Bandgap Engineering of Halide Perovskite Nanocrystals for Maximizing Hole Transfer: Accessing the Marcus Inverted...

Area of Science:

• Materials Science
• Photocatalysis
• Nanotechnology

Background:

• Efficient charge transfer at semiconductor interfaces is crucial for photocatalysis.
• Band energy alignment between semiconductors and acceptor molecules dictates charge transfer kinetics.

Purpose of the Study:

• To systematically investigate hole transfer from perovskite nanocrystals (NCs) to acceptor molecules.
• To understand the influence of perovskite bandgap and driving force on charge transfer rates.
• To explore the role of reorganization energy in interfacial charge transfer.

Main Methods:

• Utilized p-phenylenediamine (PPD) and m-phenylenediamine (MPD) as probe molecules.
• Employed transient absorption and photoluminescence decay spectroscopy.
• Tuned perovskite NC bandgaps (0.94–1.74 V vs NHE) via halide composition (Cl:Br, Br:I ratios).

Main Results:

• Observed a nonlinear dependence of hole transfer rate constants on the driving force (-ΔG).
• Applied Marcus-electron transfer theory, revealing a reorganization energy of ~1 eV.
• Identified significant contributions from the oleylamine ligand shell and charged NC lattice to reorganization energy.

Conclusions:

• Interfacial charge transfer in perovskite NCs is strongly influenced by ligand shells and lattice structure.
• Bandgap engineering of perovskite NCs offers a pathway to maximize charge transfer yield.
• Findings provide insights for designing efficient perovskite-based photocatalysts.