Photoelectric Conversion Based on Proton-Coupled Electron Transfer Reactions

2014-06-04T00:00:00Z (GMT) by Xiaojiang Xie Eric Bakker
Making efficient use of solar energy is one of the biggest challenges of our time. In nature, solar energy can be harvested by photosynthesis where proton-coupled electron transfer (PCET) plays a critical role. Here, PCET is utilized for the first time to directly convert light energy to electrical energy. Quinone/hydroquinone PCET redox couples were used to produce a photovoltage along with spiropyrans, photoswitchable compounds that undergo reversible transformation between a ring-closed (Sp) and ring-opened form (Mc). The Mc form is more basic than the Sp form, and the open-circuit voltage (<i>V</i><sub>oc</sub>) is related to the proton concentration and that of the Sp/Mc ratio controlled by light. <i>V</i><sub>oc</sub> values from 100 to 140 mV were produced. In addition to direct current (<i>J</i><sub>sc</sub> ca. 9 μA cm<sup>–2</sup>), alternating current in the range of 0.1 to 200 Hz was also produced by manipulating the input light.