Investigation of the effect of diiodooctane on the morphology and performance of PTB7/PC71BM solar cells

Organic photovoltaics have been intensively investigated in recent years for generation of affordable, clean, and renewable energy due to their low-cost fabrication of large-area devices, lightweight, mechanical flexibility, and easy tunability of chemical properties of the polymer materials. Thieno[3,4-b]thiophene and benzodithiophene solar cells were fabricated, characterized and the performance of the solar cells was studied and compared with each other in the different ratios of diiodooctane. Atomic force microscopy was used to study the morphological changes in solar cells. The current density and voltage characteristics of photovoltaic cells were measured under the illumination of simulated solar light. PTB7/PC71BM solar cell enhanced the power conversion efficiency to 2.86% with 0.5% diiodooctane from 1.55% without diiodooctane. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim