Mixed‐Cation MA x Cs 1− x PbBr 3 Perovskite Single Crystals with Composition Management for High‐Sensitivity X‐Ray Detection

2020 ◽  
Vol 14 (10) ◽  
pp. 2000226 ◽  
Author(s):  
Zhengfang Fan ◽  
Jiang Liu ◽  
Wentao Zuo ◽  
Guoqiang Liu ◽  
Xulin He ◽  
...  
2020 ◽  
Vol 8 (4) ◽  
pp. 1248-1256 ◽  
Author(s):  
Hongjian Zhang ◽  
Fangbao Wang ◽  
Yufei Lu ◽  
Qihao Sun ◽  
Yadong Xu ◽  
...  

High-sensitivity X-ray detectors made of solution grown CsPbBr3 single crystals with high crystalline quality was reported in this work. The device with asymmetric electrodes configuration shows high sensitivity of 1256 μC Gy−1 cm−2.


Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yilong Song ◽  
Liqi Li ◽  
Weihui Bi ◽  
Mingwei Hao ◽  
Yifei Kang ◽  
...  

Organic-inorganic halide perovskites (OIHPs) are recognized as the promising next-generation X-ray detection materials. However, the device performance is largely limited by the ion migration issue of OIHPs. Here, we reported a simple atomistic surface passivation strategy with methylammonium iodide (MAI) to remarkably increase the ion migration activation energy of CH3NH3PbI3 single crystals. The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects, while not introducing extra mobile ions, which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100 V mm-1. The X-ray detectors hence exhibit a record-high sensitivity above 700,000 μC Gyair‐1 cm‐2 under continuum X-ray irradiation with energy up to 50 keV, which enables an ultralow X-ray detection limit down to 1.5 nGyair s-1. Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yang Li ◽  
Wenyi Shao ◽  
Liang Chen ◽  
Juan Wang ◽  
Jing Nie ◽  
...  

AbstractLow-dimensional perovskite materials and their derivatives with excellent optical performance are promising candidates for light-emission applications. Herein, centimeter lead-halide Cs4PbBr6 single crystals (SCs), which have been used for radiation detection with the indirect conversion method, were synthesized by a facile solution process. The Cs4PbBr6 scintillator exhibits bright green emission peaking at 525 nm and a high photoluminescence quantum yield (up to 86.7%) under 375 nm laser excitation. The Cs4PbBr6 SCs exhibit high sensitivity to 40 keV X-rays, with a favorable linearity with the X-ray exposure dose rate, and the detection limit is as low as 64.4 nGyair/s. The scintillation time-response performance of the Cs4PbBr6 SCs was acquired by a time-correlated single-photon counting system under alpha-particle excitation. The Cs4PbBr6 SCs exhibit a very fast time response (τav = 1.46 ns) to alpha particles from a 241Am radiation source. This value is comparable to that of the commercial plastic scintillator EJ-228 (τav = 1.31 ns) and much faster than that of the LYSO(Ce) scintillator (τav = 36.17 ns). Conceptual X-ray imaging and alpha-particle pulse height spectroscopy experiments were also performed. These results demonstrated the potential of Cs4PbBr6 SCs for radiation detection applications, including X-ray imaging and charged particle detection with fast scintillation decay time and high sensitivity.


2022 ◽  
Vol 9 ◽  
Author(s):  
Anbo Feng ◽  
Shengdan Xie ◽  
Xiuwei Fu ◽  
Zhaolai Chen ◽  
Wei Zhu

Metal halide perovskite single crystals are a promising candidate for X-ray detection due to their large atomic number and high carrier mobility and lifetime. However, it is still challenging to grow large-area and thin single crystals directly onto substrates to meet real-world applications. In this work, millimeter-thick and inch-sized methylammonium lead tribromide (MAPbBr3) single-crystal wafers are grown directly on indium tin oxide (ITO) substrates through controlling the distance between solution surface and substrates. The single-crystal wafers are polished and treated with O3 to achieve smooth surface, lower trap density, and better electrical properties. X-ray detectors with a high sensitivity of 632 µC Gyair−1 cm−2 under –5 V and 525 µC Gyair−1 cm−2 under –1 V bias can be achieved. This work provides an effective way to fabricate substrate-integrated, large-area, and thickness-controlled perovskite single-crystal X-ray detectors, which is instructive for developing imaging application based on perovskite single crystals.


Author(s):  
M.T. Otten ◽  
P.R. Buseck

ALCHEMI (Atom Location by CHannelling-Enhanced Microanalysis) is a TEM technique for determining site occupancies in single crystals. The method uses the channelling of incident electrons along specific crystallographic planes. This channelling results in enhanced x-ray emission from the atoms on those planes, thereby providing the required site-occupancy information. ALCHEMI has been applied with success to spinel, olivine and feldspar. For the garnets, which form a large group of important minerals and synthetic compounds, the channelling effect is weaker, and significant results are more difficult to obtain. It was found, however, that the channelling effect is pronounced for low-index zone-axis orientations, yielding a method for assessing site occupancies that is rapid and easy to perform.


Author(s):  
D. A. Carpenter ◽  
M. A. Taylor

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.


2019 ◽  
Author(s):  
Chem Int

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.


Sign in / Sign up

Export Citation Format

Share Document