Diketopyrrolopyrrole (DPP)-based materials for organic photovoltaics

Qu, Sanyin; Tian, He

doi:10.1039/c2cc17886a

Cited by 602 publications

(368 citation statements)

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“…To the best of our knowledge there are no published values of λ h/e hitherto for any DPPs despite the ever-growing number of publications involving their use in CT based materials. [9][10][11][12][13][14][15][16][17][18][19][20] The rest of the paper is laid out as follows; first, we give a brief description of the computation methods used to determine λ h/e (according to Equations 2-4). In the results and discussion section we first describe the influence of basis set and DFT employed on the computed λ h/e values of H 2 P 2 DPP.…”

Section: Introductionmentioning

confidence: 99%

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Torsional angle dependence and switching of inner sphere reorganisation energies for electron and hole transfer processes involving phenyl substituted diketopyrrolopyrroles; a density functional study

2015

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angle dependence and switching of inner sphere reorganisation energies for electron and hole transfer processes involving phenyl substituted diketopyrrolopyrroles; a density functional study ', Dyes and Pigments, Vol. 113, pp. 609-617, February 2015 AbstractDetermination of inner sphere reorganisation energies is important in the development of organic charge mediating materials and electron transfer reactions. In this study, hole and electron inner sphere reorganisation energies, λ h and λ e respectively, have been computed for the first time for a series of structurally related diketopyrrolopyrrole (DPP) molecular motifs. Inner sphere reorganisation energies for self-exchange electron transfer reactions are calculated as being lower than those associated hole transfer processes in model planar phenyl and thiophenyl substituted DPP systems. It is found that λ e < λ h for all planar ring / DPP core structures examined. The effect on λ h/e of nonplanarity between phenyl substituents and DPP core is explored in detail. The relative ordering of λ h and λ e is dependent upon the torsional angle of phenyl rings and reverses at twist angles of greater than 60⁰ such that λ e > λ h .

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Section: Introductionmentioning

confidence: 99%

“…[14][15][16][17][18][19][20][21] We have recently undertaken a detailed characterisation of the photophysical, photochemical and charge transfer, CT properties of single molecule DPPs in solution, the solid phase and in thin films with a view to ultimately developing novel sensor applications and electronic devices.…”

Section: Introductionmentioning

confidence: 99%

Torsional angle dependence and switching of inner sphere reorganisation energies for electron and hole transfer processes involving phenyl substituted diketopyrrolopyrroles; a density functional study

2015

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“…However, the major focus of the research has been to focus on using the DPP unit within the donor polymer material 65 . In particular by using various coupling reactions (generally palladium catalysed) a broad …”

Section: Dpp Based Polymer Materials For Opvsmentioning

confidence: 99%

Low optical gap materials for organic solar cells - research and application

Chandrasekharan¹

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In spite of the cost of silicon solar cells decreasing in recent years, there is considerable interest in solar cells with lightweight and flexible forms. Organic semiconductor-based photovoltaic cells (OPVs) have the potential to offer low cost, lightweight and flexible devices. At this stage there is still much to be improved for OPVs as the efficiencies are still lower than their inorganic counterparts. Polymeric materials have been more widely studied than their non-polymeric counterparts. In recent years OPVs polymeric donor materials have emerged with efficiencies reaching 10% with quite a range of materials now providing efficiencies of around 7%. However, the problem with semiconducting polymers is that control of the regioregularity, poly(dispersity), and molecular weight from batch-to-batch is not a simple process. Solution-processable nonpolymeric semiconductors are attractive for opto-electronic applications as they are simpler to synthesise, purify, characterise, and the optical properties can be more easily fine-tuned. In this context, diketopyrrolopyrrole (DPP) based small molecules have shown promising results with devices efficiencies reaching around 5-6%. Key properties of the DPP unit are strong π-π interactions, and suitable and tunable energy levels. These properties have been the main drivers in their use in OPVs.This thesis consist of the synthesis, characterisation, and bulk hetrojunction (BHJ) devices properties of novel DPP(ThAr) 2 non-polymeric materials. Accordingly, a first series of compounds was synthesized with different electron affinity groups such as fluorenone (Fl) [EhDPP(ThFl) 2 and OddDPP(ThFl) 2 ] and benzothiadiazole (Bt) [OddDPP(ThBt) 2 ] attached to the distal ends of a bisthienyl-diketopyrrolopyrrole unit DPP(Th) 2 unit. The 'DPP(ThAr) 2 ' derivatives were synthesised under standard Suzuki-Miyaura cross-coupling or by direct arylation reaction conditions and the rate of the direct arylation reaction was found to be faster than for the Suzuki-Miyaura crosscoupling reactions. The solubility of the compounds was poor when the 2-ethylhexyl (Eh) moiety was used as the solubilising group for DPP(ThFl) 2 . 2-Octyldodecyl (Odd) solubilising groups gave better solubility in chlorinated solvents, which are typically used in OPV fabrication. The three nonpolymeric DPP materials exhibited bipolar charge transport in organic field effect transistors (OFETs), with hole and electron mobility in the order of 10 -2 −10 -3 cm 2 V -1 s -1 , and in a diode architecture OddDPP(ThFl) 2 and OddDPP(ThBt) 2 exhibited mobilities of the order of 10 -4 cm 2 V -1 s -1 for pristine films. In BHJ devices using [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM)as the acceptor, different solvent mixtures were used for device fabrication to achieve the maximum efficiency. The EQE spectra of the blend film suggested that charge generation due to absorption at iii wavelengths longer than 750 nm occurred through the Channel I pathway, and at wavelengths shorter than 750 nm, both Channel I and II ...

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“…[24][25][26][27] In many publications, the DPP derivatives have been highlighted as a good emitter for OLED devices but nevertheless small molecule OLEDs based on such compounds have not been investigated, despite their very high intensity and PLQY in solution. Unfortunately, DPP derivatives demonstrate strong π-stacked aggregation that may lead to dissipative intermolecular charge transfer and aggravate charge recombination that quenches fluorescence.…”

Section: Introductionmentioning

confidence: 99%

Exciplex Enhancement as a Tool to Increase OLED Device Efficiency

et al. 2016

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(2016) 'Exciplex enhancement as a tool to increase OLED device e ciency.', Journal of physical chemistry C., 120 (4). pp. 2070-2078. Further information on publisher's website:https://doi.org/10.1021/acs.jpcc.5b11263 Publisher's copyright statement: This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Journal of physical chemistry C, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see https://doi.org/10.1021/acs.jpcc.5b11263Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. derivatives that could be used as emitters in OLED devices. We were able to improve the of efficiency DPP materials by forming exciplex enhanced OLED devices. These organic materials were also characterized by electrochemical and spectroscopic methods in order to elucidate each molecule's interaction and decreasing the photoluminescence efficiency.2

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Diketopyrrolopyrrole (DPP)-based materials for organic photovoltaics

Cited by 602 publications

References 104 publications

Torsional angle dependence and switching of inner sphere reorganisation energies for electron and hole transfer processes involving phenyl substituted diketopyrrolopyrroles; a density functional study

Torsional angle dependence and switching of inner sphere reorganisation energies for electron and hole transfer processes involving phenyl substituted diketopyrrolopyrroles; a density functional study

Low optical gap materials for organic solar cells - research and application

Exciplex Enhancement as a Tool to Increase OLED Device Efficiency

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