Anomalous Dependence of Photocarrier Recombination Time on the Polaron Density of TiO2(110).
J Phys Chem Lett
; 14(37): 8312-8319, 2023 Sep 21.
Article
em En
| MEDLINE
| ID: mdl-37683279
ABSTRACT
Polarons play a crucial role in energy conversion, but the microscopic mechanism remains unclear since they are susceptible to local atomic structures. Here, by employing ab initio nonadiabatic dynamic simulations, we investigate electron-hole (e-h) nonradiative recombination at the rutile TiO2(110) surface with varied amounts of oxygen vacancies (Vo). The isolated Vo facilitates e-h recombination through forming polarons compared to that in the defect-free surface. However, aggregated Vo forming clusters induce an order-of-magnitude acceleration of polaron diffusion by enhancing phonon excitations, which blocks the defect-mediated recombination and thus prolongs the photocarrier lifetime. We find that photoelectrons are driven to migrate toward the top surface due to polaron formation. Our results show the many-body effects of defects and polaron effects on determining the overall recombination rate, which has been ignored in the Shockley-Read-Hall model. The findings explain the controversial experimental observations and suggest that engineering Vo aggregation would instead improve photocatalysis efficiencies in polaronic materials.
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1
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article