Energy Versus Electron Transfer: Managing Excited-State Interactions in Perovskite Nanocrystal–Molecular Hybrids

Abstract

Energy and electron transfer processes in light harvesting assemblies dictate the outcome of the overall light energy conversion process. Halide perovskite nanocrystals such as CsPbBr3 with relatively high emission yield and strong light absorption can transfer singlet and triplet energy to surface-bound acceptor molecules. They can also induce photocatalytic reduction and oxidation by selectively transferring electrons and holes across the nanocrystal interface. This perspective discusses key factors dictating these excited-state pathways in perovskite nanocrystals and the fundamental differences between energy and electron transfer processes. Spectroscopic methods to decipher between these complex photoinduced pathways are presented. A basic understanding of the fundamental differences between the two excited deactivation processes (charge and energy transfer) and ways to modulate them should enable design of more efficient light harvesting assemblies with semiconductor and molecular systems.

Photocatalytic Degradation of Alkyl Halide Molecules Promoted by CsPbBr3 Perovskite Quantum Dots

“…These results are comparable to those measured for the pristine OLA/OA-PQDs. They confirm that introducing more complex and high affinity surface coating of the nanocrystals does not interfere with the photocatalytic properties of the PQDs. , …”

“…They confirm that introducing more complex and high affinity surface coating of the nanocrystals does not interfere with the photocatalytic properties of the PQDs. 39,40 We also carried out a few experiments to probe additional experimental conditions. In the first, we tested the effects of whether stirring the dispersion during irradiation would affect the progress of absorption and PL blue shifting toward saturation.…”

Tunable Luminescence and Enhanced Polar Solvent Resistance of Perovskite Nanocrystals Achieved by Surface-Initiated Photopolymerization

“…Comparing to literature-reported grafting-onto method that utilized coiled chains which occupied more space, in situ growing polymers from surface, that is, “grafting-from”, usually achieved higher grafting density . Taking advantages of the photocatalytic properties − of PNCs, our group recently reported an in situ photocatalyzed radical polymerization approach to grow protective polymers from the PNCs, in which PNCs functioned as both the photocatalysts and substrates for the polymer growth, through the photoinduced-electron-transfer reversible addition–fragmentation chain transfer (PET-RAFT) radical polymerization technique , under mild conditions. The polymer-stabilized PNC could be individually dispersed in various nonpolar and polar organic solvents, with improved colloidal stability and retained fluorescence properties.…”

Amine-Free Synthetic Route: An Emerging Approach to Making High-Quality Perovskite Nanocrystals for Futuristic Applications

“…can be used to mimic excited -state energy transfer processes, offering a new avenue for the production of stable photovoltaic devices. 73 Sensitization of singlet fission molecules such as acenes or pyrenes, which generate multiexcitons, can also be performed by amine-free PNCs, keeping long-term stability in mind. Through these continuing efforts, this exciting field of perovskite nanocrystals will attain a state of maturity that will widen our understanding of structure−property relationships in the nanodomain.…”

“…As the amine-free samples show higher stabilities in ambient conditions, amine-free PNC–chromophore couples (such as rhodamine B, crystal violet, etc.) can be used to mimic excited -state energy transfer processes, offering a new avenue for the production of stable photovoltaic devices . Sensitization of singlet fission molecules such as acenes or pyrenes, which generate multiexcitons, can also be performed by amine-free PNCs, keeping long-term stability in mind.…”