Shear flow strategy for coating homogeneity of organic materials in perovskite solar cells and modules

The non-uniformity of the perovskite layer is a critical bottleneck limiting performance improvements in large-area perovskite solar cells (PSCs). In the evaporation-solution hybrid method, the Marangoni effect occurs due to variations in local organic material concentration during the coating process, leading to material clustering and coffee-ring effects, which hinder device performance. Here, we discussed the air-blowing process during coating and identified shear flow as the key factor affecting film homogeneity. By modulating the shear flow intensity, the surface tension gradient induced by local concentration differences is adjusted, mitigating the Marangoni effect and resulting in uniform perovskite films. Consequently, perovskite/silicon tandem solar cells (PS-TSCs) achieved 27.36% efficiency (64.64 cm² aperture area), whereas perovskite modules (PSMs) reached 21.83% efficiency (810 cm² aperture area).