Dual-functional tartaric acid additive realizing high-quality perovskite film through chemical passivation and crystallization regulation

Abstract

Highly crystalline perovskite absorbers with low defect-state densities minimizing nonradiative recombination losses are a critical prerequisite for fabricating state-of-the-art photovoltaics. Here, we use a tartaric acid (TA) molecule with two carboxyl and two hydroxyl groups as an additive to improve the performance and stability of the device simultaneously. The strong carboxyl-Pb²⁺ coordination slows nucleation kinetics and passivates Pb-related traps, whereas hydroxyl-I⁻ hydrogen bonding can modulate grain growth and stabilize the lattice structure, collectively enabling low-defect-density and high-quality perovskite films. Besides, we also conducted quantitively loss analysis and confirmed that the TA addition effectively reduces trap-assisted non-radiative recombination. Consequently, the champion efficiency of the n-i-p structure is up to 24.77% with outstanding operational and humidity stability. Remarkably, in the triple-cation perovskite system, the incorporation of the TA additive similarly enabled the fabrication of high-quality films, ultimately yielding a p-i-n configuration with a champion efficiency of 26.11%.