Recycling of FTO/TiO₂ Substrates: Route toward Simultaneously High-Performance and Cost-Efficient Carbon-Based, All-Inorganic CsPbIBr₂ Solar Cells

Abstract

Carbon-based, all-inorganic perovskite solar cells (PSCs) have drawn enormous attention recently on account of their ungraded stability and reduced costs. However, their power conversion efficiencies (PCEs) still lag behind the ones with conventional architecture. Moreover, the high cost of FTO substrates and energy-consuming sintering process of TiO 2 electrontransporting layers should be further addressed. Herein, it is demonstrated that the FTO/TiO 2 substrates could be separated simply from degraded CsPbIBr 2 PSCs for fabricating the new ones again, which thus reduces the production costs of resulting PSCs and makes them renewable and sustainable. Meanwhile, the characterization results reveal that there are some residual CsPbIBr 2derived species on recycled FTO/TiO 2 substrates, which enable the upper CsPbIBr 2 films with suppressed halide phase separation and reduced defects, the diminished work function of TiO 2 layers from 4.13 to 3.89 eV, along with decreased conduction band minimum (CBM) difference of CsPbIBr 2 /TiO 2 interface from 0.51 to 0.36 eV. Consequently, the average PCE of CsPbIBr 2 PSCs is improved by 20%, from 6.51 ± 0.62% to 8.14 ± 0.63%, wherein the champion one yields the exceptional value of 9.12%. These findings provide an avenue for simultaneous performance enhancement and cost-saving of carbonbased, all-inorganic PSCs to promote their commercialization.

“One-key-reset” recycling of whole perovskite solar cell

“…There still exist residual perovskite-derived species on the recycled ITO/TiO 2 substrates. 13,44 Here we found, using this amineinvolved nonpolar solvent system, that there is no residual perovskite remaining at the SnO 2 surface. This could be ascribed to the strong insertion ability of the amine molecule into the perovskite lattice that can quickly liquefy the perovskite and detach it from the substrate.…”

“…This multi-step process led to the reuse of the TiO 2 -coated FTO substrate and perovskite precursors comprising PbI 2 and MAI for fabricating new solar cells. Recently, Zhu et al 13 employed similar chemicals, using DMF to dissolve the all-inorganic CsPbIBr 2 perovskite, and recycled the FTO/glass for reuse. Chhillar et al 14 demonstrated that degraded perovskite (with a rich PbI 2 phase) could be recovered back to tetragonal perovskite, which can help in minimizing the waste from failed devices to a certain degree.…”

Review of State of the Art Recycling Methods in the Context of Dye Sensitized Solar Cells

“…In their case, they recycled the FTO TiO 2 glass from perovskite cells. They removed the top layers of the perovskite cell and applied fresh CsPbIBr 2 and carbon layers [40]. TiO 2 is commonly used in DSSCs because it is the best trade of between sustainability and efficiency [41].…”

Efficient and Stable All‐Inorganic Perovskite Solar Cells

“…However, Zhang and coworkers [ 156 ] came to a different conclusion in all‐inorganic PSCs based on CE where pinholes were favorable for suppressing carrier nonradiative recombination through forming desirable crystalline grains, The device based on CsPbIBr 2 films with benign pinholes yielded a PCE of 9.06%, which was much higher than 6.19% of the reference device without pinholes. Zhang and coworkers [ 155 ] developed a recycle strategy which enabled the simultaneous achievement of PCE enhancement and cost saving. The champion device based on this recycle strategy produced a PCE of 9.12% due to the suppressed halide separation and reduced defects.…”