Chloride‐Based Additive Engineering for Efficient and Stable Wide‐Bandgap Perovskite Solar Cells

• Published in: Advanced materials (Weinheim) Vol. 35; no. 30; pp. e2211742 - n/a
• Main Authors: Shen, Xinyi, Gallant, Benjamin M., Holzhey, Philippe, Smith, Joel A., Elmestekawy, Karim A., Yuan, Zhongcheng, Rathnayake, P. V. G. M., Bernardi, Stefano, Dasgupta, Akash, Kasparavicius, Ernestas, Malinauskas, Tadas, Caprioglio, Pietro, Shargaieva, Oleksandra, Lin, Yen‐Hung, McCarthy, Melissa M., Unger, Eva, Getautis, Vytautas, Widmer‐Cooper, Asaph, Herz, Laura M., Snaith, Henry J.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.07.2023
• Subjects: additive engineering; Additives; Chemical Sciences; Chlorides; Circuits; Crystallization; crystallization mechanism; Electric potential; Energy conversion efficiency; Energy gap; halide homogenization; Kemi; Materialkemi; Materials Chemistry; Materials science; Metal halides; Natural Sciences; Naturvetenskap; Optoelectronics; perovskite solar cells; Perovskites; Photovoltaic cells; Self-assembly; Solar cells; suppressed halide segregation; Voltage; suppressed halide segregation; additive engineering; halide homogenization; perovskite solar cells; crystallization mechanism
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202211742

Metal halide perovskite based tandem solar cells are promising to achieve power conversion efficiency beyond the theoretical limit of their single‐junction counterparts. However, overcoming the significant open‐circuit voltage deficit present in wide‐bandgap perovskite solar cells remains a major hurdle for realizing efficient and stable perovskite tandem cells. Here, a holistic approach to overcoming challenges in 1.8 eV perovskite solar cells is reported by engineering the perovskite crystallization pathway by means of chloride additives. In conjunction with employing a self‐assembled monolayer as the hole‐transport layer, an open‐circuit voltage of 1.25 V and a power conversion efficiency of 17.0% are achieved. The key role of methylammonium chloride addition is elucidated in facilitating the growth of a chloride‐rich intermediate phase that directs crystallization of the desired cubic perovskite phase and induces more effective halide homogenization. The as‐formed 1.8 eV perovskite demonstrates suppressed halide segregation and improved optoelectronic properties. The key role of methylammonium chloride additive in directing the crystallization of 1.8 eV perovskites to induce more effective halide homogenization is elucidated. The as‐formed perovskite demonstrates suppressed halide segregation, improved optoelectronic properties, and ambient stability. In conjunction with a self‐assembled monolayer (Me‐4PACz), a VOC of 1.25 V and steady‐state PCE of 17% are achieved.