Cool carriers: triplet diffusion dominates upconversion yield
Cool carriers: triplet diffusion dominates upconversion yield
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冷载流子：三线态扩散主导上转换产率
DOI：
10.1039/d3nr04446g
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发表时间：
2023
期刊：
影响因子：
6.7
通讯作者：
Nienhaus, Lea
中科院分区：
文献类型：
--
作者：
Sullivan, Colette M.;Kuszynski, Jason E.;Kovalev, Alexey;Siegrist, Theo;Schaller, Richard D.;Strouse, Geoffrey F.;Nienhaus, Lea
钙钛矿作为光致发光中的活性材料和作为固态三重态-三重态湮灭上转换（TTA-UC）的体三重态敏化剂两者都得到了普及。在广泛应用于商业光伏之前，需要深入了解环境对设备性能的影响。为此，TTA-UC内的甲基铵甲脒三碘化铅（MAFA）/红荧烯UC设备的温度依赖性的结构-功能特性进行了探索。一个强大的温度依赖性的基础UC动力学观察，其中最大UC效率是在170 K，反映了三重态扩散长度，扩散速率和三重态-三重态相遇事件之间的竞争。光谱和结构方法以及理论建模的组合表明，尽管在低温下钙钛矿的载流子寿命显著增加，但TTA-UC动力学不受底层敏化剂性质的影响，而是受底层三重态扩散的限制。
Perovskites have gained popularity both as the active material in photovoltaics and as bulk triplet sensitizers for solid-state triplet–triplet annihilation upconversion (TTA-UC). Prior to widespread implementation into commercial photovoltaics, an in-depth understanding of the environmental influences on device performance is required. To this point, the temperature-dependent structure–function properties of TTA-UC within methylammonium formamidinium lead triiodide (MAFA)/rubrene UC devices are explored. A strong temperature dependence of the underlying UC dynamics is observed, where the maximum UC efficiency is achieved at 170 K, reflecting the competition between triplet diffusion length, diffusion rate, and triplet–triplet encounter events. A combination of spectroscopic and structural methods and theoretical modelling illustrates that despite the significantly increased carrier lifetime of the perovskite at low temperatures, the TTA-UC dynamics are not governed by the underlying sensitizer properties but rather limited by the underlying triplet diffusion.