Embedding a Diketopyrrolopyrrole-Based Cross-linking Interfacial Layer Enhances the Performance of Organic Photovoltaics

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/MoO/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-C-butyric acid methyl ester (PCBM) 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 PCBM, for efficient carrier transport. The power conversion efficiency (AM 1.5 G, 1000 W m) 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%).

Enhanced Device Performance and Stability of Organic Photovoltaics Incorporating a Star-Shaped Multifunctional Additive

“…The detailed process used methods reported previously (see the SI-Experimental Section). To explore the effect of DPPTPTA on the device performance, we fabricated the devices incorporating 0, 1, 3, 5, and 10 wt % DPPTPTA (weight percentage relative to PC 61 BM). Compared with PC 71 BM, PC 61 BM is cheaper and has a more spheroidal shape; the ellipsoidal PC 71 BM exhibits relatively complex molecular packing and cross-linking behavior and might induce more complex BHJ morphology .…”

The Twisted Benzo[ghi]‐Perylenetriimide Dimer as a 3D Electron Acceptor for Fullerene‐Free Organic Photovoltaics

“…Moreover, all BPTI‐based NFAs exhibited over 95 % emission quenching efficiency of PTB7‐Th (Figure b), indicating the efficient charge separation following the excitations of the donor and acceptors. The fabricated BHJ OPVs had an inverted structure of indium tin oxide (ITO)/ZnO(50 nm)/PTB7‐Th:BPTIs/MoO 3 (3 nm)/Ag (100 nm) . A optimal donor/acceptor ratio of 1:1 (w/w) was spin‐cast from chlorobenzene as processing solvent and an active layer with a thickness of approximately 90 nm was formed.…”

“…The fabricated BHJ OPVs had an inverted structure of indium tin oxide (ITO)/ZnO(50nm)/PTB7-Th:BPTIs/ MoO 3 (3 nm)/Ag (100 nm). [47,48] Ao ptimal donor/acceptor ratio of 1:1( w/w) was spin-cast from chlorobenzenea sp rocessing solventa nd an active layer with at hickness of approximately 90 nm was formed.…”

Simultaneous Passivation of Surface Vacancies and Enhancement in Charge Transfer Property of ZnO Electron Transport Layer for Inverted Organic Solar Cells

“…rGN played a dual role, and it not only passivated the ZnO surface and reduced the recombination rate and but also made better contact between the ZnO and the active layer, which leads to improved EQE of the solar cell. [63][64][65][66] In Figure 6b, the J sc value of 20.05 (AE0.51) mA cm À2 is the average value of ten fabricated devices. The J-V measurements were conducted using an light emitting diode (LED) solar simulator (Power intensity 100 mW cm À2 , wavelength range 400-1000 nm, Keithley HP2400 source meter).…”