Bifacial And Semitransparent Sb 2 (S,Se) 3 Solar Cells for Single-Junction And Tandem Photovoltaic Applications.

Thin film solar cells, as a complement to silicon solar cells, are expected to play a significant role in the space industry, building integrated photovoltaic (BIPV), indoor applications and tandem solar cells, where bifaciality and semitransparency are highly desired. Sb (S,Se) has emerged as a promising new photovoltaic (PV) material for its high absorption coefficient, tuneable bandgap, and non-toxic and earth-abundant constituents. However, high-efficiency Sb (S,Se) solar cells so far exclusively employ gold back contacts or Mo-coated glass substrates, which only allows monofacial architectures, leaving a considerable gap towards large-scale application in aforementioned fields. Here, we report a bifacial and semitransparent Sb (S,Se) solar cell enabled by a fluorine-doped tin oxide substrate and an indium tin oxide (ITO) back contact, and its extended application in tandem solar cells. The transparent conductive oxides (TCOs) and the ultra-thin inner n-i-p structure provide high transmittance at the long wavelength region. Despite of the unfavourable Schottky junction and increased defect density at MnS/ITO interface, a power conversion efficiency (PCE) of 7.41% with only front illumination is achieved. On the other hand, though the varied carrier kinetic with rear illumination has a negative impact on the PCE, the internal ultrathin fully depleted absorber layer enables it to remain at a satisfying level at 6.36%, contributing to a great bifaciality of 0.86. As a result, our bifacial and semitransparent Sb (S,Se) solar cells can gain great enhancement in PV performance by exploiting albedo of surroundings and show exceptional capability in absorbing non-normal incident light. Moreover, our device can be integrated into a tandem solar cell with a bottom silicon solar cell owing to its adjustable bandgap. A Sb (S,Se) /Si tandem solar cell with PCE of 11.66% is achieved in our preliminary trial. These exciting findings imply that bifacial and semitransparent Sb (S,Se) solar cells possess tremendous potential in practical applications based on their unique characteristics. This article is protected by copyright. All rights reserved.