Straightforward access to diketopyrrolopyrrole (DPP) dimers

Stas, Sara; Balandier, Jean‐Yves; Lemaur, Vincent; Fenwick, Oliver; Tregnago, Giulia; Quist, Florence; Cacialli, Franco; Cornil, Jérôme; Geerts, Yves

doi:10.1016/j.dyepig.2012.12.005

Cited by 38 publications

(17 citation statements)

References 51 publications

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“…[12,14,16] However, this explanation contradicts the general understanding for the effect of π−conjugation length on spectroscopic behaviours. Moreover, a recent study by Fritzner et al on the influence of thiophenes between 1-(1,1-dicyanomethylene)-cyclohex-2-ene (DCC) units has clearly showed that the expected bathrochromic shift in absorption is actually observed for their materials with longer thiophene bridges.…”

Section: Introductionmentioning

confidence: 50%

“…As a compromise, π-conjugated dimers of such as DPP chromophores have recently gained significant interest due to their aforementioned high reproducibility in material synthesis and good device performance, approaching to those of polymeric chromophores due to their extended π-conjugation. [7][8][9][10][11][12][13][14][15] Interestingly, thiophene bridged DPP dimers show an unusual spectroscopic behaviour: an extension of the thiophene bridge results in an unusual hypsochromical shift in the solution absorption spectrum. This intuitively phenomenon has often been ascribed to an enhanced freedom of rotation with the increased number of thiophene units, leading to an…”

Section: Introductionmentioning

confidence: 99%

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Aggregates of diketopyrrolopyrrole dimers in solution

et al. 2017

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Abstract3D excitation-emission spectroscopy disentangles the spectroscopic properties of aggregates and non-aggregates of DPPs based dimers, Rertob Wawrzinek, Xiuwen Zhou, Mujeeb Ullah, Ebinazar B. Namdasa, and Shih-Chun Lo M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT AbstractDimers based on diketopyrrolopyrrole (DPP) chromophores have gained tremendous interest as an excellent material building block for organic solar cells and photodiodes.However, a counterintuitively blue shift in their solution absorption spectra of DPP chromophores occurs with an increasing number of thiophene bridging units. We allocate this as chromophore aggregates in solution, which might hinder adequate mixing in the blends, leading to poor film forming quality and reduced charge generation in solution processed devices. Hence, identification of such aggregates is crucial in order to find measures for device optimisation. In this study, we present synthesis and characterisation of three pyridyl end-capped DPP dimers of different conjugation length using thiophene linkers and compare their parent monomer to evidence the behaviours of aggregates in solution.We employ conventional and temperature dependent UV-Vis spectroscopy, fluorescence and excitation-emission spectroscopy as well as TD-DFT calculations to show that such DPP dimers predominantly form aggregates in solution even at low concentrations. By disentangling the spectroscopic behaviour of both aggregated and non-aggregated species, we refute literature's explanation that the apparent blue shift in absorption arises from a reduced conjugation length due to more molecular flexibility. Instead, absorption and emission signals of non-aggregated dimers are mostly masked by their aggregated species.This work provides a tool set using common laboratory spectroscopic equipment to identify and characterise solution aggregates-information particularly important towards optimisation of organic electronics processed from solution.

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Section: Introductionmentioning

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Aggregates of diketopyrrolopyrrole dimers in solution

et al. 2017

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“…1d). DPP derivatives are versatile dyes exhibiting a favourable combination of optoelectronic properties [37][38][39] that have been extensively investigated and exploited in a very broad range of applications, including organic transistors 40 , solar cells 41 and OLEDs 42 . Interestingly, the optical properties of DPP can be drastically modified by leveraging its highly electron-poor nature and the socalled "push-pull" approach to obtain red-to-NIRemitting derivatives that combine both enhanced nonlinear optical properties and high photoluminescence (PL) quantum efficiencies 43 .…”

Section: Resultsmentioning

confidence: 99%

Visible light communication with efficient far-red/near-infrared polymer light-emitting diodes

et al. 2020

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Visible light communication (VLC) is a wireless technology that relies on optical intensity modulation and is potentially a game changer for internet-of-things (IoT) connectivity. However, VLC is hindered by the low penetration depth of visible light in non-transparent media. One solution is to extend operation into the "nearly (in)visible" near-infrared (NIR, 700-1000 nm) region, thus also enabling VLC in photonic bio-applications, considering the biological tissue NIR semitransparency, while conveniently retaining vestigial red emission to help check the link operativity by simple eye inspection. Here, we report new far-red/NIR organic light-emitting diodes (OLEDs) with a 650-800 nm emission range and external quantum efficiencies among the highest reported in this spectral range (>2.7%, with maximum radiance and luminance of 3.5 mW/cm 2 and 260 cd/m 2 , respectively). With these OLEDs, we then demonstrate a "real-time" VLC setup achieving a data rate of 2.2 Mb/s, which satisfies the requirements for IoT and biosensing applications. These are the highest rates ever reported for an online unequalised VLC link based on solution-processed OLEDs.

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“…These are chemically and thermally stable materials with optical properties tunable by para and meta position substituents. 32 They have found important industrial applications as dyes, such as pigment red 254 -known colloquially as "Ferrari red" for its extensive use in automotive paints -but their derivatives have also been investigated as photoluminescent materials 33,34 (including for cellular imaging 35 ), dyes in solar cells, 36 sensors, 37 high-mobility ambipolar semiconductors, 36,38 and light-emitting diodes. [39][40][41][42][43][44][45][46] Their use as solid-state emitters has, however, been limited by quenching of the emission by a strong propensity towards aggregation of molecules caused by π -π interactions and hydrogen bonding.…”

confidence: 99%

Efficient red electroluminescence from diketopyrrolopyrrole copolymerised with a polyfluorene

et al. 2013

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We report the synthesis, characterization, and device incorporation of copolymers based on a common green-emitting polyfluorene but containing a small proportion of a low energy gap donor-acceptor-donor unit for red emission in photo- and electro-luminescence. At just 1%–3% random incorporation, the low-gap unit is not present on all chains, yet we demonstrate that efficient charge and energy transfer can yield electroluminescent devices with 1% quantum efficiency and a color that can be tuned by adjusting the density of low-gap units to achieve primary red (National Television System Committee). The high current density tail off in the efficiency is reduced by replacing the hole-injection layer with a photochemically cross-linked electron‑blocking layer.

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Straightforward access to diketopyrrolopyrrole (DPP) dimers

Cited by 38 publications

References 51 publications

Aggregates of diketopyrrolopyrrole dimers in solution

Aggregates of diketopyrrolopyrrole dimers in solution

Visible light communication with efficient far-red/near-infrared polymer light-emitting diodes

Efficient red electroluminescence from diketopyrrolopyrrole copolymerised with a polyfluorene

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