Park Yujin, Choi Jungkweon, Lee Changhwan, Cho An-Na, Cho Dae Won, Park Nam-Gyu, Ihee Hyotcherl, Park Jeong Young
Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701 , Republic of Korea.
Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 305-701 , Republic of Korea.
Nano Lett. 2019 Aug 14;19(8):5489-5495. doi: 10.1021/acs.nanolett.9b02009. Epub 2019 Jul 31.
A fundamental understanding of hot electron transport is critical for developing efficient hot-carrier-based solar cells. There have been significant efforts to enhance hot electron flux, and it has been found that a key factor affecting the hot electron flux is the lifetime of the hot electrons. Here, we report a combined study of hot electron flux and the lifetime of hot carriers using a perovskite-modified plasmonic nanodiode. We found that perovskite deposition on a plasmonic nanodiode can considerably improve hot electron generation induced by photon absorption. The perovskite plasmonic nanodiode consists of MAPbI layers covering a plasmonic-Au/TiO Schottky junction that is composed of randomly connected Au nanoislands deposited on a TiO layer. The measured incident photon-to-electron conversion efficiency and the short-circuit photocurrent show a significantly improved solar-to-electrical conversion performance of this nanodiode. Such an improvement is ascribed to the improved hot electron flux in MAPbI caused by effective light absorption from near-field enhancement of plasmonic Au and the efficient capture of hot electrons from Au nanoislands via the formation of a three-dimensional Schottky interface. The relation between the lifetime and flux of hot electrons was confirmed by femtosecond transient absorption spectroscopy that showed considerably longer hot electron lifetimes in MAPbI combined with the plasmonic Au structure. These findings can provide a fundamental understanding of hot electron generation and transport in perovskite, which can provide helpful guidance to designing efficient hot carrier photovoltaics.
对热电子输运的基本理解对于开发高效的基于热载流子的太阳能电池至关重要。人们已经做出了巨大努力来提高热电子通量，并且已经发现影响热电子通量的一个关键因素是热电子的寿命。在这里，我们报告了一项使用钙钛矿修饰的等离子体纳米二极管对热电子通量和热载流子寿命的联合研究。我们发现钙钛矿沉积在等离子体纳米二极管上可以显著改善由光子吸收诱导的热电子产生。钙钛矿等离子体纳米二极管由覆盖在等离子体 - Au/TiO肖特基结上的MAPbI层组成，该肖特基结由沉积在TiO层上的随机连接的Au纳米岛构成。测量的入射光子到电子转换效率和短路光电流显示出该纳米二极管的太阳能到电能转换性能有显著提高。这种改进归因于由于等离子体Au的近场增强导致的有效光吸收以及通过形成三维肖特基界面从Au纳米岛有效捕获热电子而使MAPbI中的热电子通量得到改善。飞秒瞬态吸收光谱证实了热电子寿命与通量之间的关系，该光谱显示在与等离子体Au结构结合的MAPbI中热电子寿命长得多。这些发现可以为钙钛矿中热电子的产生和输运提供基本理解，这可以为设计高效的热载流子光伏器件提供有益的指导。
