Chemosensors
·
2022
·Vol. 10
·期 12
·527
·
IF 4.229
Anheng Gu,Guo-Hui Pan,Huajun Wu,Liangliang Zhang,Ligong Zhang,Hao Wu,Jiahua Zhang
Orthorhombic ZrTiO4is an attractive dielectric material; its optical properties are, however, less known. In this paper, we reported on the microstructure and luminescence studies of pristine ZrTiO4and Eu3+-doped ZrTiO4phosphors. The results indicated that two types of TiO6octahedra, the isolated/ localized and coupled/delocalized, coexisted in host matrix. Eu3+doping could induce oxygen vacancy defect states located below the bottom of the conduction band. Pristine ZrTiO4showed bright yellow luminescence via STEs recombination at defects sites at low temperatures, but significant thermal quenching occurred due to STEs migration to quenching centers at elevated temperatures. Effective host sensitized energy transfer to Eu3+was observed in ZrTiO4:Eu3+phosphors and yielded the red characteristic emissions of Eu3+. Anomalous STEs luminescence enhancement and spectral blue-shift in the excitation spectra with higher Eu3 +concentration appeared and were explained by considering three factors: competitive absorption between electron transitions from the top of the valence band to the defect states and host conduction band, Eu3+doping driving the production of more isolated TiO6octahedra, and energy back-transfer from Eu3+activators to other titanate groups. On the basis of the dual-emitting combination strategy involving host STEs and Eu3+luminescence, ZrTiO4:Eu3+phosphors were demonstrated to be ratiometric self-referencing optical thermometric materials, with a working range of 153–313 K and a maxima of relative sensitivity to ~1.1% K−1at 243 K.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 11
·期 3
·1095-1102
·
IF 8.067
Chen Fang,Jiakai Yang,Guojun Zhou,Zhichao Zhang,Yingjie Mao,Xiangyan Yun,Libo Liu,Denghui Xu,Xiong Li,Jun Zhou
Rare earth ion doping in metal halides has been a promising method for imparting and tailoring their optical and optoelectronic performances towards versatile optical applications. In this work, the relationships among intrinsic self-trapped excitons (STEs), sub-band gap defects and rare earth ions Tb3+ in Cs2ZrCl6:Tb3+ perovskite variants were established. Cs2ZrCl6 exhibits dual emission, deriving from the intrinsic STEs and sub-band gap defects owing to the Zr4+ or Cl− vacancies, respectively. Doping Tb3+ facilitated the characteristic emission (5D4–7FJ=6,5,4,3) of Tb3+ ions and the energy transfer from STEs to Tb3+ ions. Moreover, the participation of defect states and thermally activated delayed fluorescence (TADF) might lead to a high concentration of STEs, which in turn causes the abnormal thermal quenching effect. These findings not only provide a more in-depth understanding of the luminescence properties of Cs2ZrCl6, but also provide a new direction towards achieving tunable emission colors based on the energy transfer from STEs to rare earth ions.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2016
·
IF 2.265
Wenjuan Bian,Wei Lu,Yushuang Qi,Xue Yu,Dacheng Zhou,Yong Yang,Jianbei Qiu,Xuhui Xu
The synergistic effect appeared due to the cooperative dual-wavelength excitation by near-infrared (NIR) and ultraviolet (UV) light in rare-earth doped nano-particles (NPs) is very important to improve solar cell efficiency. Herein, we studied the synergistic effect combined with the energy levels of Er 3+ ions and the defect states in KLu 2 F 7 NPs. The introduction of Ce 3+ ions in KLu 2 F 7 :16%Yb 3+ , 2%Er 3+ NPs results in significant improvement of synergistic effect by producing more vacancy defects ( V K ′ ) which serves as shallow traps. We verify unambiguously that the control of the defects distribution exerts a facile approach to promote the synergistic effect with the assistance of Ce 3+ ions doping.
