Ultrathin a‐Si:H/Oxide Transparent Solar Cells Exhibiting UV‐Blue Selective‐Like Absorption

Abstract

Herein, the fabrication of transparent solar cells based on nanometric (8 and 30 nm) intrinsic hydrogenated amorphous silicon films (a‐Si:H) and using oxide thin films as transparent carrier selective contacts are reported. The ultrathin devices present photovoltaic effect and high average visible transmittance (AVT). Additionally, they display a shifted spectral response toward short wavelengths. Glass/fluorine‐doped tin oxide (FTO)/aluminum‐doped zinc oxide (AZO)/a‐Si:H/MoO3/indium tin oxide (ITO) prototypes are shown, presenting AVT = 35% and photovoltaic conversion efficiency (PCE) = 2% for a device with a 30 nm a‐Si:H film. This yields a light utilization efficiency (LUE) of 0.7%, a record up to this date for inorganic oxide‐based transparent solar cells. For devices including an 8 nm a‐Si:H film, the AVT reaches 66% with a PCE = 0.6% (LUE = 0.4%). These high AVT values are comparable or even superior in some cases to those achieved for pure oxide devices. These findings confirm the potential of the proposed architectures for the development of highly transparent energy harvesters as functional components in building‐integrated photovoltaics (BIPV), agrophotovoltaics (APV), sensors and other low‐power devices. In addition, these devices are fabricated with earth‐abundant materials and with up‐scalable techniques that can allow for a feasible implementation.