Enhanced infiltration and morphology of bismuth perovskite in Carbon-stack solar cells – A synergistic effect of electric fields in modified spray technique

• Published in: Solar energy Vol. 241; pp. 386 - 395
• Main Authors: Bhavani Korukunda, Tulja, Joshi, Dhavalkumar N., Meroni, Simone, Watson, Trystan, Dutta, Viresh
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-07-2022
• Subjects: Bismuth perovskite; Carbon stack devices; Greener solvent; Perovskite; Solvent engineering; Spray coating; Bismuth perovskite; Perovskite; Carbon stack devices; Spray coating; Greener solvent; Solvent engineering
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2022.06.021

Improved infiltration of Bi-perovskite in C-PSC stack via modified spray coating using electric field across the nozzle (M-EF) and an additional electric field at the substrate (AM-EF).
[Display omitted]
•Infiltration of perovskite in C-PSCs is a key factor for the device performance.•Spray in conjunction with electric fields (EF) is used to infilter Bismuth perovskite.•The EF enhanced crystallinity, opto-electric properties and stability of perovskite.•Improved perovskite infiltration is reflected in boosting Jsc of the device.•Greener solvent system-based perovskite ink is used for spray deposition.
Carbon-based perovskite solar cell (C-PSC) is the breakthrough device architecture, with all printable layers, owing to its ease of fabrication and scope of commercialization. However, infiltration of the perovskite into this prefabricated monolithic C-PSC is a cumbersome process since it needs the adequate material to reach the mesoporous TiO2 (m-TiO2) layer through a thick C- electrode and ZrO2 (separator) and crystallize uniformly. Herein, using the modified electric field (EF) assisted spray technique and with a greener solvent system for the Bismuth Perovskite (Bi-perovskite), its infiltration in the C-PSC stack is demonstrated. A conventional spray system is modified with two different EFs at the nozzle (M−EF) and the substrate (A-EF). The developed protocol promotes controlled infiltration of perovskite at a faster rate (∼2 mins), addressing the infiltration issue in C-PSCs.
Consequently, the efficiency of spray devices is improved by ∼ 80% compared to the drop-casted devices. The enhanced stability of the Bi-perovskite, resulting from the selective plane growth, suggests another significant improvement by employing the proposed spray technique. The substantial efficiency and stability improvement attained using a greener solvent system (Acetone-DMF) add an advantage to the process. Hence, the work highlights the first-ever spray-processed non-lead perovskite using the greener solvent system for a large area hole transport layer (HTL) free C-PSC device.