High-Efficiency (>14%) and Air-Stable Carbon-Based, All-Inorganic CsPbI₂Br Perovskite Solar Cells through a Top-Seeded Growth Strategy

Abstract

The inferior crystallinity and phase stability of CsPbI2Br films have severely hindered the development of carbon-based, all-inorganic perovskite solar cells (PSCs). Herein, we demonstrate the preparation of CsPbI2Br films by the top-seeded solution growth (TSSG) technique. It is performed through spin-coating of CH3NH3Br (MABr) atop CsPbI2Br precursor film prior to annealing, during which perovskite seeds are generated atop it. These perovskite seeds not only serve as nuclei to regulate the growth of CsPbI2Br grains but also provide additional Br– anions to generate a thin Br-rich layer atop the final CsPbI2Br film. The former contributes to the formation of CsPbI2Br film with full coverage, larger grains, higher crystallinity, and fewer electronic defects, while the latter gives rise to residual compressive strain along the film and thus markedly boosts its phase stability. Consequently, the optimized carbon-based, all-inorganic PSC exhibits a much better efficiency of 14.84% coupled with favored storage and operational stability.

Generic water-based spray-assisted growth for scalable high-efficiency carbon-electrode all-inorganic perovskite solar cells

“…Similar to the optimized preparation recipe of CsPbBr 3 films, CsPbCl 5A. The color of the each of the films well consists with their bandgaps (Zhu et al, 2021;Zhu et al, 2020;Zhou et al, 2018). As expected, highly uniform CsPbCl 3 , CsPbIBr 2 , and CsPbI 2 Br films were obtained by the waterbased spray-assisted growth strategy.…”

“…All-inorganic perovskite materials investigated for carbon-electrode, all-inorganic PSCs mainly include CsPbI 3 (Wang et al, 2021;Xiang et al, 2018Xiang et al, , 2019, CsPbI 2 Br (Dong et al, 2019;He et al, 2020;Lin et al, 2020;Zhu et al, 2021), CsPbIBr 2 (Du et al, 2021;Zhu et al, 2018), and CsPbBr 3 (Chang et al, 2016;Duan et al, 2018b), and the performance of resulting carbon-electrode, all-inorganic PSCs has advanced rapidly in recent years. To be specific, since the first report of carbon-electrode CsPbBr 3 PSC in 2016 (Chang et al, 2016), its PCE has been promoted from 5.0% to 10.85% (Chang et al, 2016;Duan et al, 2020).…”

“…When a hole booster composed of graphene oxide and (NiCo) 1-y Fe y O x is adopted, the PCE of carbon-electrode CsPbIBr 2 PSC can reach up to 10.95% (Du et al, 2021). We demonstrated a top-seeded growth strategy in our laboratory which enables carbon-electrode CsPbI 2 Br PSC with a record-high PCE of 14.84% (Zhu et al, 2021). By use of a PbI 2 -passivated CsPbI 3 film, a PCE of 14.6% was achieved for the PSC (Wang et al, 2021).…”

“…J-V curves of the best-performing PSCs based on CsPbCl 3 , CsPbIBr 2 , and CsPbI 2 Br films are shown in Figure 5D, and detailed photovoltaic parameters are given in TableS2. PCEs of 1.27%, 10.44%, and 13.30% were realized for PSCs fabricated with CsPbCl 3 , CsPbIBr 2 , and CsPbI 2 Br films, respectively, all of which rank among the highest-performing all-inorganic PSCs reported to date(Du et al, 2021;Zhu et al, 2021). In addition, the EQE spectra of the related PSCs in FigureS4show that photocurrent onsets are well in accordance with the absorption characters of CsPbCl 3 , CsPbIBr 2 , and CsPbI 2 Br films, revealing that these inorganic perovskite films dominate their photoelectric conversion process.…”

Growth Temperature Influence on Atomic-Layer-Deposited In2O3 Thin Films and Their Application in Inorganic Perovskite Solar Cells

“…This ETL plays a critical role in effectively extracting the electrons, and efficiently transporting photogenerated electrons from perovskite to ETL at the ETL/perovskite interface constrains charge recombination. In planar PSCs, a thin, compact TiO 2 layer is typically used as inorganic ETL and achieved remarkable PCEs [ 8 ]. For that, an excellent TiO 2 film requires thermal treatment at high temperatures of ≥500 °C, which is incongruous for the fabrication for flexible substrate, including reducing PSCs’ stability due to its photocatalytic effect [ 9 ].…”