由 PbCl 衍生的 MAPbI 中从晶态前体到钙钛矿的转变。
Transformation from crystalline precursor to perovskite in PbCl-derived MAPbI.
机构信息
SSRL Materials Science Division, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd MS 69, Menlo Park, California, 94025, USA.
Department of Chemistry, Stanford University, Stanford, California, 94305, USA.
出版信息
Nat Commun. 2018 Aug 27;9(1):3458. doi: 10.1038/s41467-018-05937-4.
Understanding the formation chemistry of metal halide perovskites is key to optimizing processing conditions and realizing enhanced optoelectronic properties. Here, we reveal the structure of the crystalline precursor in the formation of methylammonium lead iodide (MAPbI) from the single-step deposition of lead chloride and three equivalents of methylammonium iodide (PbCl + 3MAI) (MA = CHNH). The as-spun film consists of crystalline MAPbICl, which is composed of one-dimensional chains of lead halide octahedra, coexisting with disordered MACl. We show that the transformation of precursor into perovskite is not favored in the presence of MACl, and thus the gradual evaporation of MACl acts as a self-regulating mechanism to slow the conversion. We propose the stable precursor phase enables dense film coverage and the slow transformation may lead to improved crystal quality. This enhanced chemical understanding is paramount for the rational control of film deposition and the fabrication of superior optoelectronic devices.
了解卤化金属钙钛矿的形成化学是优化处理条件和实现增强光电性能的关键。在这里，我们揭示了从氯化铅和三当量的甲脒碘化（PbCl + 3MAI）（MA = CHNH）的一步沉积形成碘化甲基铵铅（MAPbI）过程中，晶态前体的结构。旋涂的薄膜由结晶的 MAPbICl 组成，它由卤化铅八面体的一维链组成，同时存在无序的 MACl。我们表明，在 MACl 存在的情况下，前体向钙钛矿的转化并不有利，因此 MACl 的逐渐蒸发作为一种自调节机制来减缓转化。我们提出稳定的前体相能够实现致密的薄膜覆盖，而缓慢的转化可能导致晶体质量的提高。这种增强的化学理解对于合理控制薄膜沉积和制造优异的光电设备至关重要。
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