澳门大学邢贵川团队揭示了锌掺杂对卤化物钙钛矿热载流子冷却速率的影响。相关研究成果发表在2021年2月25日出版的《德国应用化学》。

太阳能吸收器中的快速热载流子冷却过程从根本上限制了光子能量转换效率。在太阳光照水平下开发具有长寿命热载流子的太阳能吸收器是非常有必要的，它可以用来开发效率更高的热载流子太阳能电池。

该文中，研究人员通过瞬态吸收光谱测量和理论计算发现，与原始样品相比，掺锌（0.34%）卤化物钙钛矿具有较慢的热载流子冷却。对于500 K热载流子，在1017cm^‐3的低光激发水平下，热载流子能量损失率比未掺杂钙钛矿小约3倍，当热载流子温度接近晶格温度时，热载流子能量损失率高达10倍。在钙钛矿中掺入锌可以减少导带间的非绝热耦合，从而延缓光生热载流子弛豫过程。

该发现提供了一种在低载流子密度下减缓钙钛矿热载流子冷却的实用策略，这对钙钛矿热载流子光伏的进一步发展具有重要的参考价值。

附：英文原文

Title: Effect of Zinc‐doping on the Reduction of the Hot‐carrier Cooling Rate in Halide Perovskites

Author: Guichuan Xing, Qi WEI, Jun Yin, Osman M. Bakr, Ze Wang, Chenhao Wang, Omar F. Mohammed, Mingjie Li

Issue&Volume: 2021-02-25

Abstract: Fast hot‐carrier cooling process in the solar‐absorbers fundamentally limits the photon‐energy conversion efficiencies. It is highly desirable to develop the solar absorber with long‐lived hot‐carriers at sun‐illumination level, which can be used to develop the hot‐carrier solar cells with enhanced efficiency. Herein, we reveal that zinc‐doped (0.34%) halide perovskites have the slower hot‐carrier cooling compared with the pristine sample through the transient absorption spectroscopy measurements and theoretical calculations. The hot‐carrier energy loss rate at the low photoexcitation level of 10  17  cm  ‐3  is found to be ~3 times smaller than that of un‐doped perovskites for 500‐K hot carriers, and up to ten times when the hot‐carrier temperature approaching the lattice temperature. The incorporation of zinc‐dopant into perovskites can reduce the nonadiabatic couplings between conduction bands, which retards the photogenerated hot‐carriers relaxation process. Our findings present a practical strategy to slow down the hot‐carrier cooling in perovskites at low carrier densities, which are valuable for the further development of practical perovskite hot‐carrier photovoltaics  .

DOI: 10.1002/anie.202100099

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202100099