Electron-hopping across dye-sensitized mesoporous NiO surfaces
Sina Wrede1, Lanlan He2, Gerrit Boschloo1
1Department of Chemistry-Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden. haining.tian@kemi.uu.se.
Physical Chemistry Chemical Physics : PCCP
|December 5, 2022
Summary
Investigating electron hopping in dye-sensitized NiO photocathodes revealed two pathways. Fast electron transport via NiO surface states dominates over dye-to-dye transfer, impacting recombination kinetics.
Area of Science:
- Materials Science
- Electrochemistry
- Photocatalysis
Background:
- Hole hopping in photoanodes is well-studied.
- Electron hopping in photocathodes lacks extensive research.
- Understanding charge transport is crucial for device efficiency.
Purpose of the Study:
- Investigate lateral electron hopping in dye-sensitized NiO photocathodes.
- Elucidate electron transfer dynamics between dyes and NiO surface states.
- Determine the dominant charge transport pathway.
Main Methods:
- Utilized temperature-dependent spectroelectrochemistry.
- Employed computational simulations.
- Studied an organic p-type dye (TIP) with donor-linker-acceptor design.
Main Results:
- Identified two electron hopping pathways: dye-to-dye (10^5 s^-1) and NiO surface states (10^7 s^-1).
- Electron hopping via NiO surface states precedes dye-to-dye hopping.
- NiO surface state reduction is necessary before dye-to-dye transfer.
Conclusions:
- Fast electron transport through NiO surface states likely dominates recombination kinetics.
- Intermolecular charge transport between dyes is less relevant in this system.
- Findings contrast with sensitized photoanodes where charge transfer impacts recombination.
