phase-kick Electrostatic Force Microscopy (pk-EFM): Atomic Force Microscopy method for probing solar cell materials
- 详细技术说明
- Our new method, phase-kickElectrostatic Force Microscopy (pk-EFM), significantly improves the timeresolution of electric force microscopy (EFM), enabling the rapid acquisitionof photocapacitance transients in solar cell films.
- *Abstract
-
Technology Overview
We offer a new atomic force microscopy (AFM) techniquesuitable for the studying photo-generated charges in photovoltaic films byobserving charge-generation transients on relevant timescales and spatialresolutions. This invention opens up exciting possibilities for studying chargecarrier generation and recombination at nanosecond temporal resolutions andnanometer spatial resolutions in a wide range of device-relevant organicphoto-voltaic films.
This technique has the potentialto overcome the challenge of obtaining nanosecond time-resolutions; theultimate time resolution of this technique is limited only by the ability tomodulate the tip voltage and laser pulse, which can be as fast as picoseconds. Through the use of an oscillating chargedmicro-cantilever, we record photocapacitance indirectly. This is done bymeasuring the change in the phase of the oscillation of the cantilever as afunction of the time-delay between the precisely synchronized voltage pulsesand light pulses.
In our proof-of-concept wedemonstrate, in an organic donor-acceptor blend, the ability of this indirect“phase-kick” technique to enable the reconstruction of the fullphotocapacitance transient, while sidestepping detector noise and demodulatorbandwidth limitations to the achievable time resolution. We further demonstratethe method’s time resolution in a control experiment in which we measure atip-charging time of 35 ns.
PotentialApplications
- AFM/EFM study of fundamental processes, at thesingle-molecule or single-domain level including:
- Photo-inducedelectron transfer
- Chargerecombination
- Chargetrapping
- Photocatalysis
- Ferroelectricswitching
Advantages
- Potential for sub-nanosecond time resolution
- Nanometer-scale spatial resolution
- Allows study of materials prepared on electrodes
- Records the full photocapacitance transient
- pk-EFM signal and time-resolution are well-understood and matchtheory across a range of time scales
- AFM/EFM study of fundamental processes, at thesingle-molecule or single-domain level including:
- *Licensing
- Patrick Govangpjg26@cornell.edu1-607-254-2330
- 其他
-
Publications
- Ryan P. Dwyer, Sarah R. Nathan, John A. Marohn. “Microsecond photocapacitance transientsobserved using a charged microcantilever as a gated mechanical integrator”;Science Advances, 09 Jun 2017: Vol.3, no. 6. DOI:10.1126/sciadv.1602951
- “Group's measuringtool probes solar-cell materials” CornellChronicle, June 2017. http://news.cornell.edu/stories/2017/06/groups-measuring-tool-probes-solar-cell-materials
- 国家/地区
- 美国
