Plasmonic Hot-Carrier-Mediated Solar Energy Conversion and Tunablephotochemical Reactions

Abstract

The detailed balance between photon-absorption and energy loss constrains the efficiency of conventional solar cells to the Shockley-Queisser limit. Recent developments of hot-carrier science and technology have stimulated the design of solar cells utilizing hot-carriers, but the efficiency is limited. In this presentation, a theoretical model for hot-carrier solar cells is discussed. Our theoretical model indicates that this cell can significantly improve the absorption of solar radiation without reducing open-circuit voltage. However, a significant fraction of the hot-carriers have energies below the Schottky barrier, which makes the cell suffer low internal quantum efficiency. Despite the limitation in solar energy conversion, the plasmonic hot-carrier can be applied to drive the photochemistry which is impossible in previous thought. Examples of hot-carrier mediated photochemical reaction and how the plasmonic hot-carriers can be employed to tune the chemical reactions will also be introduced. Our non-adiabatic molecular dynamics simulations and time-dependent density functional calculations found the hot-carriers generated from the nanoparticle can transfer to the anti-bonding state of the attached molecule and drive the photochemical reaction. We also found chemical reaction is tunable if the molecule is placed in the center of the plasmonic dimer. The reaction rate can be either suppressed or enhanced depending on the geometry. Thus, our work demonstrates the possibility of tunable photochemistry via plasmonic hot-carriers.