JOURNAL OF SOLID STATE CHEMISTRY
·
2020
·
IF 2.726
Dehai Liang,Xin Lian,Xianli Li,Binbin Luo
Two dimensional (2D) hybrid metal halide perovskites (MHPs) with broadband emission have attracted enormous attention, which is highly promising for single-component solid state lighting. However, it remains a challenge to unveil the underlying origin of broadband emission and achieve high quantum yield (QY). Herein, 2D single-layered [NH 3 (CH 2 ) 4 NH 3 ]CdBr 4 (Cd–P) has been successfully prepared. By partially replacing Cd 2+ with Pb 2+ , the energy band of Cd–P shows a transformation from indirect to direct, supported by the density functional theory (DFT) calculations. Benefiting from the change of energy band, alloyed Cd x Pb 1-x -P shows an intensive broadband emission spanning the whole visible range with a maximum of photoluminescence (PL) QY of 58%. Temperature-dependent and time-resolved PL uncover that the broadband emission origins from the coupling between free excitons (FEs) and [CdBr 6 ] 4- octahedra , instead of [PbBr 6 ] 4- . These findings provide a deep insight into the origin of STEs emission and an effective approach to promote the broadband emission for Cd-based MHPs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Dan Zhao,Shi-Rui Zhang,Yan-Ping Fan,Bao-Zhong Liu,Ya-Nan Li,Lin-Ying Shi,Shao-Jie Dai
Developing broad-band-emitting phosphors is very important to light-emitting diode (LED) lighting and displays. We introduced Eu2+ to solid solutions K2YZr1–yHfy(PO4)3 with a langbeinite-type structure to prepare a series of new phosphors. In this structure, two K+ sites could be occupied by Eu2+ cations to provide two different kinds of coordination environments, leading to broad emitting bands in the range of 390–700 nm. The coordination circumstance of Eu2+ was analyzed by Gaussian fitting and time-resolved emission spectra. Furthermore, the emitting intensity and thermal stability can be improved by modulating the crystalline field via substituting Zr4+ by Hf4+. When the Zr4+ was fully substituted by Hf4+, the external quantum efficiency increased by 53.75%, giving a bright cyan emission. Finally, an archetype white-LED lamp was made using cyan phosphor K2YHf(PO4)3:0.04Eu, red phosphor CaAlSiN3:Eu2+, and a 365 nm LED chip, which realized an applicable color rendering index (Ra = 81) and a correlated color temperature (CCT = 3792 K).
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 26
·9030-9036
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IF 6.4
Jinyi Wang,Xudong Wang,Chenjie Zhang,Xinyu Zhang,Tianliang Zhou,Rong-Jun Xie
Near-infrared (NIR) phosphors play a key role in phosphor-converted NIR emitters, but to find broadband phosphors still remains a great challenge due to the lack of strategies for screening appropriate hosts. Herein, we report a broadband Sr6Sc2Al4O15:Cr3+ NIR phosphor by choosing a host that has crystallographic sites accommodated for both Ce3+ and Cr3+ simultaneously. The emission spectrum of Sr6Sc2Al4O15:Cr3+ covers the region of 600–1500 nm, having a maximum at 860 nm and a full width at half-maximum (FWHM) of 241 nm. A NIR pc-LED was fabricated by combining the Sr6Sc2Al4O15:Cr3+ phosphor with a blue LED, which can produce a NIR output power of 0.16 mW driven at 750 mA. The fabricated NIR emitter demonstrates a good suitability in night vision and non-destructive detection.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2020
·
IF 4.825
Dan Zhao,Shi-Rui Zhang,Yan-Ping Fan,Bao-Zhong Liu,Rui-Juan Zhang
The relationship between the structure and properties is always a hot topic in the luminescent material field. In this work, a new phosphor KBa2(PO3)5:Eu2+ (KBP:Eu) was prepared by a high-temperature solid-state reaction method and characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy, photoluminescence (PL), and electroluminescence studies. The polyphosphate host KBP offers three lattice environments (K1, Ba1, and Ba2) for Eu2+ ions to realize broad-band emission from 380 to 700 nm under 345 nm excitation. The distributions of Eu2+ in the three lattice sites can be proven by low-temperature PL and transient fluorescence spectroscopy. Furthermore, temperature-dependent luminescence studies for phosphor KBP:0.02Eu reveal that its luminescence intensity at 150 °C retains about 97% of the initial value at 25 °C. By composing a 365 nm UV chip and KBP:0.02Eu, CaAlSiN3:Eu2+ phosphors, a warm white-light-emitting diode (WLED) was obtained with a correlated color temperature of 5146 K and chromaticity coordinates (0.3404, 0.3384). Therefore, KBP:Eu phosphor is a potential cyan-emitting phosphor used for high-power WLEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 40
