JOURNAL OF APPLIED PHYSICS
·
2022
·Vol. 132
·期 3
·
IF 2.877
Guo Heng,Zhu Yizhi,Chen Jinping,Xie Xiaoyu,Jiang Qingsong,Xu Chunxiang,Cui Qiannan,Shi Zengliang
As an effective means to endow lead halide perovskite nanocrystals (NCs) with new properties, ion doping has been widely applied. Transition metal Mn-doped CsPbCl 3 is of particular interest, as the Mn doping introduces new emission bands, improves photoluminescence quantum yield (PLQY), and even enhances stability. However, it is still insufficient to catch insight of the energy transfer process and luminescence characteristics of these high defect tolerance NCs doped with Mn ion. Here, we systematically studied the energy transfer from exciton to Mn 2+ ions in Mn-doped CsPbCl 3 NCs by variable temperature steady-state fluorescence spectra and time-resolved spectra. The abnormal attenuation behavior of the exciton and Mn 2+ with the change of temperature was observed, from which we predict the existence of shallow traps near the conduction band and these shallow traps will affect the luminescence properties by influencing the energy transfer process. We show a simple physical model invoking only shallow trap states that uniquely describe the temperature-dependent energy transfer between the exciton and the Mn 2+ ion. The thermometric performance (30–290 K) was studied in terms of relative thermal sensitivity, in which the calculated relative sensitivity range is ∼0.12%–1% K −1 .
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
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
NANOTECHNOLOGY
·
2022
·Vol. 33
·期 34
·345709
·
IF 3.953
Beibei Jia,Jun Zhou,Yuqing Chen,Zepeng Lv,Haomin Guo,Zixuan Zhang,Zihe Zhu,Haoyu Yu,Yang Wang,Kai Wu
Charge transport in insulating composites is fundamental to designing high performance in electrical breakdown strength processes. A fundamental understanding of the charge transport at nanoscale in insulating composites remains elusive. Herein, we fabricate two types of interfaces in epoxy (EP) composites (Al2O3/EP and bubble/EP, respectively). Then the local dynamic charge mobility behavior and charge density are explored using in situ Kelvin probe force microscopy. After the external voltage in the horizontal direction is applied, significant differences are demonstrated in the evolution of charge transport for epoxy matrix, filler/bubble, and their interface, respectively. The interface between Al2O3 and epoxy is easier to accumulate the negative charges and introduce shallow traps. Lots of positive charges are located around a bubble where deeper traps are present and could prevent charge migration. Thus, this work offers extended experimental support to understanding the mechanism of charge transport in dielectric composites.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 31
·期 35
·2103978
·
IF 18.808
Wenchao Wang,Xueqin Bai,Qing Ci,Lili Du,Xingang Ren,David Lee Phillips
Undesired photoelectronic dormancy through active species decay is adverse to photoactivity enhancement. An insufficient extrinsic driving force leads to ultrafast deep charge trapping and photoactive species depopulation in carbon nitride (g-C 3 N 4 ). Excitation of shallow trapping in g-C 3 N 4 with long-lived excited states opens up the possibility of pursuing high-efficiency photocatalysis. Herein, a near-field-assisted model is constructed consisting of an In 2 O 3 -cube/g-C 3 N 4 heterojunction associated with ultrafast photodynamic coupling. This In 2 O 3 -cube-induced near-field assistance system provides catalytic “hot areas”, efficiently enhances the lifetimes of excited states and shallow trapping in g-C 3 N 4 and this favors an increased active species density. Optical simulations combined with time-resolved transient absorption spectroscopy shows there is a built-in charge transfer and the active species lifetimes are longer in the In 2 O 3 -cube/g-C 3 N 4 hybrid. Besides these properties, the estimated overpotential and interfacial kinetics of the In 2 O 3 -cube/g-C 3 N 4 hybrid co-promotes the liquid phase reaction and also helps in boosting the photocatalytic performance. The photocatalytic results exhibit a tremendous improvement (34-fold) for visible-light-driven hydrogen production. Near-field-assisted long-lived active species and the influences of trap states is a novel finding for enhancing (g-C 3 N 4 )-based photocatalytic performance.
