Matching maximum power point of gaas solar cells for a photo-rechargeable system with >26% overall efficiency

The rapid development of the Internet of Things and portable/wearable electronic devices has posed increasing demands for handy and efficient off-grid powers. Solar self-powered systems are one of the emerging options, yet their performance is generally not satisfactory. Herein, a rationally designed photo-rechargeable system is constructed by combining highly efficient GaAs solar cells with an array of aqueous Zn-I2 microbatteries (MBs). Through judiciously matching the charging platform of MBs with the maximum power point (MPP) of GaAs solar cells via circuit designs, an unprecedented overall conversion efficiency ( •overall) of 26.32% has been achieved. As a proof of concept, the photo-rechargeable system discharges for 1389 seconds in darkness after 1-minute charging under AM 1.5 G, underscoring its potential for the energy supply of future smart devices.