Control of Crystal Growth toward Scalable Fabrication of Perovskite Solar Cells

With the impressive record power conversion efficiency (PCE) of perovskite solar cells exceeding 23%, research focus now shifts onto issues closely related to commercialization. One of the critical hurdles is to minimize the cell-to-module PCE loss while the device is being developed on a large scale. Since a solution-based spin-coating process is limited to scalability, establishment of a scalable deposition process of perovskite layers is a prerequisite for large-area perovskite solar modules. Herein, this paper reports on the recent progress of large-area perovskite solar cells. A deeper understanding of the crystallization of perovskite films is indeed essential for large-area perovskite film formation. Various large-area coating methods are proposed including blade, slot-die, evaporation, and post-treatment, where blade-coating and gas post-treatment have so far demonstrated better PCEs for an area larger than 10 cm². However, PCE loss rate is estimated to be 1.4 × 10⁻²% cm⁻², which is 82 and 3.5 times higher than crystalline Si (1.7 × 10⁻⁴% cm⁻²) and thin film technologies (≈4 × 10⁻³% cm⁻²) respectively. Therefore, minimizing PCE loss upon scaling-up is expected to lead to PCE over 20% in case of cell efficiency of >23%.