Linked Nickel Oxide/Perovskite Interface Passivation for High-Performance Textured Monolithic Tandem Solar Cells

Sputtered nickel oxide (NiO_x) is an attractive hole-transport layer for efficient, stable, and large-area p-i-n metal-halide perovskite solar cells (PSCs). However, surface traps and undesirable chemical reactions at the NiO_x/perovskite interface are limiting the performance of NiO_x-based PSCs. To address these issues simultaneously, an efficient NiO_x/perovskite interface passivation strategy by using an organometallic dye molecule (N719) is reported. This molecule concurrently passivates NiO_x and perovskite surface traps, and facilitates charge transport. Consequently, the power conversion efficiency (PCE) of single-junction p-i-n PSCs increases from 17.3% to 20.4% (the highest reported value for sputtered-NiO_x based PSCs). Notably, the N719 molecule self-anchors and conformally covers NiO_x films deposited on complex surfaces. This enables highly efficient textured monolithic p-i-n perovskite/silicon tandem solar cells, reaching PCEs up to 26.2% (23.5% without dye passivation) with a high processing yield. The N719 layer also forms a barrier that prevents undesirable chemical reactions at the NiO_x/perovskite interface, significantly improving device stability. These findings provide critical insights for improved passivation of the NiO_x/perovskite interface, and the fabrication of highly efficient, robust, and large-area perovskite-based optoelectronic devices.