spectroscopy of the device in OFG has been carried out. Device in OFG was prepared by drop casting the active material (EV+PEO) on a pre-fabricated electrode system where two gold electrodes are a few microns apart. A drop of prepared sample in the gap completes electrical circuit and device will start working like electrochemical cell. Top view of the finished device is shown in Fig. 5(a) without and with bias applied. The polarity scheme of the power supply to give bias is shown in Fig. 5(b), which shows the cross-sectional schematic of the device. A color change on electrode E1 as a result of –ve bias on this electrode can be seen which is similar to the bias induced colour change in Fig. 2 . This can be appreciated by comparing point X and Y in Fig. 5(a). Raman spectra has been recorded from points X,Y and Z (Fig. 5(a)) to compare the effect of bias on the present chemical species in the device. These points have been chosen for Raman measurements so that a comparison can be done between Raman signal from a virgin device (point X), negative terminal (point Y, where reduction is possible) and positive terminal (point 