Towards Systematic Determination of Hot Carrier Metrics in Halide Perovskites

Halide perovskites possess exceptional slow hot carrier cooling properties, making them excellent contenders for use as suitable hot carrier absorbers. The combination of an enhanced phonon bottleneck and Auger heating effects at high carrier densities extends the hot carrier cooling rates into tens of picoseconds. Further manipulation of such effects through quantum confinement in nanocrystals could further lengthen the cooling time, facilitating the sustainment of high carrier temperatures in these materials for their potential use in hot carrier solar cells (HCSCs).<br/><br/>The quantities such as carrier temperature and quasi-Fermi levels are important hot carrier metrics which can aid the development of HCSCs. Thus, their accurate and systematic determination is non-trivial for greater comparability between studies and for rapid screening of potential hot carrier absorber materials. We critically evaluate the commonly adopted procedures for determining these hot carrier metrics in halide perovskites from commonly used spectroscopic methods. We introduce alternative, systematic methods for the unambiguous determination of the relevant hot carrier metrics. Ultimately, we focus on the discussion on how discrepancies between different studies may influence the interpretations of hot carrier cooling processes in halide perovskites and how to circumvent these pitfalls. We also evaluate the potential of hot carriers in next generation solar cells.