- 标题
- 摘要
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- 实验方案
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Reducing current fluctuation of Cs3Bi2Br9 perovskite photodetectors for diffuse reflection imaging with wide dynamic range
摘要： Recently, the newly booming metal halide perovskites have attracted extensive attention worldwide due to their outstanding optoelectronic performance, and are expected to be ideal candidates for photodetectors (PDs). However, there is still lack of perovskite PDs-based imaging devices coming into commercialization stage, due to some practical reasons including toxicity brought by lead-based perovskites and the large light current fluctuations. In this paper, for the first time we fabricate a lead-free Cs3Bi2Br9 perovskite PD, and build a prototype of this perovskite PD-based imaging system with diffuse reflection imaging mode. Moreover, we propose a new parameter F related to light current fluctuation to evaluate imaging performance of a PD especially for weak diffuse light condition, and prove its usability by comparison of unoptimized lead-free Cs3Bi2Br9 perovskite PD and atomic layer deposition (ALD) optimized Cs3Bi2Br9 PD. ALD-optimization can improve the quality of perovskite film and suppress the dark current and current fluctuation. Finally, we obtain satisfactory diffuse reflection images of 2D and 3D objects with wide dynamic range. Therefore, the ALD-optimized Cs3Bi2Br9 PD has addressed two major concerns about perovskite PDs-based imaging devices, that may extend application of perovskite materials and improve imaging quality.
关键词： Current fluctuations,Photodetectors,Diffuse reflection imaging,Cs3Bi2Br9 perovskites
更新于2025-09-23 15:19:57
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Scanning laser terahertz near-field reflection imaging system
摘要： We developed a scanning laser terahertz (THz) near-field reflection imaging system using a fiber-coupled femtosecond laser source for high spatial resolution measurements without any sub-wavelength probes. In this system, THz wave pulses generated at the laser focusing spot in a non-linear optical crystal interact with a sample set on the crystal. Using this system, we obtained the THz reflection images of metallic structures with a resolution of ～λTHz/34 (λTHz = 680 μm) and also observed paraffin-embedded human breast tissue of several 10 μm in size. These results promise that this system can be suitable for industrial applications which require micron-scale resolution.
关键词： near-field,terahertz,reflection imaging,femtosecond laser,high spatial resolution
更新于2025-09-12 10:27:22
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In situ reflection imaging and microspectroscopic study on three-dimensional crystal growth of L-phenylalanine under laser trapping
摘要： We investigate growth behavior of an L-phenylalanine crystal formed by laser trapping with the use of reflection imaging and microspectroscopy. Optical reflection micrographs show colored images of the crystal due to constructive interference of incident white light. The color distribution on the crystal is dynamically changed under laser trapping, which is in addition to enlargement of the crystal plane area. The temporal change in the crystal thickness is examined by measuring reflection spectra of the crystal. We discuss the three-dimensional crystal growth under laser trapping by comprehensively considering the changes in crystal thickness and crystal plane area.
关键词： reflection imaging,laser trapping,L-phenylalanine,crystal growth,microspectroscopy
更新于2025-09-11 14:15:04