Wei Qi, Yin Jun, Bakr Osman M, Wang Ze, Wang Chenhao, Mohammed Omar F, Li Mingjie, Xing Guichuan
Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR, 999078, China.
Division of Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
Angew Chem Int Ed Engl. 2021 May 3;60(19):10957-10963. doi: 10.1002/anie.202100099. Epub 2021 Mar 30.
The fast hot-carrier cooling process in the solar-absorbers fundamentally limits their photon-conversion efficiencies. It is highly desirable to develop a solar absorber with long-lived hot-carriers at sun-illumination intensity, 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 cm is found to be ≈3 times smaller than that of un-doped perovskites for T=500 K hot carriers, and up to ten times when the hot-carrier temperature approaches 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 processes. Our findings present a practical strategy to slow down the hot-carrier cooling in perovskites at low carrier densities, which would be invaluable for the further development of practical hot-carrier photovoltaics based on perovskites.
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它们的光子转换效率。迫切需要开发一种在阳光照射强度下具有长寿命热载流子的太阳能吸收器，可用于开发效率更高的热载流子太阳能电池。在此，我们通过瞬态吸收光谱测量和理论计算揭示，与原始样品相比，锌掺杂（0.34%）的卤化物钙钛矿具有较慢的热载流子冷却速度。对于T = 500K的热载流子，在10 cm的低光激发水平下，热载流子能量损失率比未掺杂的钙钛矿小约3倍，当热载流子温度接近晶格温度时，该损失率高达未掺杂钙钛矿的十倍。将锌掺杂剂引入钙钛矿可以减少导带之间的非绝热耦合，从而延缓光生热载流子的弛豫过程。我们的研究结果提出了一种在低载流子密度下减缓钙钛矿中热载流子冷却的实用策略，这对于基于钙钛矿的实用热载流子光伏技术的进一步发展将具有重要价值。
