USING SURFACE PHOTOVOLTAGE SPECTROSCOPY AND PHOTOELECTROCHEMISTRY TO STUDY THE ELECTRONIC PROPERTIES OF SEMICONDUCTOR NANOCRYSTALS UNDER LIGHT EXCITATION FOR SOLAR WATER SPLITTING APPLICATIONS

摘要

We have applied photoelectrochemical measurements to investigate the size dependent absolute positions of the conduction band edge in CdSe quantum dots and were able to correlate the observed trend with their variable photocatalytic hydrogen evolution activity. At the same time, SPV measurements demonstrated a size dependency of the onset photon energy for charge separation across the QD-substrate interface. Interestingly, the charge injection type changed from electrons for the larger dots to holes for the smaller ones. Ultimately, the understanding the relationship between QD size, energetics and charge transfer kinetics will determine our ability to optimize solar energy to fuel conversion with semiconductor nanomaterials.