Solution-Processed Diketopyrrolopyrrole-Containing Small-Molecule Organic Solar Cells with 7.0% Efficiency: In-Depth Investigation on the Effects of Structure Modification and Solvent Vapor Annealing

Wang, Jinliang; Wu, Zhuo; Miao, Jingsheng; Liu, Kaikai; Chang, Zhengfeng; Zhang, Rubo; Wu, Hongbin; Cao, Yong

doi:10.1021/acs.chemmater.5b00848

Cited by 108 publications

(52 citation statements)

References 98 publications

(128 reference statements)

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“…While the effect of SVA on the device performance of polymer based BHJs was investigated in the late 2000s – early 2010s for a few polymer systems with limited success [15–18], the device performance of a number of small molecule based BHJs has been shown to significantly benefit from SVA. [9, 10, 19–27] Like the use of processing additives (e.g. 1,8-diiodooctane, DIO) for morphology control in polymeric semiconductors, SVA has a low-thermal budget and therefore is attractive for R2R-processing on flexible substrates with low glass transition temperatures.…”

Section: Introductionmentioning

confidence: 99%

Film morphology evolution during solvent vapor annealing of highly efficient small molecule donor/acceptor blends

Engmann

Herzing

et al. 2016

J. Mater. Chem. A

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Solution-processable small molecule photovoltaics based on the novel molecular donor, benzodithiophene terthiophene rhodanine (BTR), recently have shown maximum power conversion efficiencies above 8 % for active layer thicknesses up to 400 nm, using post process solvent vapor annealing (SVA) with tetrahydrofuran (THF). Here we report an in-situ study on the morphology evolution during SVA using the moderate solvent THF and the good solvent chloroform (CF). The combination of real-time grazing incidence X-ray diffraction (GIXD) and grazing incidence small angle X-ray scattering (GISAXS) allows us to draw a complete picture of the evolution of crystallinity and phase purity during post process annealing. We find that the relative crystallinity compared to the as-cast films is only modestly affected by SVA and solvent choice. However, both the phase purity and the characteristic domain sizes within the film vary significantly and are controlled by the solvent quality as well as exposure time. Using THF, films with high phase purity and desirable characteristic length scales of about 30 nm can be achieved, while the use of CF rapidly leads to excessive film coarsening and less preferable domain sizes on the order of 60 nm, too large for optimized charge separation.

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Section: Introductionmentioning

confidence: 99%

Film morphology evolution during solvent vapor annealing of highly efficient small molecule donor/acceptor blends

Engmann

Herzing

et al. 2016

J. Mater. Chem. A

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“…The thin-film UV-vis absorption spectra of SM1-3 are superimposed in Figure 1a, and the solution (in CHCl3) and thin-film spectra for each SM system are overlaid in Figure S1a 25,[54][55] The absence of long-wavelength absorption shoulders in the solution spectra of SM1-3 indicates that the molecules are not subject to π-aggregation at the concentration of this experiment (1x10 -5 M). In thin films (Fig.…”

Section: Design Synthesis and Materials Propertiesmentioning

confidence: 99%

Solvent Annealing Effects in Dithieno[3,2-b:2′,3′-d]pyrrole–5,6-Difluorobenzo[c][1,2,5]thiadiazole Small Molecule Donors for Bulk-Heterojunction Solar Cells

et al. 2016

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Low-bandgap small molecule (SM) donors that can be solution-processed with fullerene acceptors (e.g. PC61/71BM) are proving particularly promising in bulk-heterojunction (BHJ) solar cells. Compared to their π-conjugated polymer counterparts, SM donors are well defined (monodispersed) and more synthetically modular -with relatively wide ranges of bandgaps achievable in stepwise couplings of various donor and acceptor motifs. However, the optimization of SM-fullerene morphologies and BHJ device efficiencies relies more specifically on the use of processing additives, post-processing thermal or solvent vapor annealing (SVA) approaches, and achieving adequate interpenetrating networks and structural order in BHJ thin films can be challenging. In this report, we examine the correlated effects of molecular structure and post-processing SVA on the BHJ solar cell performance of a set of π-extended SM donors composed of dithieno[3,2-b:2',3'-d]pyrrole (DTP) and 5,6-difluorobenzo[c][1,2,5]thiadiazole ([2F]BT) units. In these systems (SM1-3), the introduction of additional alkyl substituents and unsubstituted thiophene rings on the peripheral unit groups critically impacts the effects of SVA steps on BHJ solar cell efficiency. We show that the more π-extended and alkyl-substituted analogue SM3 stands out -with BHJ device efficiencies of ca. 6% obtained from SVA with CS2-while SVA-treated SM3-based active layers also show the most favorable ordering and carrier mobility patterns. However, unlike numbers of SM donors reported in recent years, DTP-[2F]BT SM analogues are in general not prone to dramatic performance variations in BHJ thin films cast with processing additives. Our results indicate that the role of SVA steps is not independent of the molecular structure of the SM donors used in the BHJ solar cells.

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“…Regarding this problem, many efforts were taken to optimize the charge transport efficiency in the HBSCs, such as annealing of the as-prepared hybrid films [5], modification on structure of molecule chains [6–9], and solvent treatment [10, 11]. Most of the process aimed at enhancing orientation of molecule chains or crystallization of polymer matrix so that to increase the charge motility.…”

Section: Introductionmentioning

confidence: 99%

Efficient Organic/Inorganic Hybrid Solar Cell Integrating Polymer Nanowires and Inorganic Nanotetrapods

Tan

Liu

et al. 2017

Nanoscale Res Lett

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Constructing a highly efficient bulk-heterojunction is of critical importance to the hybrid organic/inorganic solar cells. Here in this work, we introduce a novel hybrid architecture containing P3HT nanowire and CdSe nanotetrapod as bicontinuous charge channels for holes and electrons, respectively. Compared to the traditionally applied P3HT molecules, the well crystallized P3HT nanowires qualify an enhanced light absorption at the long wavelength as well as strengthened charge carrier transport in the hybrid active layer. Accordingly, based on efficient dissociation of photogenerated excitons, the interpercolation of these two nano-building blocks allows a photovoltaic conversion efficiency of 1.7% in the hybrid solar cell, up to 42% enhancement compared to the reference solar cell with traditional P3HT molecules as electron donor. Our work provides a promising hybrid structure for efficient organic/inorganic bulk-heterojunction solar cells.

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Solution-Processed Diketopyrrolopyrrole-Containing Small-Molecule Organic Solar Cells with 7.0% Efficiency: In-Depth Investigation on the Effects of Structure Modification and Solvent Vapor Annealing

Cited by 108 publications

References 98 publications

Film morphology evolution during solvent vapor annealing of highly efficient small molecule donor/acceptor blends

Film morphology evolution during solvent vapor annealing of highly efficient small molecule donor/acceptor blends

Solvent Annealing Effects in Dithieno[3,2-b:2′,3′-d]pyrrole–5,6-Difluorobenzo[c][1,2,5]thiadiazole Small Molecule Donors for Bulk-Heterojunction Solar Cells

Efficient Organic/Inorganic Hybrid Solar Cell Integrating Polymer Nanowires and Inorganic Nanotetrapods

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