Thickness dependent enhanced efficiency of polymer solar cells with gold nanorods embedded in the photoactive layer

In this work, the dependence of the enhancement in the efficiency of polymer solar cells incorporated with gold nanorods embedded in the photoactive layer on the photoactive layer thickness has been studied in detail. Synthesized toluene-based gold nanorods were introduced to devices by simply blending them with a solution of poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric-acid-methyl-ester. The photovoltaic parameters for devices made with two different thicknesses, 100 and 40 nm, of polymer:fullerene:nanorods films revealed that while the power conversion efficiency of the thin devices was enhanced by 27% due to the plasmonic effect induced by the presence of the gold nanorods in the film, its value was lowered in devices made with the thicker films. Comparison between thick/thin photoactive films' absorbance, morphologies and shunt resistances related such reduction in the performance to the high leakage current that resulted from quenching energy states in the photoactive film.