Achieving bifacial photovoltaic performance in PTB7-based organic solar cell by integrating transparent contact for emerging semi-transparent applications

In this study, the design, fabrication and detailed analysis of semi-transparent bifacial organic solar cells (ST-OSC) based on MoO₃/Ag/WO₃ (10/d_m/d_od nm) dielectric/metal/dielectric (DMD) transparent contact system integrated with PTB7 polymer were investigated. The study emphasizes the importance of designing transparent contact systems to optimize the solar cells' transparency (average visible transmittance, AVT), color rendering (color rendering index, CRI), efficiency (power conversion efficiency, PCE), and bifaciality. The performance of three distinct configurations was examined in the AVT_max (47.14% AVT, 3.93% PCE), (CRI_ext)_max (23.82% AVT, 6.21% PCE), and Extreme Color (26.34% AVT, 5.81% PCE). The theoretically predicted AVTs for these configurations were 48.75%, 22.29%, and 25.15%, respectively. The strong agreement between theoretical and observed outcomes confirmed the accuracy of the Transfer Matrix Model (TMM). Furthermore, the assessment of bifaciality performance exhibited that the AVT_max had a bifaciality factor of 0.94, with a PCE of 3.67% under top illumination and 3.93% under bottom illumination. The high bifaciality of the structure designed with TMM to maximize the AVT demonstrates the value of calculations prior to solar cell structure fabricating and the possibility of constructing high bifaciality structures using this technique.