ACS Nano 12, 2893–2899 (2018)

Solar cells suffer from reduced performance on cloudy days, leading to intermittent energy supply in all but the sunniest of locations. This poses a challenge to the expansion of the solar sector. To improve power generation in cloudy areas there have been attempts to integrate solar cells with triboelectric nanogenerators (TENGs) that harvest power from raindrops. Integration has proved difficult in practice, however, because the TENG device — which sits above the solar cell — intercepts sunlight, reducing solar cell performance to an unacceptable degree.

Credit: Ken Welsh / Alamy Stock Photo

Yuqiang Liu and Na Sun from Soochow University, China, and colleagues solved this problem by using a mutual function electrode film layer for the solar and TENG components. This integrated system is able to convert solar and raindrop energy into electrical power without significant antagonism between the two components, combining the advantages of the high current output level of the solar cell and the high voltage output level of the TENG. This innovation provides a means to collect energy from the environment under different weather conditions and may in due course find application in wet regions that are less suited to conventional solar arrays.