Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, NC 27599, USA.
Department of Mechanical and Materials Engineering and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
Science. 2020 Mar 20;367(6484):1352-1358. doi: 10.1126/science.aba0893.
We report the profiling of spatial and energetic distributions of trap states in metal halide perovskite single-crystalline and polycrystalline solar cells. The trap densities in single crystals varied by five orders of magnitude, with a lowest value of 2 × 10 per cubic centimeter and most of the deep traps located at crystal surfaces. The charge trap densities of all depths of the interfaces of the polycrystalline films were one to two orders of magnitude greater than that of the film interior, and the trap density at the film interior was still two to three orders of magnitude greater than that in high-quality single crystals. Suprisingly, after surface passivation, most deep traps were detected near the interface of perovskites and hole transport layers, where a large density of nanocrystals were embedded, limiting the efficiency of solar cells.
我们报告了在金属卤化物钙钛矿单晶和多晶太阳能电池中，陷阱态的空间和能量分布的剖析。单晶体中的陷阱密度变化了五个数量级，最低值为 2×10 每立方厘米，并且大多数深陷阱位于晶体表面。多晶薄膜界面的所有深度的电荷陷阱密度都比薄膜内部的密度大一个到两个数量级，而薄膜内部的陷阱密度仍然比高质量单晶的密度大两个到三个数量级。令人惊讶的是，经过表面钝化后，大多数深陷阱被检测到在钙钛矿和空穴传输层的界面附近，那里嵌入了大量的纳米晶体，限制了太阳能电池的效率。
