Charge injection onto semiconductor surface

Illumination of metal-coated semiconductor particles leads to the accumulation of trapped electrons. Islands of noble metals (Pt, Rh, and Pd) on the surface of particles have higher electron affinity and therefore upon charge pair formation electrons are transferred from the semiconductor particle onto the metal islands. Due to the decreased recombination rate and high electron affinity of noble metals, more than one electron can be stored on metallized particles. Therefore, metal-coated particles can be used for subsequent simultaneous injection of multiple charges, and the reduction of compounds that cannot proceed via a one-electron reduction process. In these processes the crucial parameter that governs charge separation processes is the coupling between semiconductor particles and the metal... 

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