Mandal Arnab, Ghosh Anima, Ghosh Dibyendu, Bhattacharyya Sayan
Department of Chemical Sciences, and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER), Kolkata, Mohanpur-741246, India.
ACS Appl Mater Interfaces. 2021 Sep 15;13(36):43104-43114. doi: 10.1021/acsami.1c13452. Epub 2021 Sep 5.
Chemical transformation of typically "nonlayered" phases into two-dimensional structures remains a formidable task. Among the thickness tunable CsPbX ( = Br, Br/I, I) nanosheets (NSs), CsPbBrI NSs with a thickness of ∼4.9 nm have structural stability superior to ∼6.8 nm CsPbI NSs and better hole mobility than ∼3.7 nm CsPbBr NSs. Moving beyond the much-explored CsPbBr photodetectors, we demonstrate a sharp improvement of the photodetection of CsPbBrI NS devices by thickening the NSs to ∼6.1 nm through combining 8-carbon and 18-carbon ligand surfactants. Thereby, the responsivity increases up to one of the highest values of 3313 A W at 1.5 V (and 3946 A W at 2 V) with detectivity of 1.6 × 10 Jones at 1.5 V, due to the increase in carrier mobility up to 7.9 × 10 cm V s. The better device performance of the NSs than 8.6-13.9 nm nanocubes (NCs) is due to their planarity which facilitates in-plane mobilization of the charge carriers.
将典型的“非层状”相化学转化为二维结构仍然是一项艰巨的任务。在厚度可调的CsPbX（X = Br、Br/I、I）纳米片（NSs）中，厚度约为4.9 nm的CsPbBrI NSs具有优于约6.8 nm的CsPbI NSs的结构稳定性，且空穴迁移率比约3.7 nm的CsPbBr NSs更好。除了已被广泛研究的CsPbBr光电探测器，我们通过将8碳和18碳配体表面活性剂结合，将NSs增厚至约6.1 nm，展示了CsPbBrI NS器件光探测性能的显著提升。因此，由于载流子迁移率提高到7.9×10⁻³ cm² V⁻¹ s⁻¹，在1.5 V时响应度提高到3313 A W⁻¹（在2 V时为3946 A W⁻¹）的最高值之一，在1.5 V时探测率为1.6×10¹³ Jones。NSs比8.6 - 13.9 nm的纳米立方体（NCs）具有更好的器件性能，这归因于它们的平面性，有利于电荷载流子的面内移动。
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