Synthesis of diblock copolymer consisting of poly(4-butyltriphenylamine) and morphological control in photovoltaic application

Abstract

The diblock copolymer PTPA-b-PS consisting of poly(4-butyltripheneylamine) (PTPA) and polystyrene was prepared by atom transfer radical polymerization followed by C-N coupling polymerization. Three types of block copolymers with different contents of polystyrene segment were prepared. The formation of block copolymer was confirmed by 1H NMR spectra and gel permeation chromatography (GPC) profiles. Time of flight (TOF) measurement revealed that the block copolymer showed higher hole mobility up to 1.3 × 10 -4 cm 2/Vs compared with PTPA homopolymer. The surface morphology of block copolymer films blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was investigated by Atomic force microscopy (AFM). Introduction of polystyrene segment provided microphase-separated structures with domain sizes of around 20 nm. The photovoltaic device based on PTPA-b-PS, PTPA, and PCBM exhibited higher efficiency than that of homopolymer blend system. © 2011 by the authors.