Multidimensional Modulation via Tailored Covalent Organic Frameworks Enables Stable Inverted Perovskite Solar Cells with 26.21% Efficiency

Despite the remarkable advancements in inverted perovskite solar cells, their commercialization remains hindered by critical bottlenecks in efficiency and stability stemming from inadequate crystallization and unfavorable interfacial states. Herein, for the first time, a judiciously designed hydrazine-linked covalent organic framework (COF) with long alkane phosphate branch chains, named 12-SD-COF, is synthesized and integrated into the perovskite precursor to achieve multidimensional regulation of crystallization, defect states, and charge separation synergistically. It is found that the 12-SD-COF featuring periodic pores, large planar structure, and abundant binding groups is extruded from the precursor solution onto the buried interface, surface, and grain boundaries, facilitating oriented crystallization while eliminating defects of perovskites, thereby yielding high-quality crystals with suppressed non-radiative recombination. Simultaneously, the interfacial charge separation is synergistically facilitated by the p-type doping-optimized energy level alignment and the induced intramolecular electric field, ultimately achieving an exceptional power conversion efficiency (PCE) of 26.21%, the highest yet reported for COF-modified. Impressively, the non-encapsulated resultant device delivers greatly improved stabilities, with maintaining over 92% of initial PCE after being aged under 85 °C continuous heating stress for 800 h, 1000 h in 50±3% relative humidity air, and 1200 h under continuous 1-sun illumination, respectively.