Influence of alkyl chain length of boronic acid self-assembled monolayers on indium tin oxide and their organic solar cell performance

Abstract

We report boronic acid based self-assembled monolayer molecules with three different alkyl chain lengths to treated ITO surfaces to improvement of photovoltaic device parameters in P3HT:PCBM based organic solar cells. Herein, C-8-BA, C-10-BA, and C-12-BA were successfully formed on ITO surfaces. It was determined that surface morphology and electrical characteristics of ITO layer were improved and the charge transport properties were enhanced by using of alkyl-BA SAMs. The band gap transitions were calculated from UV-Vis spectra and the results showed that alkyl-BA SAMs treatment could mediate the energy band gap overlapping, thus improve charge transport properties. A power conversion efficiency at a yield of 3.4% was achieved by C-12-BA SAM treatment, thanks to reduced series resistance and charge recombination. The results revealed that the treatment of ITO with alkyl-BA SAMs, as a new class of interfacial modifier, is a versatile technique to improve photovoltaic device performance of organic solar cells.