Optimization of organic solar cells with thin film Au as anode

Optical transmittance and conductivity for thin metallic films, such as Au, are two inversely related and extremely important parameters for its application in organic photovoltaics as the front electrode. We report our findings on how these parameters have been optimized to attain maximum possible efficiencies by fabricating organic solar cells with thin Au film anodes of differing optical transmittances and consequently due to scaling at the nanolevel, varying electrical conductivities. There was an extraordinary improvement in the overall solar cell efficiency (to the order of 49%) when the Au thin film transmittance was increased from 38% to 54%. Surface morphologies of these thin films also have an effect on the critical parameters including, Voc, Jsc and FF.

Graphical abstractThe efficiency of organic photovoltaic devices increases with the increase in transmittance of the thin Au film anode. However, after a certain transmittance the sheet resistance of the anode becomes very high and the efficiency starts to decrease.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Organic Photovoltaics were fabricated on thin Au films of varying transmittances (38–66%). ► All the critical parameters, namely the Voc, Jsc and FF change with the change in transmittance and sheet resistance. ► Increase in transmittance increases the efficiency, reaches a maximum of 1.83% and then decreases. ► Surface morphology of the Au films influences the FF to a great extent.