Immobilizing Surface Halide in Perovskite Solar Cells via Calix[4]pyrrole

Abstract

Halide diffusion across the charge‐transporting layer followed by a reaction with metal electrode represents a critical factor limiting the long‐term stability of perovskite solar cells (PSCs). In this work, a supramolecular strategy with surface anion complexation is reported for enhancing the light and thermal stability of perovskite films, as well as devices. Calix[4]pyrrole (C[4]P) is demonstrated as a unique anion‐binding agent for stabilizing the structure of perovskite by anchoring surface halides, which increases the activation energy for halide migration, thus effectively suppressing the halide–metal electrode reactions. The C[4]P‐stabilized perovskite films preserve their initial morphology after ageing at 85 °C or under 1 sun illumination in humid air over 50 h, significantly outperforming the control samples. This strategy radically tackles the halide outward‐diffusion issue without sacrificing charge extraction. Inverted‐structured PSCs based on C[4]P modified formamidinium–cesium perovskite exhibit a champion power conversion efficiency of over 23%. The lifespans of unsealed PSCs are unprecedentedly prolonged from dozens of hours to over 2000 h under operation (ISOS‐L‐1) and 85 °C ageing (ISOS‐D‐2). When subjected to a harsher protocol of ISOS‐L‐2 with both light and thermal stresses, the C[4]P‐based PSCs maintain 87% of original efficiency after ageing for 500 h.

Flexible Backbone-Assisted Green-Solvent Processable Polymer Hole Transport Material in Perovskite Solar Cells

“…Correspondingly, the N 1s peak of N–H for the A-EDOT/perovskite is located at 399.94 eV, while it moves to 400.06 eV for the pristine A-EDOT film (Figure f). The downshift of I 3d spectra and the upshift of N 1s spectra confirm the formation of hydrogen bonds (N–H···I) between the A-EDOT and perovskite, which favors the improvement of the film morphology of perovksite. ,, …”

Metal-Free Hydrazinium Halide Perovskitoid Single Crystals for X-ray Detection

“…From the main hydrogen bond interaction diagram in Figure e, with the introduction of N 2 H 5 + components, the main hydrogen bonding forces change from the previous A-site to X-site and B-site to X-site in DABCO-NH 4 Br 3 to the dominant B-site to B-site in DABCO-N 2 H 5 Br 3 . Moreover, it was reconfirmed by the IGMH (Independent Gradient Model based on Hirshfeld partition) in Figure f. − Mulliken charge is also adopted to reflect the different hydrogen bonding reactions for the different B-site components. The larger potential difference between DABCO-NH and Br increases the hydrogen bond strength compared to DABCO-NH 4 Br 3 , further demonstrating the superiority of the N 2 H 5 + component (Figure g) …”

Cross-linking strategies for efficient and highly stable perovskite solar cells

“…Specific chemical interactions ( e.g. , Lewis acid–base interaction, 211 hydrogen bonding, 212,213 halogen bonding, 214 chelation effect, 215,216 π–π interaction, 217 cation–π interaction, 218 and anion complexation 219 ) are proven to be conducive to heal the defects either at the perovskite GBs or at the interfaces between perovskite and adjacent layers. However, such interactions may be weakened over long-term operation due to high diffusion coefficient of organic species.…”