研究领域:
材料科学
·
光催化
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2021
·Vol. 9
·期 30
·9619-9626
·
IF 7.393
Shenghui Zheng,Junpeng Shi,Xiaodan Wang,Xiaoyan Fu,Hongyong Fan,Hongwu Zhang
Here, we have developed a novel thermosensitive technique based on shallow-trap persistent luminescence to achieve high-resolution and long-duration texture imaging of fingerprints even through latex gloves. A thermosensitive flexible film that consists of a transparent silica gel embedded with a shallow-trap Bi2Ga4O9:Eu3+,Cr3+ (BGO) phosphor microarray exhibits broadband near-infrared PersL, which enables sensitive temperature sensing using a thermally stimulated luminescence (TSL) method. The uniform surface conical arrays of the BGO film ensure a high thermal sensing resolution. Only a simple touch is enough to induce thermal distribution that can be easily visualized as luminescence using an EMCCD camera. Furthermore, the BGO film responds rapidly to small temperature fluctuations with high sensitivity (8.10 ± 0.476% K−1), enabling fingerprint imaging even through latex gloves in only a few seconds. This imaging strategy is very promising for sensitive temperature sensing without power supply, and it also opens new application opportunities for shallow-trap PersL materials.
研究领域:
材料科学
·
光学工程
·
生物识别技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 10
·3037-3048
·
IF 6.641
Ju-Ping Ma,Ya-Meng Chen,Lu-Min Zhang,Shao-Qiang Guo,Jian-Dang Liu,Hong Li,Bang-Jiao Ye,Zhi-Yong Li,Yang Zhou,Bin-Bin Zhang,Osman M. Bakr,Jun-Ying Zhang,Hong-Tao Sun
Doping has been established as a powerful approach for endowing lead halide perovskite nanocrystals (NCs) with novel properties. However, our fundamental understanding of the local structure of dopants, doping efficiency and luminescence properties of these NCs is still very sparse. Here, we provide the first experimental evidence regarding the local structure of rare earth ions in CsPbCl3 NCs, based on the analysis of extended X-ray absorption fine structure spectroscopy. Our result suggests that Yb3+ occupies the Pb2+ crystallographic sites in CsPbCl3 NCs. We further demonstrate a strategy to examine the determinant of the doping efficiency in lanthanide-doped lead halide perovskite NCs, which enables us to uncover the important role of structural defects in affecting the doping efficiency. A broad range of experimental characterization techniques including steady-state and time-resolved luminescence spectra, X-ray absorption spectra, and positron annihilation lifetime spectra, coupled with first-principles calculations, help us identify that the doping efficiency is associated with structural defects in NCs and that the formation of a higher-concentration of defects favors incorporation of a higher-concentration of dopants into the lattice. Importantly, we demonstrate that the concept of defect-assisted doping is not limited to the model system of Yb3+-doped CsPbCl3 NCs, but can be used as a guideline to rationally tune the doping efficiency of lanthanide-doped halide perovskite NCs. We also show that lanthanide-doped CsPbCl3 NCs demonstrate anomalous decay of the band-edge emission, which we propose is due to the existence of shallow trapping states near the conduction band. Our results greatly deepen the understanding of the structural and photophysical properties of lanthanide-doped lead halide perovskite NCs, and highlight the possibility to use the chemistry of defects to tailor the doping efficiency of halide perovskite NCs.
研究领域:
材料科学
·
光物理学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 54
·48720-48727
·
IF 3.289
Yao Zhou,Jun Hu,Bin Dang,Jinliang He
Polymer nanocomposite dielectrics always attract widespread attention in electrical and electronic fields. Space charge suppression under direct current electric field is one of the key issues in developing high performance insulation materials. This paper reports a potential mechanism of space charge suppression in polypropylene/titanium oxide nanocomposites. Trap level distribution and space charge accumulation are obtained by thermally stimulated current and pulsed electro-acoustic method, respectively. The micro morphology and structure of the nanocomposites are examined by differential scanning calorimetry, X-ray diffraction and positron annihilation lifetime spectroscopy. The results indicate that doping of titanium oxide introduces numerous shallow traps and reduces the number of deep traps, which significantly suppresses space charge accumulation and increases conductive current. The results can be explained by the fact that shallow traps, resulting from the interfaces between nanoparticles and polymer matrix and the interaction between nanoparticles and the crystalline/amorphous interfaces, could increase the charge carrier mobility and reduce potential barrier for charge carrier transport. This potential mechanism is of great importance to understand the space charge suppression in polymer nanocomposites and in designing high performance nanodielectric materials.
