Among the many materials investigated for next-generation photovoltaic cells, organic–inorganic lead halide perovskites have demonstrated great potential thanks to their high power conversion efficiency and solution processability. Within a short period of about 5 years, the efficiency of solar cells based on these materials has increased dramatically from 3.8 to over 20%. Despite the tremendous progress in device performance, much less is known about the underlying photophysics involving charge–orbital–lattice interactions and the role of the organic molecules in this hybrid material remains poorly understood. Here, we report a giant photostrictive response, that is, light-induced lattice change, of >1,200 p.p.m. in methylammonium lead iodide, which could be the key to understand its superior optical properties. The strong photon-lattice coupling also opens up the possibility of employing these materials in wireless opto-mechanical devices.

Nature Communications 7, Article number: 11193 doi:10.1038/ncomms11193

http://www.nature.com/ncomms/2016/160405/ncomms11193/full/ncomms11193.html

有机-无机卤化铅钙钛矿材料，因其高的能量转化效率和可溶液加工性，被视为是下一代太阳能电池的候选材料。短短5年间，钙钛矿太阳能电池的能量转化效率从3.8%迅猛增长到20%。不过，尽管器件性能上有很大进步，但是科学家对其光物理机理的认识，以及有机分子在材料中的作用还知之甚少。Zhou等人发现，在钙钛矿材料中，存在一种光诱导晶格变化效应，这可能是弄清楚这类材料优异光学性质的关键。（Nature Communications DOI:10.1038/ncomms11193）（新材料在线）