Surface-Governed Photoredox Reactivity of CsPbBr₃ Quantum Dots

Area of Science:

• Colloidal quantum dots (CQDs)
• Photoredox catalysis
• Surface chemistry

Background:

• Surface chemistry is critical for CQDs in photoredox catalysis, balancing charge transfer, active site accessibility, and stability.
• Understanding surface ligand effects is key to controlling CQD catalytic performance.

Purpose of the Study:

• To investigate the role of surface ligand coverage on CsPbBr3 CQDs in photoredox catalysis.
• To differentiate between direct electron transfer and chemisorption pathways.
• To optimize CQD surface chemistry for enhanced catalytic activity.

Main Methods:

• Systematic variation of surface ligand coverage on CsPbBr3 CQDs.
• Monitoring reaction rates and product yields for C(sp3)-H brominations.
• Assessing CQD stability under varying surface conditions.

Main Results:

• Reduced surface ligand coverage significantly increased reaction rates for substrate adsorption-dependent reactions, such as C(sp3)-H brominations (up to 3-fold yield increase).
• This enhancement is attributed to improved activation of chemisorbed substrates, scaling with available surface sites.
• The approach enabled activation of more challenging chlorinated compounds, demonstrating tunable reactivity.

Conclusions:

• Surface ligand coverage is a critical parameter for controlling reactivity in CQD-based photoredox catalysis.
• Optimizing surface coverage allows for enhanced catalytic efficiency and substrate activation.
• This strategy provides a pathway for designing advanced CQD photocatalysts.