Crystallinity Control and Strain Release in Wide-Bandgap Perovskite Film via Seed-Induced Growth for Efficient Photovoltaics.

ABSTRACT

The seed method stands out as a straightforward and efficient approach for fabricating high-performance perovskite solar cells (PSCs). In this study, we propose the utilization of an antisolvent as an additive to induce crystal seeding, thereby facilitating the growth of wide-bandgap perovskite grains. Specifically, we introduce three commonly used antisolvents─ethyl acetate (EA), isopropanol (IPA), and chlorobenzene (CB)─directly into the perovskite precursor solution to generate perovskite seeds, which serve to promote subsequent nucleation. This antisolvent-crystal seeding method (ACSM) results in increased grain sizes, reduced film defects, and overall improved film quality. Consequently, the power conversion efficiencies (PCEs) of 1.647 eV PSCs with EA, IPA, and CB additives are recorded at 19.86%, 20.61%, and 20.45%, respectively, surpassing that of the reference device with a PCE of 18.83%. Furthermore, the stability of the PSCs prepared through ACSM is notably enhanced. Notably, PSCs optimized with IPA retain 75% of the original PCE after being stored in ambient air conditions (25 °C, RH ∼ 15%) for 30 days, better than the CB-added (64%) and the EA-added devices (53%), while the reference devices only retain 31% of the initial PCE. Moreover, even after continuous thermal annealing at 50 °C for 200 h, IPA-assisted devices demonstrate the best stability, followed by those with CB and EA, with the reference exhibiting the poorest stability.