Flannery Laura, Garden Kelsey, Berzansky Alex, Zhang Xueqiao, Labram John G, Whittaker-Brooks Luisa
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States.
School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, Oregon 97331, United States.
ACS Omega. 2025 May 12;10(20):20536-20549. doi: 10.1021/acsomega.5c01182. eCollection 2025 May 27.
Understanding the interplay between crystal engineering and the coupled electronic-ionic charge transport properties of metal halide perovskites remains a critical issue in the field. In this work, we developed an experimental approach to tune the crystallite orientation of methylammonium lead iodide (CHNHPbI) while maintaining their overall crystal structure. This approach allows us to selectively manipulate crystallite orientations to control out-of-plane ion migration and mitigate voltage bias stress effects in CHNHPbI thin films. By employing advanced diffraction and spectroscopic techniques, we achieved a comprehensive characterization of the anisotropic crystallite properties in CHNHPbI thin films with distinct preferred orientations. Our findings reveal that specific crystallite orientations, particularly those that limit halide ion migration pathways along the (200) crystallographic plane, significantly suppress out-of-plane ion migration. This suppression reduces hysteresis and alleviates voltage bias stress effects in CHNHPbI solar cells, ultimately enhancing device stability and performance. These insights not only deepen our understanding of the relationship between crystallite orientation and device functionality but also highlight a promising strategy for regulating ion migration in MHP-based devices. This approach holds significant potential for advancing the stability and efficiency of perovskite solar cells and extending its applicability to other optoelectronic devices.
理解晶体工程与金属卤化物钙钛矿的耦合电子 - 离子电荷传输特性之间的相互作用仍然是该领域的一个关键问题。在这项工作中，我们开发了一种实验方法，在保持甲基碘化铅（CH₃NH₃PbI₃）整体晶体结构的同时调整其微晶取向。这种方法使我们能够选择性地控制微晶取向，以控制CH₃NH₃PbI₃薄膜中的面外离子迁移并减轻电压偏置应力效应。通过采用先进的衍射和光谱技术，我们对具有不同择优取向的CH₃NH₃PbI₃薄膜中的各向异性微晶特性进行了全面表征。我们的研究结果表明，特定的微晶取向，特别是那些限制卤离子沿（200）晶面迁移路径的取向，能显著抑制面外离子迁移。这种抑制减少了滞后现象，并减轻了CH₃NH₃PbI₃太阳能电池中的电压偏置应力效应，最终提高了器件的稳定性和性能。这些见解不仅加深了我们对微晶取向与器件功能之间关系的理解，还突出了一种在基于MHP的器件中调节离子迁移的有前景的策略。这种方法在提高钙钛矿太阳能电池的稳定性和效率以及将其应用扩展到其他光电器件方面具有巨大潜力。
