Effect of buffer layers on the photovoltaic performance of bifacial transparent perovskite solar cells under different albedo conditions

Abstract

Perovskite solar cells (PSCs) have made significant advancements, achieving a power conversion efficiency of up to 27%. PSCs are easy to manufacture and cost-effective, making them highly attractive for commercial applications. This study focuses on bifacial transparent PSCs, which utilize transparent electrodes instead of metal electrodes, allowing light absorption from both sides and thereby enhancing energy utilization efficiency. The introduction of buffer layers is aimed at protecting the perovskite absorption layer and organic transport layer from damage during the sputtering process of transparent conductive oxides (TCOs). This research evaluates the effectiveness of three buffer layer preparation methods, soft sputtering deposition, spin coating, and atomic layer deposition (ALD), for bifacial PSCs under various illumination conditions. The results indicated that the bifacial devices with ALD-prepared buffer layers exhibit the best performance under specific albedo conditions, with a front-side illuminated efficiency of 16.2% and a rear-side illuminated efficiency of 15.4% under AM 1.5 G illumination (1 sun), resulting in a bifacial factor of 0.95. A MA-free bifacial PSC with a p-i-n architecture of composition FA_0.78Cs_0.22Pb(I_0.85Br_0.15)₃ delivers a front-side (glass-side) illuminated efficiency of 19.7% and a rear-side (IZO-side) illuminated efficiency of 18.0% under AM 1.5 G illumination (1 sun). The device exhibited excellent bifacial characteristics, achieving a bifacial factor of 0.91, with a frontside short-circuit current density (J_sc) of 22.8 mA cm⁻² and a rear-side J_sc of 20.8 mA cm⁻². As the albedo light intensity increases, the bifacial device achieves a significant gain in output power, highlighting the potential of bifacial transparent PSCs in environmental light harvesting scenarios. These results highlight the potential of MA-free perovskite bifacial solar cells as high-efficiency and stable energy conversion candidates, paving the way for further optimization in tandem and large-area photovoltaic applications.