Using easily prepared carbon nanodots to improve hole transport capacity of perovskite solar cells

Abstract

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is the most widely-used transparent anode material of commercialization. However, the partially bonding between PSS and PEDOT greatly decreases the structural and electronic homogeneity of PEDOT:PSS system. In view of their molecular structure and functional groups, a S, N co-doped carbon nanodots (CNDs) was developed as ameliorant to prepare PEDOT:PSS:CNDs hole transport layer. The uncombined S double bond introduces more microcosmic interstice inside CNDs, accompanying with many N-rich amino on the surface. This highly reactive products can band the redundant PSS and remove the insulating component from PEDOT:PSS mixture, leading to the conductivity and structural homogeneity improvement. The hole-transport capability of PEDOT:PSS:CNDs is systematically investigated in inverted planar hetero-junction (PHJ) perovskite solar cells (PSCs) fabricated in air, and an optimized power conversion efficiency (PCE) of 18.03% was achieved, which is superior to PEDOT:PSS based PSCs produced under atmospheric. This work offers a new strategy to improve the charge transfer capability of PEDOT:PSS in PSCs.