研究领域:
材料科学
·
光物理
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 12
·3242
·
IF 5.076
Yu Sun,Jin Chen,Fengchao Wang,Yi Yin,Yan Jin,Jun Wang,Xiaogai Peng,Ruiyi Han,Canyun Zhang,Jinfang Kong,Jing Yang
Nowadays, Mn-doping is considered as a promising dissolution for the heavy usage of toxic lead in CsPbX3perovskite material. Interestingly, Mn-doping also introduces an additional photoluminescence band, which is favorable to enrich the emission gamut of this cesium lead halide. Here, a solution spraying strategy was employed for the direct preparation of CsPbxMn1−x(Br,Cl)3film through MnCl2doping in host CsPbBr3material. The possible fabrication mechanism of the provided approach and the dependences of material properties on Mn-doping were investigated in detail. As the results shown, Pb was partially substituted by Mn as expected. With the ratio of PbBr2:MnCl2increasing from 3:0 to 1:1, the obtained film separately featured green, cyan, orange-red and pink-red emission, which was caused by the energy transferring process. Moreover, the combining energy of Cs, Pb, and Mn gradually red-shifted resulted from the formation of Cs-Cl, Pb-Cl and Mn-Br coordination bonding as MnCl2doping increased. In addition, the weight of short decay lifetime of prepared samples increased with the doping rising, which indicated a better exciton emission and less defect-related transition. The aiming of current work is to provide a new possibility for the facile preparation of Mn-doping CsPbX3film material.Keywords:MnCl2doping;CsPbxMn1−x(Br,Cl)3;thin films;solution spraying
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2016
·
IF 2.933
Xiaokai Li,Xiaojian Mao,Minghui Feng,Junxi Xie,Benxue Jiang,Long Zhang
ZrO 2 is considered an efficient sintering additive for transparent Y 2 O 3 ceramics. However, the doping of tetravalent Zr 4+ ions leads to a dark brown color of the ceramic after vacuum sintering. In this study, the optical properties of vacuum-sintered and air-annealed ceramics were characterized using transmittance spectra and a Commission International de l’Eclairage (CIE) diagram. The corresponding defects are investigated by electron paramagnetic resonance (EPR) spectra. The band gap of the vacuum-sintered samples is 2.72 eV, which is much smaller than that of the annealed sample. The results reveal that the V O + (F + center) and Zr 3+ defects form transition energy levels near the top of the valence band and at the bottom of the conduction band , respectively. The color-related absorption is mainly attributed to the electronic transfer from the Zr 3+ level to the conduction band and from the F + center to the Zr 3+ level.
研究领域:
材料科学
·
无机非金属材料
·
光学材料
·
陶瓷材料
·
固体物理
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2018
·Vol. 7
·期 3
·1124-1137
·
IF 9.931
Liangxin Zhu,Chong Chen,Fumin Li,Zhitao Shen,Yujuan Weng,Qingsong Huang,Mingtai Wang
To improve the charge separation and transport efficiency in perovskite solar cells (PSCs) with a TiO2-based hybrid mesoscopic/planar architecture, CdS and Cd(SCN2H4)2Cl2 are incorporated into the CH3NH3PbI3 active layer through in situ synthesis to prepare CdS:Cd(SCN2H4)2Cl2:CH3NH3PbI3 bulk-heterojunction films for PSCs. The incorporated CdS and Cd(SCN2H4)2Cl2 improve the quality of perovskite films. Moreover, Cd(SCN2H4)2Cl2 can effectively reduce the defect state density on the CH3NH3PbI3 crystal surface, which decreases charge recombination and facilitates charge transport in PSCs. Furthermore, first-principles calculations show that the I atom of CH3NH3PbI3 has a strong interaction with the Cd atom of CdS, which induces interfacial charge redistribution and charge transfer at the CH3NH3PbI3/CdS interface and therefore decreases the energy of the CH3NH3PbI3:CdS composite system, leading to more efficient electron–hole separation and improved structural stability of the perovskite bulk-heterojunction film. For the above reasons, the CdS:Cd(SCN2H4)2Cl2:CH3NH3PbI3 bulk-heterojunction cell shows much higher efficiency and better stability than the PSCs with pure CH3NH3PbI3. The highest efficiency reaches 20.1%, which is 1.16 times that (17.3%) of the PSCs with pure CH3NH3PbI3 and is also much higher than those of previously reported CH3NH3PbI3 PSCs with a compact/mesoporous TiO2 film. Our research results may provide a new understanding for improving the structural stability and performance of PSCs.