·14342-14351
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IF 4.39
Shixiang Huang,Feng Zhang,Zhangyue Wu,Ying Fu,Chao Li
Motivated by the growing demand for noncontact temperature sensing in cryogenic environments, the development of a high performance low temperature optical thermometer has become more and more urgent. Herein, we demonstrate a new broadband emitting bismuth singly activated Ba2ZnSc(BO3)3 optical thermometric material that exhibits a remarkable temperature-dependent emission color variation and a good low temperature sensing performance. First, Bi3+ doped Ba2ZnSc(BO3)3 phosphors were successfully synthesized by a high-temperature solid-state reaction. Upon excitation at 320 nm, the emission spectra of Ba2ZnSc(BO3)3:Bi3+ cover almost the entire visible region from 350 to 720 nm because of the multiple crystallographic sites occupied by Bi3+ ions, which have been verified by structure analysis and time-resolved emission spectroscopy. Interestingly, the temperature dependent emission characteristics indicated that the thermal quenching phenomena of Bi3+ at different lattice sites were different, resulting in a very sensitive emission color variation from orange to cyan. Further analysis indicated that these Bi3+ doped luminescent materials showed a good performance in temperature sensing over a wide temperature range from 10 to 374 K, with a maximum relative sensitivity of 3.076% K−1 at 210 K. Finally, this study provides a new perspective for the design of superior thermosensitive phosphors, aimed toward non-rare earth ion doped thermosensitive phosphors for optical cryothermometry applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Xueyun Liu,Cuimei Cheng,Na Zeng,Xiaoman Li,Qing Jiao,Changgui Lin,Shixun Dai
In comparison to narrow-band upconversion (UC) luminescence from lanthanide-doped systems, broadband UC emission enables a broad and tailorable emissive color, which is desirable for tunable lasers and multicolor display applications. Herein, dual continuous broadband UC emission covering the visible spectral region at 480–720 nm has been achieved for the first time in Yb 3+ /Mn 2+ co-doped glass ceramics (GCs) functionalized with the precipitation of dual-phase γ -Ga 2 O 3 / β -YF 3 nanocrystals . A tunable UC emissive color from yellowish to orange could be obtained under 980 nm excitation by varying the Mn 2+ doping content and heat treatment temperature of GCs. We ascribe this phenomenon to the typical transition of exchange-coupled Yb 3+ -Mn 2+ dimers in tetrahedral and octahedral ligand environments. The Stokes and power-dependent UC luminescence properties, fluorescence lifetimes, site occupation and the involved UC mechanism are discussed in detail. This research contributes to a better understanding of the UC process between Yb 3+ and Mn 2+ in transparent hosts and provides a novel perspective for designing broadband-emitting UC materials.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2021
·Vol. 9
·期 24
·2101423
·
IF 9.926
Hao Hu,Yingmeng Liu,Zuoxiang Xie,Zewen Xiao,Guangda Niu,Jiang Tang
The luminescent property of 2D perovskite materials promotes their applications in light emitting diodes, phosphor powders, and scintillators. Recently, an interesting extrinsic low-energy broadband luminescence is hotly investigated. However, the understanding of such emissions is still at the early stage. In this study, based on a modified solvent evaporation method, centimeter-size (BDA)PbI 4 (BDA = NH 3 C 4 H 8 NH 3 2+ ) single crystals are grown which, besides the band–band emission, show a large Stokes-shifted broadband luminescence. We find such emission can be effectively excited by sub-gap photons and conclude defects-induced shallow traps are the corresponding luminescence centers. Density functional theory (DFT) calculations indicate that in-plane iodine vacancies can introduce shallow electron traps in the band gap and give rise to the broadband emission.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 26
