• • Achieved record PCE of 20.01% (certified 19.58%) in HTM-free carbon-based CsPbI3 perovskite solar cells, surpassing previous benchmarks and demonstrating commercial viability for low-cost photovoltaics.
• • TEPM additive coordinates with Pb2+ ions via alkynyl moieties, slowing crystallization kinetics, which increases grain size and crystallinity while reducing defect densities, directly addressing performance-limiting recombination.
• • Unencapsulated devices retained 87.6% of initial efficiency after 1080 h under ambient conditions (25°C, 30% RH), indicating robust environmental stability critical for real-world deployment.
• • Devices maintained 94.0% of initial efficiency after 730 h of continuous AM 1.5G illumination in air, proving operational stability under standard illumination, a key requirement for commercial solar modules.