Effect of buffer layer 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) under various illumination conditions. As a result, it is indicated that the bifacial devices with ALD-prepared buffer layers exhibit 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 1.5G illumination (1 sun), resulting in a bifacial factor of 0.95. A MA-free bifacial perovskite cell with a p-i-n architecture of composition FA0.78Cs0.22Pb(I0.85Br0.15)3 delivers front-side illuminated efficiency of 19.7% and a rear-side illuminated efficiency of 18.0% under AM 1.5G illumination (1 sun). The device exhibited excellent bifacial characteristics, achieving a bifacial factor of 0.91, with a frontside (glass-side) short-circuit current density (Jsc) of 22.8 mA/cm2 and a rear-side (IZO-side) Jsc of 20.8 mA/cm2. As the albedo light intensity increases, the bifacial device received 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 candidate, paving the way for further optimizations in tandem and large-area photovoltaic applications.