Document Type

Journal Article

Department/Unit

Department of Physics

Title

Impact of solvent additive on carrier transport in polymer: Fullerene bulk heterojunction photovoltaic cells

Abstract

The effects of a solvent additive, 1,8-diiodooctane (DIO), on both hole and electron transport are investigated in a state-of-the-art bulk-heterojunction (BHJ) system, namely PTB7:PC71BM. For a polymer:fullerene weight ratio of 1:1.5, the electron mobility in the blend film increases by two orders of magnitude with the DIO concentration while almost no change is found in the hole mobility. For lower DIO concentrations, the electron mobility is suppressed because of large, but poorly connected PC71BM domains. For higher concentrations of DIO, the electron mobility is improved progressively and the hole mobility becomes the limiting factor. Between 1 and 5 vol%, the electron and hole mobilities are balanced. Using the Gaussian disorder model (GDM), we found that the DIO concentration modifies fundamentally the average hopping distances of the electrons. In addition, there exist alternative donor–acceptor ratios to achieve optimized PTB7:PC71BM based solar cells. It is demonstrated that the fullerene content of the BHJ film can be significantly reduced from 1:1.5 to 1:1 while the optimized performance can still be preserved.

Publication Year

2015

Journal Title

Advanced Materials Interfaces

Volume number

2

Issue number

12

Publisher

Wiley

Referreed

1

DOI

10.1002/admi.201500166

Link to Publisher’s Edition

http://dx.doi.org/10.1002/admi.201500166

Keywords

admittance spectroscopy, bulk heterojunction, carrier transport, photovoltaics, solvent additives

ISSN (electronic)

21967350

This document is currently not available here.

Share

COinS