Performance of Bifacial Lead-Free All-Perovskite Tandem Solar Cell for Indoor Applications

The concept of bifacial tandem solar cell (BTSC) design, allowing light to penetrate the device from both its front and back surfaces, has proven to be a potent strategy for enhancing power conversion efficiency (PCE). In this study, we present the performance evaluation of a novel \({\text {MAGeI}_{3}}\) —2D/3D \({\text {FASnI}_{3}}\) BTSC configuration. The BTSC was concurrently illuminated with AM1.5G solar spectrum from the front surface, while being exposed to various artificial light sources from the back surface. Comprehensive combinations of these artificial lighting conditions were also employed to explore their influence on BTSC performance. Using Silvaco TCAD software, the device architecture was thoroughly optimized. At optimized thicknesses of 130 nm for \({\text {MAGeI}_{3}}\) and 620 nm for 2D/3D \({\text {FASnI}_{3}}\) , the lead-free all-perovskite BTSC (LPBTSC) displayed an impressive peak PCE of 30.29%. This PCE was obtained under simultaneous AM1.5G solar spectrum and halogen lighting illumination. In addition, the LPBTSC was able to achieve an impressive optimum PCE of 58.28% by utilizing an innovative strategy. This remarkable result was observed when blue and white LED sources simultaneously illuminated the device’s front and rear surfaces. The output power density of the LPBTSC falls within the range of 1–29 mW cm \(^{-2}\) , which is sufficient for serving as an effective energy harvester for Internet of Things (IoT) and indoor applications, all while maintaining low fabrication costs. This study underscores the immense potential of bifacial tandem solar cells in effectively harnessing a diverse array of lighting conditions, offering promising prospects for various practical applications.