one of the most potential candidates in electroluminescence territory owing to their unique quantum confinement effect and excellent thermal stability of the light. Nevertheless, heterogeneous energy domain distribution leads to severe non-radiative recombination in the process of energy transfer, which enormously hinders the performance and application of PeLEDs. Herein, an ambipolar amino acid, 5-aminovaleric acid (5AVA), is demonstrated to be able to coordinate lead and halides simultaneously with its carboxyl and amidogen groups. The coordinated ambipolar molecule not only reconstitutes energy domains of perovskites but also minimizes the interfacial defects of PeLEDs. Accordingly, the presence of 5AVA in perovskite precursors leads to dramatic suppression of the n = 1 and n = 2 phases and accelerates energy transfer from wide bandgap domains to narrow bandgap ones. As a result, maximum external quantum efficiency (EQE) of 19.3% (18.20% ± 1.10%) is achieved in quasi-2D green PeLEDs with current efficiency of 61.7 cd A −1 .
研究领域:
材料科学
·
光电子学
·
纳米科技
·
半导体器件
·
凝聚态物理
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2019
·
IF 2.961
Run Wang,Yue Zhang,Fu-Xing Yu,Yajie Dong,Ya-Lan Jia,Xing-Juan Ma,Qiang Xu,Yanhong Deng,Zu-Hong Xiong,Chun-Hong Gao
An efficient perovkite light-emitting diode (PeLED) is fabricated by incorporating 1,3,5-tri (m-pyrid-3-yl-phenyl)benzene (TmPyPB) between the emitting layer (EML) and the electron transporting layer (ETL), where TmPyPB plays an indispensable blocking effect on both excitons and holes. It shows a maximum current efficiency of 9.37 cd/A, and the corresponding external quantum efficiency (EQE) of 2.42% with a saturated green color Commission International de I'Eclairage (CIE1993) coordinated of (0.1279, 0.7951) under a driving voltage of 6 V. Meanwhile, the operational lifetime of the TmPyPB-based PeLED is improved to about 2.6-fold to that of the one with only the traditional ETL of aluminum 8-hydroxyquinolinate (Alq 3 ). The enhancements of electroluminescence (EL) performance are mainly attributed to better confinement of both the holes and the excitons in the EML, and more balanced carrier transportation in the TmPyPB-based PeLED. This work offers a feasible strategy to develop high performance optoelectronic devices.
研究领域:
材料科学
·
光电子学
·
纳米技术
·
半导体器件
·
功能材料
✓ 已验证
DOI
高影响因子
PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION
·
2018
·Vol. 36
·期 1
·1800077
·
IF 4.384
Yiqi Zhuang,Linlin Liu,Xiaoyan Wu,Yu Tian,Xuehong Zhou,Shuping Xu,Zengqi Xie,Yuguang Ma
The “far-field” surface plasmon resonance (FSPR) of metal nanoparticles, which have built a facile way to emission enhancement of red, green, blue, and white with nice reproducibility, has big potential application in solution-processed organic light-emitting diodes (OLEDs). According to the theory of the “far-field” effect, the reflectivity of the metal surface and the phase shift at the reflection play an important role in enhancing ratio, which strongly relate to the size and shape of nanoparticles. In this work, gold nanospheres with different sizes and nanorods are synthesized in order to determine the size and shape effect of FSPR. The results demonstrate that the one with higher reflectivity in a certain range induces a better emission enhancement in the luminous efficiency and the maximum brightness. The nanoparticles with bigger sizes and shape of rods have higher reflectivity, which is consistent with the simulation based on FSPR effect. The phase shifts of different nanoparticles are optimized by the distance between gold nanoparticles and emitters. The metal NPs with a high reflectivity and the applicable phase shift will have big potential for the emission enhancement in OLEDs.
研究领域:
纳米光学
·
材料科学
·
光电子学
·
表面等离子体学
·
有机光电子器件
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2020
·Vol. 22
·期 23
·13214-13222
·
IF 3.43
Yongfang Yuan,Xiaowen Zhang,Dongliang Li,Xiuyun Zhang,Lihui Wang,Zongliu Lu,Liming Liu,Feng Chi
Hole injection governs the efficiency of ultraviolet organic light-emitting diodes (UV OLEDs) due to the deep highest occupied molecular orbital level of the emissive molecule. Tungsten oxides (WOx), transition metal oxides with high work functions and good stability, cast light on solving this problem. By a low-cost, scalable and high-throughput manufacturing process, herein the facile synthesis of a WOx solution and its doping in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS + WOx) is systematically investigated for assembling efficient UV OLEDs. X-ray diffraction, atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy measurements confirm that WOx and PEDOT:PSS + WOx have good film morphology and exceptional electronic properties, such as the oxygen deficiency dominated non-stoichiometry of WOx. With PEDOT:PSS + WOx tailoring hole injection and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as the emitter, the UV OLEDs show outstanding electro-optic performance, with a radiance of 3.98 mW cm−2, external quantum efficiency of 2.30%, electroluminescence peak at 400 nm and full width at half maximum of 47 nm, which is superior to the performance of the corresponding reference materials. The mechanism of charge transfer from the PEDOT polycation to WOx, enhancing conductivity, is responsible for the robust hole injection/transport and is further elucidated by ultraviolet photoelectron spectroscopy and impedance spectroscopy, contributing to the optimization of the carrier balance and recombination zone. Our results illustrate an alternative approach for boosting UV OLED performance and advancing organic electronics.
