Polyacid-Modulated Carrier Dynamic Behavior at the Interface of 0D/2D Heterojunctions

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Chemistry

Background:

• Polyoxometalates (POMs) and 2D materials form heterojunctions with significant photoelectric and catalytic potential.
• The precise mechanisms by which POMs influence heterojunction photoelectric properties remain largely unexplored.

Purpose of the Study:

• To investigate the photoexcited carrier dynamics in heterojunctions formed by two distinct POMs (Keggin-type H3PW12O40 and Lindqvist-type H2W6O19) integrated onto g-C3N4 monolayers.
• To elucidate the role of POM type in regulating band alignment and charge carrier behavior within 0D/2D heterojunctions.

Main Methods:

• Construction of H3PW12O40/g-C3N4 and H2W6O19/g-C3N4 heterojunctions.
• Ab initio calculations combined with nonadiabatic molecular dynamics (NAMD) simulations to explore photoexcited carrier dynamics.

Main Results:

• In H3PW12O40/g-C3N4, electron and hole relaxation occurred within 583 fs and 760 fs, respectively, with recombination at 342 fs, indicative of Z-type heterojunction behavior.
• The H2W6O19/g-C3N4 heterojunction displayed characteristics of a type II heterojunction, featuring a prolonged photogenerated carrier lifetime of 652 fs.
• Demonstrated tunable band alignment by altering the POM type, significantly impacting hot electron dynamics.

Conclusions:

• The type of polyoxometalate integrated onto 2D materials critically influences heterojunction band alignment and carrier dynamics.
• Findings provide fundamental insights into the mechanisms governing photoelectric properties in POM-based 0D/2D heterojunctions.
• Offers guidance for the rational design of advanced heterojunctions for optimized photoelectric and catalytic applications.