Embedding a Diketopyrrolopyrrole-Based Cross-linking Interfacial Layer Enhances the Performance of Organic Photovoltaics
Journal
ACS Applied Materials and Interfaces
Journal Volume
10
Journal Issue
10
Pages
8885-8892
Date Issued
2018
Author(s)
Abstract
In this study, we prepared DPPBTDA, a diketopyrrolopyrrole-based small molecule presenting a terminal cross-linkable azido group, as a cathode modifying layer for organic photovoltaics (OPVs) having the inverted device structure glass/indium tin oxide/zinc oxide (ZnO) with or without the interfacial layer (IFL)/active layer/MoO3/Ag. The active layer comprising a blend of poly[4,8-bis(5-(2-ethylhexyl)thien-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene)-2-carboxylate-2,6-diyl] (PTB7-Th) as the electron donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the electron acceptor. Atomic force microscopy, space-charge-limited current mobility, surface energy, electron spectroscopy for chemical analysis depth profile, ultraviolet photoelectron spectroscopy analysis, and OPV performance data revealed that the surface status of ZnO changed after inserting the DPPBTDA/PCBM hybrid IFL and induced an optimized blend morphology, having a preferred gradient distribution of the conjugated polymer and PC71BM, for efficient carrier transport. The power conversion efficiency (AM 1.5 G, 1000 W m-2) of the device incorporating the hybrid IFL increased to 9.4 ± 0.11% from 8.5 ± 0.15% for the preoptimized PTB7-Th/PCBM device (primarily because of an enhancement in the fill factor from 68.7 ± 1.1 to 72.1 ± 0.8%). © 2018 American Chemical Society.
Subjects
cross-linking; fill factor; Interfacial layer; morphology; organic photovoltaic
SDGs
Other Subjects
Atomic force microscopy; Blending; Butyric acid; Carboxylation; Chemical analysis; Electron spectroscopy; II-VI semiconductors; Morphology; Organic polymers; Tin compounds; Tin oxides; Ultraviolet photoelectron spectroscopy; Zinc oxide; Electron spectroscopy for chemical analysis; Fill factor; Gradient distributions; Interfacial layer; Inverted device structures; Organic photovoltaics; Power conversion efficiencies; Space charge limited currents; Conjugated polymers
Type
journal article