An Equalized Flow Velocity Strategy for Perovskite Colloidal Particles in Flexible Perovskite Solar Cells.

The non-uniform distribution of colloidal particles in perovskite precursor results in an imbalanced response to the shear force during flexible printing process. Herein, we have observed that the continuous disordered migration occurring in perovskite inks significantly contributes to the enlargement of colloidal particles size and diminishes the crystallization activity of the inks. Therefore, we have devised a molecular encapsulation architecture by glycerol monostearate (GMS) to mitigate colloidal particles collisions in the precursor ink, while simultaneously homogenizing the size distribution of perovskite colloids to minimize their diffusion disparities. The utilization of colloidal particles with a molecular encapsulation structure enables the achievement of uniform deposition during the printing process, thereby effectively balancing the crystallization rate and phase transition in the film and facilitating homogeneous crystallization of perovskite films. The large-area flexible perovskite device (1.01 cm 2 and 100 cm 2 ) fabricated through printing processes, achieved an efficiency of 24.45% and 15.87%, respectively, and manifest superior environmental stability, maintained an initial efficiency of 91% after being stored in atmospheric ambiences for 150 days (unencapsulated). This work demonstrates that the dynamics evolution process of colloidal particles in both the precursor ink and printing process represents a crucial stride towards achieving uniform crystallization of perovskite films. This article is protected by copyright. All rights reserved.