Hot-carrier photocatalysts with energy-selective contacts based on quantum wells and dots

Abstract

Two types of hot-carrier photocatalysts (HCPCs) based on quantum well and quantum dot energy-selective contacts (ESCs) have been proposed. The transport equations for both types of devices are derived using the ballistic transport theory. The electrocatalytic behavior of reaction sites in water splitting is modeled by using the Butler–Volmer equation. The impacts of the ESC parameters, including the extraction energy level and the transmission energy width, on the performance of HCPC devices have been investigated. The results indicate that the thermal losses from non-ideal ESCs significantly limit HCPC efficiency, which can be enhanced by optimizing ESC parameters. Comparisons show that HCPCs with quantum dot ESCs outperform those with quantum well ESCs, owing to their superior carrier transport capability and lower thermal loss rates. For an absorber bandgap of 1 eV, the optimized solar-to-H2 energy conversion efficiencies of the two HCPCs reach 62.34% and 64.93%, respectively, highlighting the promising application potential of these catalysts.