Perovskite Ink with an Ultrawide Processing Window for Efficient and Scalable Perovskite Solar Cells in Ambient Air

Abstract

Perovskite solar cells (PSCs) have attracted tremendous attention because of their rapidly growing efficiency and low cost. However, the efficiency of scalably deposited PSCs, especially spray-coated devices, is still lagging far behind that of spin-coated devices because of the complicated crystallization of coated precursor ink. Here, we show a precursor ink with an ultrawide processing window (more than 40 min) for spray-coating by adjusting the precursor component, which benefits the scalable deposition of perovskite films. Coupled with antisolvent extraction and addition of methylamine chloride to perovskite ink, high-quality perovskite films were achieved with large-scale uniformity. A power conversion efficiency (PCE) of 18.5% for rigid sprayed PSCs and 16.15% for flexible sprayed PSCs were achieved. At the square-centimeter level, sprayed PSCs on rigid and flexible substrates were achieved with PCEs of 15.07 and 13.21%, respectively. The one-step single-pass spraying method for versatility substrates at a deposition rate of 540 m h–1 brings great prospects for commercialization of PSCs.

Development of Spray-Coated Perovskite Solar Cells

“…The next efficiency breakthrough came in late 2019, when Su et al reported devices with a PCE of 18.53% by optimizing the work of Uličná. 70 Here, the same solvent composition of NMP and DMF was used to spray cast devices, with the perovskite film subsequently dipped in a bath of diethyl ether antisolvent. This process is illustrated schematically in Figure 6 a; here, the film was deposited in a single spray pass before being submerged in an antisolvent bath and then subsequently annealed.…”

“…Such large devices demonstrated reverse scan PCE values of 15.07 and 13.21%, respectively, which are some of the highest values reported in the literature. 70 …”

“…Here, V 0 is the threshold between wet and dry spray modes. Reproduced with permission from ref ( 70 ). Copyright American Chemical Society 2019.…”

Fully Spray-Coated Triple-Cation Perovskite Solar Cells

“…These include the use of two-step deposition protocols 16 , continuous soaking of the substrate 17 , anti-solvent bath treatments 18 , the use of multiple spray-passes 19 , low vacuum treatments 20 , megasonic spray-coating 21 , and hot-air treatments 22 . Indeed, many groups can now reliably produce spray-coated PSCs with an average PCE in the mid-teens with the best devices reaching a reverse scan PCE of 18.5% and a stabilised PCE of 17.3% 23 . Furthermore spray deposition has been utilised to probe compositional space in mixed cation systems by controlling the flow of two inks delivered to the spray head prior to atomisation 24,25 .…”

“…It is important to emphasize that the majority of papers on spray-coated PSCs rely on spin-coating to deposit the electron and hole transport layers that are used to extract charges from the active perovskite layer [16][17][18][19][20][21][22][23]26,27 . Ideally however, spray-coating should be used to deposit all solution processable layers within a PSC as this would replicate a practical manufacture process.…”