Improvement in efficiency of polymer bulk-heterojunction solar cells using modified PEDOT:PSS buffer layers with alcohol derivatives

We demonstrated that the use of modified poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) buffer layers with alcohol derivatives between an electrode and a photoactive layer can lead to the improvement in the efficiency of polymer bulk-heterojunction solar cells. Polymer solar cells containing modified PEDOT:PSS layers show significant improvement in power conversion efficiency by up to >59% when compared with a device containing only pristine PEDOT:PSS layers. Conformational and morphological changes in the PEDOT:PSS buffer layer corresponding to the dopant polarity and concentration have strong correlations with the surface roughness and arrangement of PEDOTand PSS, which could explain the behaviors of the polymer bulk-heterojunction solar cells with the modified PEDOT:PSS layers.