ABSTRACT Metal halide perovskites (MHPs) have intrinsically slow hot carrier (HC) cooling, and by tethering suitable extractors, photoexcited HCs can effectively be harvested. This enables the utilization of excess carrier energy before thermalization which is crucial to surpass the thermodynamic limit of energy conversion efficiency in photovoltaic devices. The HC cooling process can further be slowed down in MHP quantum dots (QDs) due to energy discretization. Here, we demonstrate efficient room‐temperature hot‐hole extraction from CsPbI 3 (CPI) QDs, a narrow bandgap MHP composition, to energetically favourable 5,10,15,20‐tetra(4‐pyridyl) porphyrin (TPyP). Steady‐state and time‐resolved photoluminescence studies reveal dynamic photoluminescence quenching which is attributed to the strong binding affinity of the TPyP molecules to the CPI QD surface. Employing transient absorption spectroscopy ( fs ‐TAS), we show that there is a significant lowering of the hot‐hole cooling time of these QDs from ∼900 to ∼700 fs in the presence of TPyP, and the average hot‐hole extraction efficiency was estimated to be ∼22%. Further, we demonstrate hot hole extraction in electronically coupled CPI QD solid films to a TPyP layer with an efficiency of ∼29%. These results emphasize the need to explore the coupling of PQDs and macrocyclic molecules to harness photoexcited HCs, which can potentially help in designing next‐generation photovoltaic devices.
Wadepalli et al. (Mon,) studied this question.