Nanoscale TiO2 Protection Layer Enhances the Built-In Field and Charge Separation Performance of GaP Photoelectrodes.
Zihao XuBingya HouFengyi ZhaoZhi CaiHaotian ShiYawei LiuCraig L HillDjamaladdin G MusaevMatthew MecklenburgStephen B CroninTianquan LianPublished in: Nano letters (2021)
Nanoscale oxide layer protected semiconductor photoelectrodes show enhanced stability and performance for solar fuels generation, although the mechanism for the performance enhancement remains unclear due to a lack of understanding of the microscopic interfacial field and its effects. Here, we directly probe the interfacial fields at p-GaP electrodes protected by n-TiO2 and its effect on charge carriers by transient reflectance spectroscopy. Increasing the TiO2 layer thickness from 0 to 35 nm increases the field in the GaP depletion region, enhancing the rate and efficiency of interfacial electron transfer from the GaP to TiO2 on the ps time scale as well as retarding interfacial recombination on the microsecond time scale. This study demonstrates a general method for providing a microscopic view of the photogenerated charge carrier's pathway and loss mechanisms from the bulk of the electrode to the long-lived separated charge at the interface that ultimately drives the photoelectrochemical reactions.
Keyphrases
- electron transfer
- quantum dots
- visible light
- molecular dynamics simulations
- ionic liquid
- solar cells
- perovskite solar cells
- sensitive detection
- atomic force microscopy
- solid state
- photodynamic therapy
- dna damage
- optical coherence tomography
- carbon nanotubes
- oxidative stress
- gold nanoparticles
- dna repair
- single molecule
- fluorescent probe