Suppressing wide-angle light loss and non-radiative recombination for efficient perovskite solar cells

Surface reflections and non-radiative recombinations create energy losses in perovskite solar cells (PSCs) by hindering the generation and extraction of carriers. These losses can reduce device efficiency in practical applications as the incident angle of sunlight varies throughout the day. Here we introduce a universal strategy to address this issue by coating glass substrates with highly distributed nanoplates of fluorine-doped tin oxide (NP-FTO). An electron-selective homojunction is then formed with a thin layer of SnO₂ deposited by atomic layer deposition covered with SnO₂ quantum dots. Systematic mechanistic studies reveal the exceptional ability of NP-FTO to harvest photons omnidirectionally and its beneficial influence on perovskite crystallization. These combined effects result in substantial improvements in the short-circuit current density, open-circuit voltage and fill factor of n–i–p PSCs under wide-angle incident light illumination. The best-performing PSC achieves a remarkable power conversion efficiency (PCE) of 26.4% (certified 25.9%) under AM1.5G illumination. The devices also show exceptional stability, retaining 95% of their initial PCE after 1,200 hours of light soaking under simulated solar intensity with maximum power point tracking. Moreover, the beneficial effects of NP-FTO are also applicable to 1.77 eV wide-bandgap PSCs with a p–i–n structure, enabling the fabrication of all-perovskite tandem solar cells with a best PCE of 28.2%.