·9841-9848
·
IF 8.067
Jindong Cao,Jiawei Lin,Kunjie Liu,Yan Xiong,Na Wang,Shihui He,Xusheng Zhang,Zhongnan Guo,Xin Chen,Jing Zhao,Quanlin Liu
As an emerging material, organic–inorganic metal halides (OIMHs) have been widely studied in the field of optoelectronics in recent years. In this work, a series of compounds (TMEDA)3(SbxBi1−x)2Cl12·H2O (0.1 ≤ x ≤ 0.6) (TMEDA = N,N,N′-trimethylethylenediamine) were synthesized. The incorporation of Sb3+ greatly enhanced the photoluminescence quantum yield of (TMEDA)3Bi2Cl12·H2O from 1% to 38%. The variation in the degree of distortion of the inorganic octahedra and the relatively suitable distances between metal ions are considered to be the reasons for the intense emission. (TMEDA)3(SbxBi1−x)2Cl12·H2O (0.1 ≤ x ≤ 0.6) exhibited a yellow phosphorescence emission at 605 nm and 595 nm under excitation at 305 nm and 375 nm, respectively. With the incorporation of Sb3+, changes in the emission intensity under different excitation wavelengths showed different trends. Thus, we attribute the yellow broadband emissions to the triplet emission of Bi3+ and Sb3+. Finally, we combined (TMEDA)3(Sb0.5Bi0.5)2Cl12·H2O with commercial phosphors and a near-ultraviolet light-emitting diode chip to prepare a white-light-emitting diode device, which exhibited a high color-rendering index of 94.4. The aim of our work was to investigate the structural effects of the photoluminescence of Sb3+-doped OIMHs and to further explore ways to improve the Sb3+ emission efficiency in the field of photoluminescence of OIMHs.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2021
·
IF 9.811
Yaxin Xu,Xingchen Chai,Wantian Yang,Jiarui Hu,Junnian Chen,Yunbin He
Lead-free zero-dimensional (0D) hybrid bismuth halide perovskites have aroused great interest due to their promising emission properties and good chemical stability. Herein, we report the design and synthesis of mixed-cation-phase 0D guanidinium–formamidinium bismuth chloride, [C(NH2)3]2[CH(NH2)2]3Bi2Cl11 (denoted as Gua2FA3Bi2Cl11), where an individual corner-sharing [Bi2Cl11]5– dimer is completely isolated and surrounded by the mixed Gua+ and FA+ organic cations. The corner-sharing connectivity mode in Gua2FA3Bi2Cl11 differs from that in pristine Gua3BiCl6, featuring an isolated [BiCl6]3– unit. Importantly, Gua2FA3Bi2Cl11 yields remarkable broadband emission spanning from 350 to 750 nm, different from the pristine Gua3BiCl6, showing distinct narrowband emission. Further investigation of photophysical properties reveals that the broadband emission has contributions from both free excitons and self-trapped excitons. Moreover, Gua2FA3Bi2Cl11 not only exhibits excellent photostability under continuous high-power UV lamp irradiation during 70 min but also is humidity stable for over 6 months under ambient conditions. This finding presents a novel molecular engineering strategy for the development of eco-friendly and stable 0D perovskite broadband emitters.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 8
·1692-1700
·
IF 7.779
Decai Huang,Xianguo He,Jingrong Zhang,Jie Hu,Sisi Liang,Dejian Chen,Kunyuan Xu,Haomiao Zhu
In recent years, near-infrared phosphor-converted light emitting diodes (NIR pc-LEDs) have been emerging as a promising compact and efficient NIR light source for a variety of applications such as sensing, bioimaging and food analysis. However, the development of broadband NIR phosphors with both high emission efficiency and excellent photoluminescence (PL) thermal stability is still facing a great challenge. Herein, a blue light excitable AlP3O9:Cr3+ phosphor with a broadband NIR emission covering 650–1000 nm is presented. In particular, in situ variable-temperature XRD measurements demonstrate that the AlP3O9:Cr3+ phosphor shows a near zero thermal expansion in the temperature range of 300–423 K, which is beneficial for achieving good PL thermal stability. The experiment shows that ∼91% of the PL intensity is retained at 423 K compared to that at room temperature, verifying our hypothesis. An efficient NIR pc-LED is fabricated by using the AlP3O9:Cr3+ phosphor and commercial blue diode chips, generating a NIR radiant flux of 29.5 mW at 60 mA drive current. Finally, the NIR pc-LED was successfully used as the light source for identifying spoiled eggs based on the NIR spectroscopic technique. This work provides a strategy to achieve high performance NIR phosphor systems.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Shifang Wang,Mingzheng Sun,Xiaolang Fan,Bowei Liu,Chuangchuang Qiao,Shuang Jing,Xufeng Zhou,Wei Li,Yangbo Wang,Huaiyong Li
