光致发光
带隙
钙钛矿(结构)
激子
单晶
材料科学
光电子学
光学
结晶学
Crystal(编程语言)
凝聚态物理
化学
物理
计算机科学
程序设计语言
作者
Tariq Sheikh,Aparna Shinde,Shailaja Mahamuni,Angshuman Nag
出处
期刊:ACS energy letters
[American Chemical Society]
日期:2018-11-09
卷期号:3 (12): 2940-2946
被引量:109
标识
DOI:10.1021/acsenergylett.8b01799
摘要
Optoelectronic devices of 2D layered Pb-halide perovskites depend on light absorption/emission, exciton dissociation/transfer, and charge transfer processes, which in turn depend on bandgap and band edges. Here, we report that the surface/subsurface region of 2D (C4H9NH3)2PbI4 perovskite single crystals have a wider bandgap compared to the interior of the crystal. Consequently, single crystals exhibit dual excitonic emission peaks at 2.38 and 2.20 eV arising from the surface and interior, respectively. In contrast, exfoliated layers of (C4H9NH3)2PbI4 exhibit single photoluminescence peak at 2.38 eV, similar to the surface/subsurface of single crystals. Temperature-dependent (300–10 K) photoluminescence and single-crystal diffraction suggest that the overall structure–bandgap relationships are similar for both single-crystal and few-layer samples, but with some difference in phase transition hysteresis. Similar minor structural differences between the bulk (interior) and surface/subsurface of (C4H9NH3)2PbI4 single crystals are the probable cause of the dual bandgap. Single crystals of other layered perovskite systems, namely, (C6H13NH3)2PbI4 and (C4H9NH3)2PbBr4, also exhibit a similar dual bandgap.
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