Sajid Sajid, Alzahmi Salem, Salem Imen Ben, Obaidat Ihab M
Department of Chemical & Petroleum Engineering, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates.
National Water and Energy Center, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates.
Nanomaterials (Basel). 2022 Sep 26;12(19):3352. doi: 10.3390/nano12193352.
The conventional post-annealing (CPA) process is frequently employed and regarded a crucial step for high-quality perovskite thin-films. However, most researchers end up with unwanted characteristics because controlling the evaporation rate of perovskite precursor solvents during heat treatment is difficult. Most perovskite thin-films result in rough surfaces with pinholes and small grains with multiple boundaries, if the evaporation of precursor solvents is not controlled in a timely manner, which negatively affects the performance of perovskite solar cells (PSCs). Here, we present a surface-confined post-annealing (SCPA) approach for controlling the evaporation of perovskite precursor solvents and promoting crystallinity, homogeneity, and surface morphology of the resulting perovskites. The SCPA method not only modulates the evaporation of residual solvents, resulting in pinhole-free thin-films with large grains and fewer grain boundaries, but it also reduces recombination sites and facilitates the transport of charges in the resulting perovskite thin-films. When the method is changed from CPA to SCPA, the power conversion efficiency of PSC improves from 18.94% to 21.59%. Furthermore, as compared to their CPA-based counterparts, SCPA-based PSCs have less hysteresis and increased long-term stability. The SCPA is a potentially universal method for improving the performance and stability of PSCs by modulating the quality of perovskite thin-films.
传统的退火后处理（CPA）工艺经常被采用，并被视为高质量钙钛矿薄膜的关键步骤。然而，大多数研究人员最终得到的是不理想的特性，因为在热处理过程中控制钙钛矿前驱体溶剂的蒸发速率很困难。如果前驱体溶剂的蒸发没有得到及时控制，大多数钙钛矿薄膜会形成表面粗糙、有针孔且晶粒小、晶界多的情况，这会对钙钛矿太阳能电池（PSC）的性能产生负面影响。在此，我们提出一种表面受限退火后处理（SCPA）方法，用于控制钙钛矿前驱体溶剂的蒸发，并促进所得钙钛矿的结晶度、均匀性和表面形态。SCPA方法不仅能调节残留溶剂的蒸发，从而得到无针孔、晶粒大且晶界少的薄膜，还能减少复合位点，并促进所得钙钛矿薄膜中的电荷传输。当方法从CPA改为SCPA时，PSC的功率转换效率从18.94%提高到了21.59%。此外，与基于CPA的PSC相比，基于SCPA的PSC滞后现象更少，长期稳定性更高。SCPA是一种通过调节钙钛矿薄膜质量来提高PSC性能和稳定性的潜在通用方法。
