Polymer, Vol.55, No.6, 1507-1513, 2014
Performance enhancement of block-copolymer solar cells through tapering the donor-acceptor interface: A multiscale Study
Tapered block copolymers offer an exciting opportunity to tailor the interfacial region between different components by conserving their phase-separated mesoscale structure, which enable the generation of polymer systems with the desired spatio-dynamic properties. Here, we explore their usefulness for optimizing the photovoltaic performance of polymer bulk heterojunctions. To this end, we apply a recently developed particle-based multiscale solar-cell algorithm and investigate the effect of random tapering at the chemical junctions between the electron-donor- (D) and electron-acceptor- (A) blocks on the photovoltaic properties of various lamellar-like polyfluorene-based block-copolymer systems. Our simulation results reveal that introducing a tapered middle block with optimal length leads to a significant increase of the exciton dissociation efficiency, but deteriorates the charge transport efficiency only moderately. This results in a gain of the internal quantum efficiency from 25 up to 39% by increasing the thickness of the active layer of the solar cell from 10 up to 50 nm in direction to the DA interface. (c) 2014 Elsevier Ltd. All rights reserved.
Keywords:Photovoltaic performance of polymer bulk;heterojunctions;Tapering of donor-acceptor interface;Multiscale modeling study