Neutral-color Semi-transparent Crystalline Silicon Solar Cells

Semi-transparent solar cells are an attractive energy conversion device, because it can be used in various applications in our daily life such as building-integrated photovoltaics (BIPV), and vehicle-integrated photovoltaics (VIPV). In this study, we propose neutral-color semi-transparent solar cells using crystalline silicon (c-Si) which is known to be opaque. Novel semi-transparent c-Si substrates were fabricated by applying micro-hole arrays in a bare c-Si wafer. In this semi-transparent substrate, a light transmitting area was designed to enable all incident visible light to be transmitted through the substrate, in order to achieve a colorless substrate, while a light absorption area was designed to efficiently absorb the incident light in the spectral range between 300 nm to 1100 nm by using the substrate with more than 150 ??m thickness. With optimized micro-hole arrays, our 1 cm2 neutral-color semitransparent c-Si solar cells exhibit a power conversion efficiency of up to 11.4%, with Jsc = 29.4 mA/cm2; Voc = 588 mV; and FF = 66.0% with a transmittance of 20 %. To the best of our knowledge, this is the record efficiency for all kinds of semi-transparent solar cells. Hence, our novel c-Si semi-transparent solar cells based on micro-hole arrays presents a unique opportunity to develop next-generation colorless semi-transparent solar cells which would satisfy high efficiency as well as high stability