Electronic structures of triblock copolymers

A tight-binding calculation to describe triblock copolymers xPA/yPPP/xPA or xPPP/yPA/xPPP is presented. The dependence of the band gap of triblock copolymers on the interfacial couplings or on the composite segment lengths is studied. For xPPP/yPA/xPPP structures, the band gap varies with PA segment length over a wide range, from 1.32eV to 2.74eV. For xPA/yPPP/xPA structures, the band gap is invariant with PPP segment length.