Vapor and healing treatment for CH 3 NH 3 PbI 3−x Cl x films toward large-area perovskite solar cells

• Published in: Nanoscale 2016, Vol.8 (12), p.6386-6392
• Main Authors: Gouda, Laxman, Gottesman, Ronen, Tirosh, Shay, Haltzi, Eynav, Hu, Jiangang, Ginsburg, Adam, Keller, David A., Bouhadana, Yaniv, Zaban, Arie
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/C5NR08658B

Hybrid methyl-ammonium lead trihalide perovskites are promising low-cost materials for use in solar cells and other optoelectronic applications. With a certified photovoltaic conversion efficiency record of 20.1%, scale-up for commercial purposes is already underway. However, preparation of large-area perovskite films remains a challenge, and films of perovskites on large electrodes suffer from non-uniform performance. Thus, production and characterization of the lateral uniformity of large-area films is a crucial step towards scale-up of devices. In this paper, we present a reproducible method for improving the lateral uniformity and performance of large-area perovskite solar cells (32 cm 2 ). The method is based on methyl-ammonium iodide (MAI) vapor treatment as a new step in the sequential deposition of perovskite films. Following the MAI vapor treatment, we used high throughput techniques to map the photovoltaic performance throughout the large-area device. The lateral uniformity and performance of all photovoltaic parameters ( V oc , J sc , Fill Factor, Photo-conversion efficiency) increased, with an overall improved photo-conversion efficiency of ∼100% following a vapor treatment at 140 °C. Based on XRD and photoluminescence measurements, We propose that the MAI treatment promotes a “healing effect” to the perovskite film which increases the lateral uniformity across the large-area solar cell. Thus, the straightforward MAI vapor treatment is highly beneficial for large scale commercialization of perovskite solar cells, regardless of the specific deposition method.