Disclosed herein are photoactive compositions that include a semiconductor and plasmon-resonating nanoparticles that are capable of concentrating light at a wavelength that is substantially the same as the wavelength of light necessary to promote an electron from a valance band to a conduction band in the semiconductor. As such, the plasmon-resonating nanoparticles direct light to the band gap of the semiconductor at an increased intensity (relative to when such nanoparticles are not present). And because of that increased intensity, the photoactive composition can be more efficiently used to catalyze a photochemical reaction or generate electrical potential in a photovoltaic cell.
STATEMENT OF GOVERNMENTAL INTEREST
 This invention was made with governmental support under grants from the U.S. Department of Energy, Office of Basic Energy Sciences (DOE-BES) and Division of Chemical Science (FG-02-05ER15686), and the National Science Foundation (CBET0756255). The government has certain rights in the invention.