Free Excitons and Exciton-Phonon Coupling in CH3NH3PbI3 Single Crystals Revealed by Photocurrent and Photoluminescence Measurements at Low Temperatures
Free Excitons and Exciton-Phonon Coupling in CH3NH3PbI3 Single Crystals Revealed by Photocurrent and Photoluminescence Measurements at Low Temperatures
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DOI：
10.1021/acs.jpclett.6b02432
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发表时间：
2016-12-01
影响因子：
5.7
通讯作者：
Kanemitsu, Yoshihiko
中科院分区：
文献类型：
--
作者：
Phuong, Le Quang;Nakaike, Yumi;Kanemitsu, Yoshihiko
利用温度相关光电流（PC）和光致发光（PL）光谱研究了CH3NH3PbI3 （MAPbI(3)）单晶中的激子-声子耦合和激子结合能。PC和PL数据提供了正交相MAPbI中激子存在的明确证据(3)。与PL数据相比，温度相关的PC数据受束缚激子的影响较小，因此PC数据反映了激子的本征散射。我们观察到MAPbI(3)中的激子-声子耦合很强，并确定了纵向光学声子能量为16.1 meV。此外，基于PC和PL数据的温度依赖性，我们评估了正交相MAPbI(3)单晶的激子结合能为12.4 meV。我们的发现为同时使用PC和PL测量来精确确定钙钛矿的基本性质铺平了道路。
We investigated the exciton phonon couplings and exciton binding energy in CH3NH3PbI3 (MAPbI(3)) single crystals using temperature-dependent photocurrent (PC) and photoluminescence (PL) spectroscopy. The PC and PL data provide clear evidence of the existence of excitons in orthorhombic-phase MAPbI(3). The temperature-dependent PC data were found to be less influenced by the bound excitons than the PL data, and thus the PC data reflect the intrinsic scatterings of excitons. We observed that the exciton phonon couplings were strong in MAPbI(3) and determined the longitudinal optical phonon energy to be 16.1 meV. Moreover, on the basis of the temperature dependences of the PC and PL data, we evaluated the exciton binding energy to be 12.4 meV for orthorhombic-phase MAPbI(3) single crystals. Our findings pave a way for using simultaneous PC and PL measurements to determine precisely fundamental properties of perovskites.