Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA.
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
Nanoscale. 2017 Jan 26;9(4):1475-1483. doi: 10.1039/c6nr08347a.
In this work, we examine the impact of hybrid bimetallic Au/Ag core/shell nanostructures on the carrier dynamics of methylammonium lead tribromide (MAPbBr) mesoporous perovskite solar cells (PSCs). Plasmon-enhanced PSCs incorporated with Au/Ag nanostructures demonstrated improved light harvesting and increased power conversion efficiency by 26% relative to reference devices. Two complementary spectral techniques, transient absorption spectroscopy (TAS) and time-resolved photoluminescence (trPL), were employed to gain a mechanistic understanding of plasmonic enhancement processes. TAS revealed a decrease in the photobleach formation time, which suggests that the nanostructures improve hot carrier thermalization to an equilibrium distribution, relieving hot phonon bottleneck in MAPbBr perovskites. TAS also showed a decrease in carrier decay lifetimes, indicating that nanostructures enhance photoinduced carrier generation and promote efficient electron injection into TiO prior to bulk recombination. Furthermore, nanostructure-incorporated perovskite films demonstrated quenching in steady-state PL and decreases in trPL carrier lifetimes, providing further evidence of improved carrier injection in plasmon-enhanced mesoporous PSCs.
在这项工作中，我们研究了杂化双金属 Au/Ag 核/壳纳米结构对甲脒铅三溴化物（MAPbBr）介孔钙钛矿太阳能电池（PSC）载流子动力学的影响。与参考器件相比，掺入 Au/Ag 纳米结构的等离子体增强型 PSCs 表现出更好的光捕获和 26%的功率转换效率提高。两种互补的光谱技术，瞬态吸收光谱（TAS）和时间分辨光致发光（trPL），被用来深入了解等离子体增强过程。TAS 揭示了光漂白形成时间的减少，这表明纳米结构改善了热载流子热化到平衡分布，缓解了 MAPbBr 钙钛矿中的热声子瓶颈。TAS 还显示出载流子衰减寿命的减少，这表明纳米结构增强了光致载流子的产生，并促进了在体复合之前将电子有效注入 TiO。此外，掺入纳米结构的钙钛矿薄膜在稳态 PL 中表现出猝灭，trPL 载流子寿命减少，进一步证明了等离子体增强介孔 PSC 中载流子注入的改善。
