Numerical Analysis and Comparison of Bifacial Indoor Photovoltaic Devices with Chalcogenide, Kesterite and II-VI Compounds

Bifacial photovoltaic (BPV) devices have gained attention in the recent times for various applications including indoor photovoltaics. This paper presents a numerical study to analyze the performance of bifacial photovoltaic devices is carried out with solar and cool white LED sources for three absorber materials: chalcogenide, kesterite, and II-VI. CuInGaSe2 (CIGS), CuZnSn(S,Se)4 (CZTSSe), and CdTe were selected to represent these materials, and their monofacial performance was evaluated first. Among all scenarios, front LED and rear solar illumination produced the highest bifacial 1.3 efficiencies: $17.6 \%$ (CIGS) and $11.1 \%$ (CZTSSe). The CdTe cell showed its best bifacial 1.3 efficiency of $16.7 \%$ under white LED illumination on both front and back surfaces. Although the bifacial efficiencies of CZTSSe and CdTe were lower than their monofacial counterparts, these devices exhibited significantly increased short-circuit current densities and stable open-circuit voltages. The highest short-circuit current densities observed were $68.98 \mathrm{~mA} / \mathrm{cm}^{2}, 43.09 \mathrm{~mA} / \mathrm{cm}^{2}$, and $41.94 \mathrm{~mA} / \mathrm{cm}^{2}$ for the CIGS, CZTSSe and CdTe devices, respectively. CIGS’s superior bifacial performance was attributed to the spectrum-dependent carrier generation and recombination dynamics in the n-p heterojunction.