How pressure change the world of perovskite solar cells - Dr. Xujie Lü

SEPTEMBER 29, 2017

Pressure, as a fundamental thermodynamic parameter that can tailor physical and chemical properties of functional materials, has recently been used in tuning structures and properties of organic-inorganic hybrid perovskites. In recent issue of Chemical Science, a team of scientists led by Dr. Xujie Lü of HPSTAR gave a perspective of how pressure make changes in the hybrid perovskites.

Organic-inorganic hybrid perovskite - a new type of energy material which has recently been found to make highly efficient solar cells that could potentially be commercialized with low cost. In the past several years, their efficiency of converting solar energy into electricity has been improved over 22%.

Pressure has played a key role in alternating various properties of hybrid perovskites in the last a few years. Dr. Xujie Lü and co-workers including Dr. Wenge Yang from HPSTAR gave a comprehensive review on how pressure made changes in this field in their recent Chemical Science paper.

The authors reviewed the recent progress of high-pressure research on hybrid perovskites, including pressure induced lattice and electronic structure changes, pressure induced optical and electrical property variations and summarized their common features and different behaviors, as well as possible reasons for the differences in structure and property changes caused by pressure treatment. Particularly, they described the pressure-induced novel phenomena and pressure-enhanced properties.

They also discussed the underling mechanisms of pressure effects on structure and property evolution. Finally, they gave an outlook on future high-pressure research on hybrid perovskites. The authors advise using chemical pressures and/or interfacial engineering to keep the pressure-induced enhanced properties for practical applications.

“Despite pressure has made intriguing findings in hybrid perovskite research, challenges still exist”, said by Dr. Lü. So a set of improved experimental methods and suitable calculations will be necessary.

作为一种重要的钙钛矿材料，有机-无机杂化钙钛矿（organic-inorganic hybrid perovskite）由于其在光伏应用中高的能量转换效率和低的制备成本，在太阳能电池领域显示出巨大的应用潜力。在短短的几年时间内，有机-无机杂化钙钛矿太阳能电池的光电转化效率已经超过22%，接近硅基太阳能电池的效率。然而，稳定性问题以及对其结构-性能关系理解的不足成为进一步发展的主要障碍。

压力作为一种基础的热力学维度参数，是重要的材料调控手段。通过改变压力可以有效调节材料的电子和晶体结构从而调控材料的物理性质，进而影响其功能和应用。不同于化学掺杂，压力在对材料施加作用时不引入其他影响因素，因此被认为是一种“清洁”的调控手段，从而可以更好的揭示材料的结构性能关系。近几年的研究发现压力可以有效调控杂化钙钛矿材料的结构和性质。近日，北京高压科学研究中心的杨文革和吕旭杰研究员等在 Chemical Science 上发表题为 “Pressure-induced dramatic changes in organic–inorganic halide perovskites”的综述。在这篇综述中，作者主要回顾了近五年来压力对有机无机杂化钙钛矿的结构，光电性能的改变，讨论了潜在的物理机制，并提出高性能钙钛矿光电功能材料的发展提供新的视角。最后对压力及相关技术方法在未来有机无机杂化钙钛矿的研究发展中可能扮演的角色做了展望，例如通过引入化学压力和界面工程等方法来模拟外加高压电额效果，从而实现杂化钙钛矿的优化改性。