研究领域:
高分子材料学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-12
·
IF 14.7
Zhang Renfu,Zhou Qinqi,Huang Siyuan,Zhang Yiwen,Wen Rui-Tao
Ion trapping has been found to be responsible for the performance degradation in electrochromic oxide thin films, and a detrapping procedure was proved to be effective to rejuvenate the degraded films. Despite of the studies on ion trapping and detrapping, its dynamics remain largely unknown. Moreover, coloration mechanisms of electrochromic oxides are also far from clear, limiting the development of superior devices. Here, we visualize ion trapping and detrapping dynamics in a model electrochromic material, amorphous WO 3 . Specifically, formation of orthorhombic Li 2 WO 4 during long-term cycling accounts for the origin of shallow traps. Deep traps are multiple-step-determined, composed of mixed W 4+ -Li 2 WO 4 , amorphous Li 2 WO 4 and W 4+ -Li 2 O. The non-decomposable W 4+ -Li 2 WO 4 couple is the origin of the irreversible traps. Furthermore, we demonstrate that, besides the typical small polaron hopping between W 5+ ↔ W 6+ sites, bipolaron hopping between W 4+ ↔ W 6+ sites gives rise to optical absorption in the short-wavelength region. Overall, we provide a general picture of electrochromism based on polaron hopping. Ion trapping and detrapping were demonstrated to also prevail in other cathodic electrochromic oxides. This work not only provides the ion trapping and detrapping dynamics of WO 3 , but also open avenues to study other cathodic electrochromic oxides and develop superior electrochromic devices with great durability.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Materials Horizons
·
2025
·
IF 10.7
Hengli Zhu,Jiaren Du,Weichang Li,Hengwei Lin
Rare-earth ion doped glass, exhibiting remarkable compositional flexibility and persistent luminescence (PersL), retains the superior attributes of traditional glass while showcasing extraordinary responsive properties, thereby expanding its applicability across diverse technological domains. However, despite numerous PersL materials displaying impressive afterglow intensity and prolonged decay duration under ambient conditions, their performance often deteriorates significantly at lower temperatures. These thermosensitive limitations hinder the ability of PersL materials to sustain their efficacy in cryogenic environments. In this study, we employed a facile microwave-assisted synthesis method to incorporate a significant quantity of uniformly distributed shallow traps (0.55–0.76 eV) into an Eu doped MgO–Al2O3–SiO2 vitreous matrix, thereby enabling efficient charge storage and release across a broad temperature range (−125 °C to 200 °C). This demonstrated that the density of shallow trap distribution surpasses that of the most prevalent commercial PersL materials emitting blue light, such as Sr2MgSi2O7:Eu2+,Dy3+ and CaAl2O4:Eu2+,Nd3+. X-ray irradiation markedly enhanced the blue PersL attributes and storage efficiency of the glass within the cryogenic temperature range (−125 °C to 0 °C). Therefore, the exceptional blue PersL properties, wide operational temperature range, and robust energy storage efficiency of the glass under X-ray excitation make it an optimal candidate for implementation in photonic data storage, ionizing radiation detection, and cryogenic safety signage applications. This study not only successfully develops a blue PersL glass matrix but also elucidates the PersL mechanism at cryogenic temperatures, providing an example for the design of other low-temperature PersL materials.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 33
·e52786
·
IF 3.057
Zelin Hong,Xiangrong Chen,Guangyu Zhu,Muhammad Awais,Yiwen Shi,Hanshan Zhu,Hao Li,Ashish Paramane
The effect of adding electron-buffering voltage stabilizer (1 wt% m-aminobenzoic acid) on the electrical tree-induced degradation of cross-linked polyethylene (XLPE) was studied at high temperatures. The electrical tree inception, growth, and partial discharge characteristics were simultaneously analyzed at 30, 50, and 70°C, respectively. The results showed that the growth rate of electrical tree and partial discharge activity as well as the discharge repetition rate, significantly increased with the temperature for pure XLPE and XLPE stabilizer blend. However, the XLPE stabilizer blend exhibited higher tree inception voltage, lower tree growth rate, and partial discharge activity than pure XLPE. The addition of the voltage stabilizer reduced the carbon layer thickness in the tree channel and offered higher resistance to the electrical tree growth. Surface potential decay demonstrated that the voltage stabilizer addition decreased the trap energy level, but increased the shallow trap density of the XLPE. Quantum chemical calculations showed that the voltage stabilizer enhanced the ability to buffer the high-energy electrons in the XLPE. A high-energy electron buffering mechanism was also proposed to explain the effect of voltage stabilizer on the electrical treeing and partial discharge activity in the XLPE at high temperatures.
研究领域:
材料科学
·
电气工程
·
聚合物化学
✓ 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）