| AVS 64th International Symposium & Exhibition | |
| Scanning Probe Microscopy Focus Topic | Tuesday Sessions |
| Session SP+AS+MI+NS+SS-TuA |
| Session: | Probe-Sample Interactions |
| Presenter: | Liam Collins, Oak Ridge National Laboratory |
| Authors: | L. Collins, Oak Ridge National Laboratory S. Jesse, Oak Ridge National Laboratory S.V. Kalinin, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Kelvin probe force microscopy (KPFM) is crucial technique for the joint investigations of structural, electronic, and electrochemical functionality on materials ranging from ferroelectrics, and photovoltaics, to battery and fuel cell devices. While KPFM has shown extraordinary success for quantification of equilibrium or quasistatic functionalities, this level of information is not sufficient for describing electroactive materials or devices involving fast (< ms) relaxation processes. Practically, the detection methodologies adopted in classical KPFM limit the temporal resolution of the measurement (e.g. ~1-10 MHz photodetector stream is down sampled to a single readout of surface potential per pixel).
In this presentation General Acquisition mode (G-Mode) KPFM[1-3] will be introduced. It will be shown that by harnessing big data acquisition and analytics, it is possible to extract dynamic information on the local electrochemical processes with nanometer spatial and microsecond time resolution. Furthermore, the G-Mode KPFM approach is immediately implementable on all AFM platform, allows capture of numerous channels of information simultaneously (e.g. capacitive and potential channels), as well as providing increased flexibility in terms of data exploration across frequency, time, space, and noise domains.
Finally we harness these imaging capabilities to explore non-linear ionic transport in organic-inorganic halide perovskites. We will present imaging of spatio-temporal charge dynamics at the perovskite/electrode interface with <20 µs time resolution and ~10s nm spatial resolution. As will be outlined, based on our observations, we determine that the transport behavior of these materials is considerably more complex than previously argued.
[1] Collins, Liam, et al. "Multifrequency spectrum analysis using fully digital G Mode-Kelvin probe force microscopy." Nanotechnology 27.10 (2016): 105706.
[2] Collins, Liam, et al. "Full data acquisition in Kelvin Probe Force Microscopy: Mapping dynamic electric phenomena in real space." Scientific reports 6 (2016): 30557.
[3] Collins, Liam, et al. "Breaking the Time Barrier in Kelvin Probe Force Microscopy: Fast Free Force Reconstruction Using the G-Mode Platform." ACS nano (2017).