Surface Passivation with Glyoxylic Acid for Stable and Enhanced Device Performance of Perovskite Solar Cells

Perovskite solar cells (PSCs) have emerged as one of the most promising solution-processed photovoltaic technologies, with single-junction PSCs achieving power conversion efficiencies (PCEs) exceeding 25%. However, their performance is hindered by the ionic nature of perovskite absorbers, which exhibit low formation energies of halide vacancies. These vacancies contribute to efficiency degradation by inducing non-radiative recombination at defective antisites. To address these issues, we introduce glyoxylic acid (GXA) as a novel passivating agent for perovskite films in inverted-structured PSCs. The two carbonyl groups in GXA engage in Lewis acid-base interactions with undercoordinated Pb²⁺ ions in the [PbI₆] framework of the perovskite lattice, effectively suppressing major defects in the perovskite layers. Additionally, GXA acts as a hydrogen bond acceptor with iodide ions in the lattice, further enhancing its role as a potent passivating agent. This approach successfully reduces defect densities, resulting in smoother film surfaces and diminished remnant PbI₂ contents in the films. Encouragingly, the devices incorporating GXA achieved a high PCE of 22.41%, along with an improved open-circuit voltage of 1.12 V and a fill factor above 82%. The optimized devices passivated with GXA also demonstrated excellent operational stability in continuous 1-sun illumination in ambient condition. Further details regarding the film properties and device analyses will be discussed in the poster presentation.