Scientists in Japan have made the first device that can convert solar energy into electricity and then store the resulting electric charge. The "photocapacitor" designed by Tsutomu Miyasaka and Takurou Murakami at Toin University in Yokohama could be used to power mobile phones and other hand-held devices (Appl. Phys. Lett. 85 3932).
Conventional solar cells need a secondary device, such as a battery, to store the electrical power generated from light. The photocapacitor combines the photoelectric and storage functions in a single structure.
Miyasaka says that the next goal is to increase the charging voltage and the charge-discharge capacity to a practically and industrially useful level for applications.