Photosensitization of Single-Crystal ZnO by a Conjugated Polyelectrolyte Designed to Avoid Aggregation

A conjugated polyelectrolyte (CPE) based on a poly(phenylene ethynylene) backbone designed to avoid interchain aggregation was adsorbed onto n-type zinc oxide (0001) single crystals. Photophysical, atomic force microscopy, and photoelectrochemical measurements confirm the absence of aggregation in solution and on ZnO single-crystal surfaces. At high surface coverage on the ZnO surface, individual polymer chains are resolved, and photocurrent efficiency measurements suggest that charge injection occurs with modest efficiency.