Infrared-pump electronic-probe of methylammonium lead iodide reveals electronically decoupled organic and inorganic sublattices
Infrared-pump electronic-probe of methylammonium lead iodide reveals electronically decoupled organic and inorganic sublattices
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DOI：
10.1038/s41467-019-08363-2
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发表时间：
2019-01-29
影响因子：
16.6
通讯作者：
Schaller, Richard D.
中科院分区：
文献类型：
--
作者：
Guo, Peijun;Mannodi-Kanakkithodi, Arun;Schaller, Richard D.
有机-无机混合钙钛矿，如甲基铵碘化铅（CH 3 NH3 PbI 3）是改变游戏规则的半导体太阳能电池和发光器件，由于其缺陷容限和特别长的载流子寿命和扩散长度。确定具有大偶极矩的动态无序有机阳离子是否有利于CH 3 NH3 PbI 3的光电性能一直是一个突出的挑战。在此，通过瞬态吸收测量采用红外泵浦脉冲调谐到甲铵振动，我们观察到缓慢的，纳秒长的热耗散从选择性激发的有机模式的无机亚晶格。在热非平衡期间，当诱导的热运动主要集中在有机亚晶格上时，由此产生的瞬态电子特征表明，除了热效应之外，有机阳离子的诱导原子运动不会改变CH 3 NH3 PbI 3的吸收或光致发光响应。结果表明，CH_3NH_3PbI_3的光电性质主要来源于无机铅卤化物骨架.
Organic-inorganic hybrid perovskites such as methylammonium lead iodide (CH3NH3PbI3) are game-changing semiconductors for solar cells and light-emitting devices owing to their defect tolerance and exceptionally long carrier lifetimes and diffusion lengths. Determining whether the dynamically disordered organic cations with large dipole moment benefit the optoelectronic properties of CH3NH3PbI3 has been an outstanding challenge. Herein, via transient absorption measurements employing an infrared pump pulse tuned to a methylammonium vibration, we observe slow, nanosecond-long thermal dissipation from the selectively excited organic mode to the inorganic sublattice. The resulting transient electronic signatures, during the period of thermal-nonequilibrium when the induced thermal motions are mostly concentrated on the organic sublattice, reveal that the induced atomic motions of the organic cations do not alter the absorption or the photoluminescence response of CH3NH3PbI3, beyond thermal effects. Our results suggest that the attractive optoelectronic properties of CH3NH3PbI3 mainly derive from the inorganic lead-halide framework.