Broad band near-infrared (NIR) emitting phosphors activated with Cr 3+ ions hold great potential for diverse applications. Microcrystalline barium gallate powders activated with Cr 3+ were synthesized, and their phase structure, photoluminescence properties as well as their potential uses in luminescence thermometry and plant cultivation, are investigated. It is revealed that Ba 1.3 Ga 12 O 19.3 : Cr 3+ exhibits high efficiency NIR emission in the 650–950 nm range upon blue excitation. At 80 K, the emission is dominated by narrow-peaks resulting from 2 E→ 4 A 2 transition. However, as the temperature rises, thermal coupling between the 2 E and 4 T 2 states leading to increased population of 4 T 2 state, the emission transforms into broad-band. At the same time, a significant decrease in lifetime is observed. This is attributed to the substantial difference in the transition probabilities of 2 E and 4 T 2 states, as well as the initiation of the nonradiative process, specifically the crossover from the 4 T 2 to the 4 A 2 state. Luminescence thermometers based on both luminescence intensity ratio (LIR) and lifetime of Ba 1.3 Ga 12 O 19.3 : 0.45 % Cr 3+ are proposed. High relative sensitivities of 6.78 %·K −1 at 113 K, and above 1 %·K −1 until 293 K is achieved from the LIR-based thermometer, and high values (ca. 1 % K −1 ) over a wide temperature range of 173–573 K are achieved from the lifetime readout.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Chemistry
·
2023
·
IF 7.3
D. Ma,Y. Lan,D. Zhang,X. Qin,Z. Yang,H. He,X. Dai,Z. Ye,X. Cao
Organic-inorganic perovskite materials have shown excellent performance and strong competitiveness in high-performance photovoltaic and optoelectronic devices. Besides the color-tunable and narrow-band emissions realized in hybrid perovskites, broadband emission from lead-halide perovskites has also attracted strong interest for applications in the next generation of solid-state lighting. Although great progress has been made in lead halide perovskites, a very important aspect that hinders their commercial exploitation is the severe lead toxicity. In this research, a lead-free copper(I)-iodine hybrid was synthesized by a solution evaporation method at room temperature. Single crystal X-ray diffraction shows that this hybrid possesses the chemical formula of C 6 H 5 CH 2 CH 2 NH 3 CuI 2 . The C 6 H 5 CH 2 CH 2 NH 3 CuI 2 belongs to the monoclinic phase with the C2/c space group, where the edge-sharing [CuI 4 ] tetrahedral chains are separated by organic C 6 H 5 CH 2 CH 2 NH 3 + ions, exhibiting one-dimensional (1D) crystal structure. The optical band-gap of C 6 H 5 CH 2 CH 2 NH 3 CuI 2 was determined to be 4.02 eV. The photoluminescence (PL) spectrum shows a broadband emission ranging from 380 nm to 780 nm and peaks at 542 nm together with a small peak at 336 nm, which can be attributed to the emission of self-trapped exciton (STE) and free exciton (FE), respectively. The large Stokes shift of 230 nm between the PL and photoluminescence excitation (PLE) as well as the broad emission was ascribed to the Jahn–Teller lattice distortion of [CuI 4 ] tetrahedra. The reduced 1D characteristic facilitates the tetrahedral distortion. PL decay analysis shows that the average lifetime of STE is about 66.9 ns? Temperature and time-dependent PL measurements show that the normal working temperature of this luminescent material should be no higher than 100 °C. Theoretical calculations were performed to better understand this compound. The successful synthesis and preliminary optical investigations on C 6 H 5 CH 2 CH 2 NH 3 CuI 2 can be of great significance for offering more environmental-benign options in both solid-state lighting and other perovskite optoelectronic devices.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）