Single-Junction Bifacial and Semitransparent $\text{Sb}_{2}(\mathrm{S},\text{Se})_{3}$ 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
$\text{Sb}_{2}(\mathrm{S},\text{Se})_{3}$
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 non-ideal 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
$2\pi$
tilt angles except the parallel one to the cell. These intriguing results suggest that bifacial and semitransparent
$\text{Sb}_{2}(\mathrm{S},\text{Se})_{3}$
solar cells have a significant advantage in practical applications.