Ultrafast microscopy and image segmentation of spatially heterogeneous excited state and trap passivation in Cu2BaSnSSe3
Ultrafast microscopy and image segmentation of spatially heterogeneous excited state and trap passivation in Cu2BaSnSSe3
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DOI：
10.1016/j.xcrp.2023.101601
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发表时间：
2023-09
影响因子：
8.9
通讯作者：
Hannah Luebbering;A. Shafiee;B. Teymur;Yongshin Kim;D. Mitzi;E. Ghadiri
中科院分区：
文献类型：
--
作者：
Hannah Luebbering;A. Shafiee;B. Teymur;Yongshin Kim;D. Mitzi;E. Ghadiri
地球上丰富的Cu 2BaSnS 4-xSex（CBTSSe）代表了Cu 2 ZnSn（S，Se）4在太阳能转换中的最新替代品，具有较低的无序和带尾。我们报告的异质性激发态和陷阱态图案在不同的解决方案处理CBTSSe薄膜使用超快双色泵浦-探测漫反射显微成像。光谱学/显微镜方法可以可视化和关联微观组成和电子变化（即，陷阱状态）在真实的空间中的时间分辨物理学。在TAM图像中的异质结模式显示，一些晶粒表现出正的激发态吸收（ESA）信号，而其他人则表现出负的基态漂白（GSB）。我们的研究结果可视化，薄膜处理，如空气退火和Na此外，有一个明确的影响激发态图案的异质性。重要的是，我们报告稳定的电荷载流子超过100 ps。我们应用图像主成分和直方图的TAM图像的定量分析，去卷积和可视化的贡献和指纹的少数自由载流子和子带隙陷阱载流子。
Earth-abundant Cu2BaSnS4-xSex(CBTSSe) represents a recent alternative for Cu2ZnSn(S,Se)4for solar energy conversion with a lower level of disorder and band tailing. We report the heterogeneous excited-state and trap-state pattern in different solution-processed CBTSSe films using ultrafast two-color pump-probe diffuse reflectance microscopic imaging. The spectroscopy/microscopy method can visualize and correlate the microscopic compositional and electronic variations (i.e., trap states) in real space with time-resolved photophysics. Heterogeneity patterns in TAM images show that some grains exhibit a positive excited-state absorption (ESA) signal, while others show negative ground-state bleaching (GSB). Our results visualize that film processing, such as air annealing and Na addition, has a clear influence on the heterogeneity of the excited-state pattern. Importantly, we report stable charge carrier over 100 ps. We applied the image principal component and histogram for quantitative analysis of TAM images to deconvolute and visualize the contribution and fingerprints of minority free carriers and sub-band-gap trapped carriers.