研究领域:
材料科学
·
物理化学
·
太阳能技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Lu Chen,Jinxin Bian,Tiansheng Zhang,Xiaoyi Li,Ronghua Jian,Fan Wu
In this study, we employed lock-in amplifier-based surface photovoltage (SPV) spectroscopy to identify bandgap excitations, bound exciton states, and defect excitations in Cs 3 Bi 2 I 9 . This method, combined with SPV phase spectroscopy, enabled the evaluation of deep-level and shallow-level defects, correlating with charge-transfer transitions and defect-induced broad tailing absorption observed in the absorption spectrum. We found that deep-level defects in Cs 3 Bi 2 I 9 films can produce both positive and negative SPV signals, allowing for the simulation of excitatory and inhibitory synapses in neural networks and potential applications in robotic eye implants. By integrating Cs 3 Bi 2 I 9 thin films rich in deep-level defects, robotic eyes can generate execution and cancellation commands based on SPV responses to different light wavelengths. Our results demonstrate that defect states in Cs 3 Bi 2 I 9 are preparation-dependent, leading to broad tailing absorption and enabling the conversion of SPV signals via wavelength modulation. These results highlight the potential of Cs 3 Bi 2 I 9 in advanced optoelectronic applications.
研究领域:
材料科学
·
光学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ECS Journal of Solid State Science and Technology
·
2016
·Vol. 5
·期 9
·R137
·
IF 1.65
Wenjuan Bian,Yushuang Qi,Xuhui Xu,Dacheng Zhou,Yong Yang,Jianbei Qiu,Xue Yu
The influence of the introduction of Li+ ions on the upconversion (UC) properties of KLu2F7:Yb3+, Er3+ nanocrystalline has been investigated in detail. It is found that the UC emission intensity of 10 mol% Li+ ions doped KLu2F7:Yb3+, Er3+ nanocrystalline is enhanced about 13 times in comparison with that of Li+-free sample. Under the excitation of 980 nm laser diode (LD), a significant improvement of the green to red emission ratio (GRR) in the 10 mol% Li+-doped sample is observed by increasing pump power density. Li+ ions could occupy the cationic sites or the interstitial sites in the KLu2F7 host matrix, which probably eliminate the defect states via the charge compensation and tailor of the crystal field, leading to the promotion of the UC emission efficiency. Thus, the introduction of Li+ ions provides new opportunities for enhancing the scope of applications of Yb3+, Er3+ doped KLu2F7 nanocrystalline ranging from infrared solar cells to volumetric multiplexed bio-probe.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2015
·
IF 2.999
Xin Wang,Zhurong Liang,Xueqing Xu,Nan Wang,Jun Fang,Junxia Wang,Gang Xu
Highly Cu-rich copper indium sulfide (CuInS 2 , CIS) quantum dots were synthesized utilizing copper chloride (CuCl) and indium acetate (In(Ac) 3 ) as metal cation precursors, combined with n-dodecanethiol (DDT) as a coordinating sulfur source and solvent. With excess of In(Ac) 3 , i.e. with Cu/In ratios of 1/4, together with Zn 2+ ions post-treatment, a relatively high photoluminescence quantum yield (QY) of ∼73% with long average lifetime of ∼359 ns has been obtained, which is proposed to be attributed to the Cu-rich defect states in the CIS nanocrystals (NCs) nuclei. Meanwhile, the formation of In-rich CIS–ZnS alloy, i.e. Zn–Cu–In–S (ZCIS) with high density of Cu vacancies, combined with the surface passivation of ZnS overlay resulted in a high QY. Finally, the formation mechanism of the ZCIS/ZnS with Cu-rich nuclei has been proposed.
