Chemical mist deposition of organic for efficient front- and back-PEDOT:PSS/crystalline Si heterojunction solar cells

Abstract

We have investigated an n-type crystalline Si (n-Si) heterojunction solar cell with organic conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on a plane and isotropically textured n-Si substrate by using chemical mist deposition (CMD). The PEDOT:PSS layer was deposited uniformly on isotropically textured n-Si with the increased passivation of surface defects of n-Si and stronger adhesion rather than the spin-coated film by adjusting deposition parameters. The power conversion efficiency increased from 12.5% on plane n-Si to 16%-18.2% for both CMD coated front- and back-PEDOT:PSS/n-Si junction solar cells on the 2 × 2 cm2-sized isotropically textured substrate by combining with a 1-2-nm-thick Ba(OH)2 by CMD as a hole-blocking layer at the Al/n-Si interface. These findings originate from the increased passivation of surface dangling bonds of isotropically textured n-Si, resulting in strong inversion of the n-Si surface to p-type Si by the polymer.