Photoinduced electron transfer across the polymer-capped CsPbBr3 interface in a polar medium

Abstract

In-situ polymer capping of cesium lead bromide (CsPbBr3) nanocrystals with polymethyl acrylate is an effective approach to improve the colloidal stability in the polar medium and thus extends their use in photocatalysis. The photoinduced electron transfer properties of polymethyl acrylate (PMA)-capped CsPbBr3 nanocrystals have been probed using surface-bound viologen molecules with different alkyl chains as electron acceptors. The apparent association constant ( K app) obtained for the binding of viologen molecules with PMA-capped CsPbBr3 was 2.3 × 107 M−1, which is an order of magnitude greater than that obtained with oleic acid/oleylamine-capped CsPbBr3. Although the length of the alkyl chain of the viologen molecule did not show any impact on the electron transfer rate constant, it influenced the charge separation efficiency and net electron transfer quantum yield. Viologen moieties with a shorter alkyl chain length exhibited a charge separation efficiency of 72% compared with 50% for the longer chain alkyl chain length viologens. Implications of polymer-capped CsPbBr3 perovskite nanocrystals for carrying out photocatalytic reduction in the polar medium are discussed.

Directional Electron Transfer across In2S3/ZnS-Embedded Photocatalytic Membranes

“…Another aspect is the overall back electron-transfer process. As discussed earlier, the back electron transfer plays an important role in dictating the yield of steady-state concentration of the reduced product …”

“…The appearance of MV +• within a few picoseconds after laser pulse excitation confirms the ultrafast electron transfer from excited In 2 S 3 /ZnS to MV 2+ . Similar fast formation of MV +• has been observed for electron transfer in AgInS 2 and CsPbBr 3 nanocrystal suspensions. , The electron-transfer product (MV +• ) remains stable and exhibits little decay in the 30 ns window as shown in Figure D. The long-lived electron-transfer product (MV +• ) enables accumulation over time as demonstrated in the steady-state photolysis (vide supra).…”

“…As discussed earlier, the back electron transfer plays an important role in dictating the yield of steady-state concentration of the reduced product. 39 Tracking Forward and Back Electron Transfer under Steady-State Irradiation. We tracked the formation of MV +• generated in the photocatalytic membrane during the steadystate photoirradiation and its decay upon stopping the illumination by recording the absorption spectra of the film at different time intervals.…”

Enhancing Photocatalytic Attributes of Perovskite Nanocrystals in Aqueous Media via Ligand Engineering

“…Recent reports have indicated that polymer overlayers can support long-lived charge carriers in photovoltaic devices . Additionally, the photogenerated charge transfer properties of polymer-capped perovskite NCs have been explored for use as photocatalysts in different solvents. − Moreover, the significance of such photocatalyzed polymerization processes for additive manufacturing in three-dimensional printing applications should not be underestimated. , Consequently, the exploration of charge separation and transport properties in acrylamide-polymer-encapsulated CsPbBr 3 /NKE-12 NCs holds promising potential.…”

“…Early photophysical investigations have delved into the charge transfer dynamics of LHPs in nonpolar media when in the presence of electron or hole acceptors. − More recently, a few studies have revealed the photoactivity of LHPs in organic media, encompassing dye degradation, organic synthesis via C–H bond activation, C–C and C–P bond formation, − hydrogen evolution, , and CO 2 reduction to chemical fuels. − Some researchers have employed perovskite-polymer blends or grafting (e.g., polystyrene, poly­(methyl methacrylate)) to enhance colloidal stability, leading to improved applications in light-emitting and display technologies. − However, the primary hurdle to employing LHP nanocrystals (NCs) as photocatalysts has been their instability in an aqueous medium.…”