研究领域:
材料科学
·
纳米技术
✓ 已验证
DOI
高影响因子
Small
·
2021
·Vol. 17
·期 28
·2101403
·
IF 13.281
Qiqian He,Gaoyu Chen,Yongkai Wang,Xiaoyu Liu,Danting Xu,Xiangxing Xu,Ying Liu,Jianchun Bao,Xun Wang
All-Inorganic perovskite CsPbX 3 (X = Cl, Br, I) quantum dots (QDs) have attracted tremendous attention in the past few years for their appealing performance in optoelectronic applications. Major properties of CsPbX 3 QDs include the positive photoconductivity (PPC) and the defect tolerance of the in-band trap states. Here it is reported that when hybridizing CsPbX 3 QDs with indium tin oxide (ITO) nanocrystals to form CsPbX 3 -ITO nano-heterojunctions (NHJs), a voltage tuned photoresponse—from PPC to negative photoconductivity (NPC) transform—is achieved in lateral drain-source structured ITO/CsPbX 3 -ITO-NHJs/ITO devices. A model combining exciton, charge separation, transport, and most critical the voltage driven electron filling of the in-band trap states with drain–source voltage ( V DS ) above a threshold, is proposed to understand this unusual PPC-NPC transform mechanism, which is different from that of any known nanomaterial system. This finding exhibits potentials for developing devices such as photodetectors, optoelectronic switches, and memories.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2023
·
IF 3.9
Qiaocan Huang,Zunxian Yang,Yuanqing Zhou,Yuliang Ye,Bingqing Ye,Zihong Shen,Wenbo Wu,Zongyi Meng,Zhiwei Zeng,Hongyi Hong,Songwei Ye,Zhiming Cheng,Qianting Lan,Jiaxiang Wang,Ye Chen,Hui Zhang,Tailiang Guo,Fushan Li,Yongyi Chen,Zhenzhen Weng
Quantum dots (QDs) with an alloy shell (CdSe@ZnS/ZnS) are one of the most promising emitters for optoelectronic devices for their superior properties such as narrow full width at half maximum (FWHM), high color purity and tunable wavelength. However, the presence of lattice stresses during the internal growth of quantum dots can cause severe exciton bursts. Optimizing the ramp-up process during the core growth of quantum dots and rising the temperature when cladding with ZnS shells is an effective strategy for obtaining high-quality quantum dots. Besides, the stability of quantum dots is further modified by using 1-Octanethiol (OT) as ligands. Detailed analyses of the morphology, colloidal stability, and luminescence performance of QDs were represented. Finally, green CdSe@ZnS/ZnS QLEDs with prolonged carrier lifetimes and less defect state densities achieved peak luminescence at 361850 cd/m 2 with a current efficiency (CE) of 33 cd/A. This work provides a better understanding of the relationship between defect state density and the performance of quantum dots for designing and fabricating high-performance light-emitting diodes.
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yujia Hu,Yongsheng Sun,Shengran Hou,Dongdan Chen,Zhongmin Yang
Inorganic photochromic (PC) materials are gaining increasing recognition as promising candidates for applications in optical storage and information display. However, conventional photochromic materials exhibit sluggish coding rates and a deficiency in intelligent response for writing and erasing under multiple excitation sources. This deficiency contributes to suboptimal readout/decoding efficiency and storage security. Here, we show a Ba 2 NaNb 5 O 15 :Er 3+ photochromic material with photoluminescence reversible modulation that can fast respond to both ultraviolet light and 532 nm laser within about 1 s, which accompanied by thermal bleaching. The PC mechanism which is based on defect state exchanges between oxygen vacancy defects and color centers is attributed to the structural flexibility of Nb-O systems and oxygen vacancy increased under irradiation. More importantly, it shows differential PC decay behavior in response to X-ray and UV light due to the difference in the number of trapped carriers. Therefore, a simple strategy based on different self-recovery levels induced by double excitation is constructed to develop an encrypted optical memory model. This fast and differential excitation source response behavior hopefully stimulates the development of new encrypted optical memory.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）