Tailor-made, custom-designed experimental methods to probe characteristic responses, time scales and length scales is pursued routinely. For example: we have come up with imaging methods to examine the heterogeneity in photoconducting polymer blends from 10 nm to several micron length scales. The notable thing is that we have the capability to zoom in on a stationery sample from confocal microscopy length scales to Atomic Force Microscope scales. This utilizes a combination of tips: including glass aperture tips for near field access and convention AFM tips. So if the sample has contrast features arising from optical/dielectric/topological/…. at these length scales, we get interested and analyze and see if there are correlations with bulk properties
We also extensively use noise measurements to probe the fluctuations in electrical transport which are inherent in these disordered systems. The novelty of this approach is that we are able to carry out noise measurements under constant photoexcitations. The fluctuations in the current with steady state of pumping carriers in the system directly reveals the trap kinetics, and importantly it reveals the condition of a photovoltaic module.
We carry out switching studies to examine the speed and the limitations of Field effect transistors over a frequency range extending up to100 MHz. Yes! organic FETs have response beyond 1 MHz, we are now able to operate these FETs and make basic circuits in the MHz regime.
