Visualizing Charge Transport and Nanoscale Electrochemistry by Hyperspectral Kelvin Probe Force Microscopy.
Liam CollinsRama K VasudevanAlp SehirliogluPublished in: ACS applied materials & interfaces (2020)
Charge-transport and electrochemical processes are heavily influenced by the local microstructure. Kelvin probe force microscopy (KPFM) is a widely used technique to map electrochemical potentials at the nanometer scale; however, it offers little information on local charge dynamics. Here, we implement a hyperspectral KPFM approach for spatially mapping bias-dependent charge dynamics in timescales ranging from the sub-millisecond to the second regime. As a proof of principle, we investigate the role mobile surface charges play in a three-unit-cell LaAlO3/SrTiO3 oxide heterostructure. We explore machine learning approaches to assist with visualization, pattern recognition, and interpretation of the information-rich data sets. Linear unmixing methods reveal hidden bias-dependent interfacial processes, most likely water splitting, which are essentially unnoticed by functional fitting of the dynamic response alone. Hyperspectral KPFM will be beneficial for investigating nanoscale charge transport and local reactivity in systems involving a possible combination of electronic, ionic, and electrochemical phenomena.
Keyphrases
- single molecule
- ionic liquid
- label free
- solar cells
- gold nanoparticles
- living cells
- machine learning
- high resolution
- molecularly imprinted
- atomic force microscopy
- single cell
- quantum dots
- high throughput
- optical coherence tomography
- health information
- stem cells
- gene expression
- big data
- artificial intelligence
- genome wide
- molecular dynamics simulations
- deep learning
- fluorescent probe
- simultaneous determination
- solid phase extraction