High efficiency single-junction InGaP photovoltaic devices under low intensity light illumination

The fabricated single junction InGaP photovoltaic devices show an overall 30% conversion efficiency under 1.27 uW/cm
²
illumination. The development not only enables long lifetime radio-isotope based batteries but also, more important for the daily life, has the potential to promote the concept of the internet of things by efficiently powering indoor wireless sensors. To reduce the dark current and increase the absorption at longer wavelengths (>550 nm), several parameters including doping and thickness are optimized for the device design. Additional current-voltage characteristics under dark conditions and external quantum efficiency were also performed in order to evaluate the performance of the InGaP photovoltaic cells.