Photoelectrochemistry at semiconductor/liquid interfaces triggered by electrochemiluminescence

Abstract

Summary: The photoelectrochemical charge-transfer process occurring at semiconductor surfaces has important implications in the fields of solar fuels and biodetection. Usually, physical light sources located outside the liquid phase, such as a solar simulator, a light-emitting diode (LED), or a laser, are used for photoelectrochemical studies. Here, we report inducing photoelectrochemistry using an electrochemical source of light, that is, the electrochemiluminescence (ECL) emitted by a model co-reactant system. Results reveal that the ECL illumination can activate several semiconductor (SC) photoelectrodes based on n-type Si, n-type GaAs, and p-type Si. We demonstrate that this emitter-receiver concept, based on dual-light conversion, enables photoelectrochemical charge transfer at the solid/liquid interface, which correlates with the ECL intensity. The singularities of this concept lie in the fact that light emission and collection both occur in the liquid phase, that ECL is an easily miniaturizable photon source, and that the SC/liquid junction can be easily implemented. This approach may open perspectives for remote ECL detection strategies and original photoelectrochemical analytical systems.

Keywords

• Photoelectrochemistry
• Electrochemiluminescence
• Semiconductors
• Photoelectrodes
• Silicon