New solar cells mimic natural photosynthesis

Abstract

A new type of solar cell shows promise not only for generating electricity but also for producing chemicals. The device, being developed by H. Ti Tien and coworkers at Michigan State University, depends on a process reminiscent of natural photosynthesis. Tien, a professor of physiology and biophysics at Michigan State, notes that solid-state solar cells are expensive because they require highly purified single crystals. A less expensive alternative is to use semiconducting polycrystallites in photoelectrochemical cells (PEC). A conventional PEC consists of a photoelectrode made of semiconducting material, a counterelectrode, and an electrolyte, all contained in one compartment. Efficient PECs have been made using that approach. However, Tien says, the single-compartment design precludes the separation of light-generated products. The new approach, modeled on photosynthesis, overcomes that drawback. In green plant photosynthesis, a pigmented bilayer lipid membrane separates two aqueous phases. Quanta of vi...