研究领域:
材料科学
·
有机电子学
·
薄膜器件
·
光电功能材料
·
半导体器件物理
✓ 已验证
DOI
高影响因子
ORGANIC ELECTRONICS
·
2017
·
IF 3.399
Shihao Liu,Xiang Zhang,Shirong Wang,Haiwei Feng,Jiaxin Zhang,Huishan Yang,Letian Zhang,Wenfa Xie
Hybrid organic light-emitting devices (OLEDs) employing inorganic oxides as carrier transport layer can further improve the performances of OLEDs, such as power efficiency, reduce turn-on voltage and enhance stability. Vacuum thermal evaporating (VTE) and ultrasonic spray coating (USC) molybdenum trioxide (MoO 3 ) films with the thickness of 60 nm are used as hole transport layer (HTL) to realized hybrid OLEDs. USC-MoO 3 based OLED performs much better than VTE-MoO 3 based OLED. Atom forces microscope images shows that both VTE-MoO 3 film and emitting layer deposited on it have an extremely rough surface, offering convenient entrance ports for the intrusion of oxygen and water vapor into organic function layer. Nevertheless, USC MoO 3 film and emitting layer deposited on it exhibit much smoother surface so that oxygen and water vapor must completely destroy the metal cathode before they intrude in the organic function layers. Besides, to prevent MoO 3 quenching excitons , host material with excellent hole transport property is used to restrict exciton recombination region at the interface between emitting layer and electron transport layer. As a result, hybrid OLEDs employing USC-MoO 3 as HTL are realized with low turn-on voltage, improved efficiency and stability.
研究领域:
材料科学
·
纳米科技
·
电子器件
·
表面工程
·
光电功能材料
✓ 已验证
DOI
高影响因子
Nanoscale
·
2019
·Vol. 11
·期 36
·16907-16918
·
IF 6.97
Hong Lin,Jian Mao,Minchao Qin,Zhilong Song,Wanjian Yin,Xinhui Lu,Wallace C. H. Choy
While red is one of the primary colors for display applications, the investigation of visible red emitting perovskites, particularly 2D perovskites, is relatively limited. In this work, we demonstrate a single-phase Ruddlesden–Popper quasi-2D (C3H7NH3)2CsPb2I7 perovskite for red color LEDs. Through increasing the annealing temperature of (C3H7NH3)2CsPb2I7 perovskite thin films, we have successfully achieved tunable emission wavelengths from 654 to 691 nm. Equally important, for all the quasi-2D perovskite LEDs, once the annealing temperature is fixed, the emission spectrum is independent of bias voltages, which is very important for their use in lighting and displays. With the analysis of the crystallinity, morphology, and thermodynamic stability of the quasi-2D perovskite, we find that the obtained (C3H7NH3)2CsPb2I7 perovskite is a single-phase quasi-2D perovskite with only n = 2 phase. Besides, we found that the red shifting of emission wavelength is caused by the increase of perovskite crystal size while increasing the annealing temperature. Our results also show that the temperature-induced color tunability can be applied to a series of quasi-2D perovskites with different alkylammonium cations. Importantly, we find that short alkylammonium spacers offer better electrical properties for efficient current transport and high performance in LED applications. This work contributes to controlling the optoelectronic properties of quasi-2D perovskites via controlling their crystal growth as well as paves the way to realize practical lighting and display applications of perovskite LEDs.
研究领域:
材料科学
·
光电功能材料
·
半导体器件
·
纳米结构材料
·
固态照明
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2023
·
IF 3.6
Bingkai Gao,Lei Zhang,Runqiu Peng,Panlai Li,Qian Wu,Zhijun Wang
The exploration of performance luminescence near-infrared (NIR) material is crucial for rapidly developing NIR spectroscopic techniques. Herein, the NIR LaMg 0.5 Sn 0.5 O 3 :Cr 3+ phosphor was synthesized by a high temperature solid-state method. And its luminescence performance were improved by [In 3+ -Sc 3+ ] substituting for [Mg 2+ -Sn 4+ ]. The half-peak width can be expanded to 211 nm, the emission intensity can reach the seven times of that un-substitution, and the emission intensity at 423 K was maintained at 60 % of that at room temperature , moreover, the internal quantum efficiency can reach 54.2 %. On this basis, the phosphor converted light emitting diodes ( pc -LEDs) were achieved by combining La(Mg 1-x Sn 1-x In x Sc x ) 0.5 O 3 :Cr 3+ with blue LED, importantly, it can be applied to the biodetection and night vision lighting, which indicate its application value.
研究领域:
材料科学
·
生物医学工程
·
光学材料
·
分子影像
·
转化医学
·
光电子学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）