Hot carriers in halide perovskites

Halide perovskites possessing exemplary optoelectronic properties are excellent solar absorbers for high-efficiency perovskite solar cells that have attained record power conversion efficiencies approaching the theoretical Shockley-Queisser (SQ) limit. The discovery of exceptional slow hot carrier cooling properties in halide perovskites has sparked widespread interest in their potential use in novel photovoltaic concepts such as the hot carrier solar cell and multiple exciton generation solar cell, both of which can achieve efficiencies exceeding the SQ limit. In this chapter, the mechanisms underlying hot carrier cooling and multiple exciton generation in halide perovskites are discussed in detail. Methods for characterizing these processes and obtaining the necessary metrics will also be discussed. We also provide a brief overview of key considerations for the use of hot carriers and multiple exciton generation effects in practical next-generation photovoltaic devices capable of exceeding the encroaching SQ limit.