Binder-solvent effects on low temperature-processed carbon-based, hole-transport layer free perovskite solar cells

• Published in: Materials chemistry and physics 2020-12, Vol.256, p.123594, Article 123594
• Main Authors: Kartikay, Purnendu, Yella, Aswani, Mallick, Sudhanshu
• Format: Article
• Language: English
• Subjects: Absorbers; Absorption spectra; Binders; Carbon; Cellulose; Degradation; Diffusion barriers; Diffusion layers; Energy conversion efficiency; Ethyl cellulose; HTM free; Low temperature; Low-temperature carbon electrode; Pastes; Perovskite solar cell; Perovskites; Photovoltaic cells; Polymethyl methacrylate; Solar cells; Solvent effect; Solvents; Stability; Titanium dioxide
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2020.123594

Hole transport layer and expensive metallic counter electrode free low-temperature processed, economical carbon-based perovskite solar cells are fabricated. Carbon pastes with different binders (ethyl cellulose, PVP and PMMA) and three different solvents are prepared and their perovskite compatibility is studied. The prepared carbon pastes are adherent and have low sheet resistance (8.43 Ω □−1), which is directly printed on top of FA1-xMAxPbI3-yBry based perovskite absorber layer. UV–vis absorption spectra and XRD analysis are performed to study long-term binder-induced degradation of the perovskite absorber layer. The hydrophobic carbon layer effectively blocks the moisture diffusion into the perovskite layer. The results suggest ethyl cellulose and PMMA based binders enhance the perovskite layer stability, whereas, in PVP based binder, some initial degradation is observed due to the presence of hydrophilic moiety. The perovskite solar cell with the FTO/TiO2 compact layer/TiO2 mesoporous layer/perovskite/carbon architecture is fabricated. The fabricated devices with PMMA based binder show the highest power conversion efficiency >10% and encouraging stability for more than 700 h for un-encapsulated devices in ambient conditions retaining more than 50% of its initial efficiency. [Display omitted] •Developed low-temperature curable hydrophobic carbon paste having low sheet resistance with different binders and solvents.•Study of carbon paste “binder” induced perovskite layer degradation.•FA1-xMAxPbI3-yBry based perovskite solar cell fabrication with hydrophobic carbon layer on top.•Un-encapsulated devices kept in ambient having T80 more than 400 h and significant stability for one month.