Influence of pH solution on photoluminescence of porous silicon

The radiative lifetime of as-prepared and modified layers of porous silicon (por-Si) were studied in liquid solutions with different pH. It was observed that por-Si photoluminescence (PL) intensity and decay lifetime strongly depend on pH value. This phenomenon is explained by competition of the following processes: UV-induced hydrogen effusion, hydrogen adsorption from the buffer solution, and por-Si oxidation. Regarding the phenomenon a pH change sensor can be proposed. Por-Si layer degradation can be decreased somehow by protective PEDOT layer.