Green-solvent-processed hybrid solar cells based on donor–acceptor conjugated polyelectrolyte

Abstract

In this work, a quaternary ammonium side chain modified conjugated polyelectrolyte PFBTBr, with excellent solubility in nonaromatic and nonhalogenated solvents, was designed and synthesized as the donor material for the green-solvent-processed hybrid solar cells (HSCs). By introducing the donor–acceptor structure, PFBTBr shows a lower lying highest occupied molecular orbital (HOMO) level and a broad absorption from 300 to 700 nm. Incorporating the water soluble CdTe nanocrystals (NCs) as acceptor, the green-solvent-processed HSCs based on conjugated polyelectrolyte and inorganic NCs were fabricated. Through the active layer optimization, a well blended donor/acceptor active layer with continuous electron/hole transport pathway and smoother surface was achieved. As a result, a photovoltaic efficiency of 3.67% was realized. After the further interfacial modification and chloride treatment, the power conversion efficiency of the green-solvent-processed HSCs was improved to 5.03% with the maximum external quantum efficiency value of 87.01% at 400 nm under the AM 1.5 G 100 mW cm⁻² illumination.