Single-junction bifacial and semitransparent Sb₂(S,Se)₃ solar cells

Sb-2(S,Se)(3) has become a promising new photovoltaic (PV) material for not only high absorption coefficient, adjustable bandgap but non-toxic, eco-friendly and earth-abundant composition. However, high-efficiency Sb-2(S,Se)(3) solar cells reported up to now are opaque and only permit monofacial absorption, limiting the applicability in some circumstances where semitransparency and the capability of absorbing tilt incident light are demanded. Here, we demonstrate a bifacial and semitransparent Sb-2(S,Se)(3) solar cell enabled by an FTO substrate and ITO back contact. The ultra-thin inner n-i-p structure and transparent conductive oxides (TCOs) offer high transmittance at the long wavelength range. Although the nonideal MnS/ITO interface brings slight band mismatch and an increased defect density, satisfying power conversion efficiencies (PCEs) of 7.41% and 6.36% are nevertheless attained for front and rear absorption respectively. Moreover, our further investigation reveals this innovative bifacial solar cell can well absorb the incident light with 2p tilt angles except the parallel one to the cell. These intriguing results suggest that bifacial and semitransparent Sb-2(S,Se)(3) solar cells have a significant advantage in practical applications.