Efficient Hot Hole Extraction in Halide Perovskite/2D Semiconductor van der Waals Heterostructures

Abstract Hot carrier photovoltaics have offered a promising solution to overcome the efficiency bottleneck known as Shockley‐Queisser limit. However, the development of hot carrier photovoltaics lags far behind the conventional ones, one of the long‐standing challenges is how to efficiently extract hot carriers. Here, a hot‐hole extraction efficiency is demonstrated up to 91% in CsPbI 3 /WSe 2 van der Waals heterostructures at carrier densities comparable to the continuous solar excitation. In the CsPbI 3 /WSe 2 heterostructure, the epitaxial CsPbI 3 perovskite with reduced disorders functions as a hot carrier chromophore with an extended relaxation time, monolayer WSe 2 with a unique band nesting structure serves as energy selective contact, the resonant high‐lying energy‐level matching at the ultraclean hetero‐interface with large orbit overlap provides energetically aligned transport channels for efficiently delivering hot holes. The observations also reveal that the resonant high‐lying state accessibility at the hetero‐interface plays a key role in the efficient extraction of hot carriers. The findings provide a design principle toward tailoring out‐of‐equilibrium carrier dynamics for designing hot‐carrier‐driven optoelectronics.