LAUSR

Abstract In this work, we present and support the positive influence of 1,8-diiodooctane (DIO) as processing additive for the fabrication of solution processed near infrared (NIR) organic photodiodes (OPDs) based on the spray-coated blend of [6,6]phenyl-C70-butyric acid methyl ester (PC70BM) and poly[(2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-diox-opyrrolo[3,4-c]pyrrole-1,4-diyl)-alt-([2,2’:5′,2″-terthioph-ene]-5,5″-diyl)] (PDPP3T). Transmission electron microscopy (TEM) analysis show that the use of DIO improves donor–acceptor interfaces in the bulk heterojunction (BHJ) layer. Besides the enhancement of electron/hole transport pathways that leads to higher efficiencies, it reduces significantly the roughness of spray coated layers. The External Quantum Efficiency (EQE) is increased up to 35% at 900 nm and the dark current is decreased one order of magnitude in comparison to the reference down to 20 nA/cm2 at -5 V. The OPD's detectivity is increased from 1.66 × 1011 Jones to 3.34 × 1012 Jones and the linearity response is improved. A comprehensive morphological and electro-optical characterization of the generated layers and devices is the main focus of this work.