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Updated: Dec 30, 2025
Hyperspectral Imaging as a Tool to Study Optical Anisotropy in Lanthanide-Based Molecular Single Crystals
Published on: April 14, 2020
Anisotropy of Excitons in Two-Dimensional Perovskite Crystals
Junze Li1, Jiaqi Ma1, Xue Cheng2
1School of Optical and Electronic Information , Huazhong University of Science and Technology , Wuhan 430074 , China.
Abstract:
Two-dimensional (2D) perovskites show great potential for optoelectronic applications due to their bandgap tunability, extremely large excition binding energy, and large crystal anisotropy compared with their three-dimensional counterparts. To fully explore exciton-based applications and improve their performance, it is essential to understand the exciton behavior in 2D perovskites. Here, we investigate exciton anisotropy within the crystallographic plane and cross plane of (C4H9NH3)2PbI4 2D perovskite crystals by polarization-resolved photoluminescence, reflection, and photoconductivity studies. We observe a polarization-dependent emission evolution and an enhanced self-trapped exciton emission with an oblique incident excitation from the cross plane. Furthermore, the anisotropy of excitons in (C4H9NH3)2PbI4 2D perovskite crystals is identified by polarization-resolved photoluminescence and photoconductivity measurement, and a completely opposite polarization-dependent behavior was observed for free excitons and self-trapped excitons. We attribute this different anisotropy to the existence of out-of-plane excitons and different optical selection rule for free excitons and self-trapped excitons. Our findings will shed light on designing and improving the performance of exciton-based optoelectronic devices in 2D perovskites.
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