Unavoidable defects in grain boundaries (GBs) are detrimental and critically influence the organometal halide perovskite performance and stability. To address this issue, semiconducting molecules have been employed to passivate traps along perovskite GBs. Here, we designed and synthesized three squaraine molecules (SQ) with zwitterionic structure to interact with under-coordinated Pb2+ and passivate Pb–I antisite defects. Density functional theory calculation shows symmetric O atoms could coordinate with perovskite grains simultaneously, resulting in continuous charge distribution at the SQ–perovskite interface. The energetic traps distribution in CH3NH3PbI3 perovskite is influenced significantly by the interaction between SQ and perovskite as analyzed by thermally stimulated current, in which the deep-level defects are considerably reduced due to efficient SQ passivation. In addition, we explore how SQ molecules with different energy offset affect the charge extraction, which is suggested to facilitate exciton separation at the perovskite–SQ interface. These benefits lead to enhanced perovskite efficiency from 15.77 to 18.83% with the fill factor approaching 80%, which is among the highest efficiency reported for MAPbI3 solar cells fabricated in an ambient environment at 60% relative humidity (RH). Considerable retardation of perovskite device degradation was achieved, retaining 90% of initial efficiency when kept 600 h at 60 ± 5% RH.

Desolvation of lithium ions and diffusion of Li+ through the solid electrolyte interface (SEI) play an important role in determining the extreme fast-charging ability of graphite for electric vehicle (EV) application. For this reason, a novel aqueous borate type bio-based polymer with inherent Li ions was designed as an SEI forming binder for graphite. The low lying LUMO energy level enabled the preferential reduction of the binder prior to the degradation of the electrolyte or salt to form a thinner and highly conducting borate rich SEI. A robust boron rich SEI and a binder with inherent Li ions improved the kinetics with low activation energy for lithiation/desolvation (22.56 kJ/mol), lower SEI resistance, and a high Li+ diffusion coefficient across the graphite galleries (7.24 × 10–9 cm2 s–1). Anodic half-cells with the novel binder delivered a discharge capacity of 73 mAh/g at 10 C, which is three times higher than the those of the polyvinylidene fluoride (PVDF) and sodium carboxymethyl cellulose/polystyrene-polybutadiene rubber (CMC-SBR) counterparts, with a high capacity retention for more than 1000 cycles.

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Combined theoretical and experimental approaches using model squaraine dyes as a representative of NIR sensitizers have demonstrated the possibility for facile dye regeneration, with a very small driving force of 0.12 eV, from the most commonly used iodine based redox electrolytes.