Color Fine‐Tuning of Optical Materials Through Rational Design

Holzer, Brigitte; Bintinger, Johannes; Lumpi, Daniel; Choi, Christopher; Kim, Young-Wan; Stöger, Berthold; Hametner, Christian; Marchetti‐Deschmann, Martina; Plasser, Felix; Horkel, Ernst; Kymissis, Ioannis; Fröhlich, Johannes

doi:10.1002/cphc.201601204

Cited by 19 publications

(18 citation statements)

References 64 publications

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“…To the best of our knowledge such a strategy has never been used for excited state analysis. [5,[59][60][61][62][63] Computations were performed on the oligomer containing six thiophene units (OT6) using TDDFT in the Tamm-Dancoff approximation [64][65][66] with the CAM-B3LYP functional [67][68][69] and Ahlrichs' SV(P) basis set. Practically, W AB and 1 h:A e are evaluated in the spirit of a Löwdin population analysis, [56][57][58] see Section S1 of the Supporting Information (SI) for details.…”

Section: Felix Plasser* [A]mentioning

confidence: 99%

Visualisation of Electronic Excited‐State Correlation in Real Space

Plasser

2019

ChemPhotoChem

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A method for the visualisation of excited-state electron correlation is introduced and shown to address two notorious problems in excited-state electronic structure theory, the analysis of excitonic correlation and the distinction between covalent and ionic wavefunction character. The method operates by representing the excited state in terms of electron and hole quasiparticles, fixing the hole on a fragment of the system and observing the resulting conditional electron density in real space. The application of this approach to oligothiophene, an exemplary conjugated polymer, illuminates excitonic correlation effects of its excited states in unprecedented clarity and detail. A study of naphthalene shows that the distinction between the ionic and covalent states of this molecule, which has so far only been achieved using elaborate valence-bond theory protocols, arises naturally in terms of electron-hole avoidance and enhanced overlap, respectively. More generally, the method is relevant for any excited state that cannot be described by a single electronic configuration.Electronically excited states of molecules form the underpinnings of a wide range of processes of utmost scientific interest, such as light-driven natural processes [1,2] photochemical reactions, [3] signalling and sensing, [4] and the operation of organoelectronic materials. [5,6] Computational photochemistry has become an indispensable part of scientific investigations in these areas through two main tasks, the interpretation of experimental results and the prediction of unknown photophysical properties. Indeed, the predictive power of computational photochemistry has steadily increased over the recent years due to the tremendous effort spent in the development of new methods as well as rapid progress in computer technology. [7][8][9][10][11][12] However, the interpretation of this wealth of computational data can act as a significant impediment in practical work. Therefore, a number of analysis tools have been developed to quantify excited-state properties [13][14][15][16][17] and to visualise the molecular orbitals (MOs) involved and their location in space in a compact and rigorous way. [18][19][20][21][22][23] However, the above-mentioned visualisation tools -and the MO picture itself -break down if the information of interest does not lie in the MOs themselves but in the interaction of different quasidegenerate electronic configurations. Such cases are widespread and two notorious failures of the MO picture relate to excitons in extended systems [24][25][26] and to ionic/ covalent wavefunction character in alternant hydrocarbons. [27,28] The first case is related to the emergence of band structure in large systems, which leads to excited states formed as a superposition of many different electronic configurations whose description requires moving from the MO picture to a representation in terms of correlated electron and hole quasiparticles. [26,[29][30][31] Previous attempts of visualising the ensuing correlated electron-hole distribution ha...

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Section: Felix Plasser* [A]mentioning

confidence: 99%

Visualisation of Electronic Excited‐State Correlation in Real Space

Plasser

2019

ChemPhotoChem

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“…Some works also show that the tetraaryl-1,4-dihydropyrrolo- [3,2-b]pyrrole derivatives can be used as starting materials to synthesize other electron-rich structures, including pentaaryl-and hexaaryl-1,4-dihydropyrrolo- [ [3,2-b]pyrrole derivatives has been demonstrated in applications such as the halocarbon detection cartridges [28] and the organic resistive memory [29]. However, in the field of photoelectronics, the pyrrolo [3,2-b]pyrrole derivatives are not yet studied, but similar heteropentalenes such as thieno [3,2-b]thiophenes appear as dyes in dye-sensitized solar cells (DSSC) [30,31], as hole transporters in Perovskite solar cells (PSC) [32], in organic light emitting diodes (OLED) [33], organic light emitting transistors (OLET) [34], organic phototransistors (OPT) [35] and organic photovoltaic cells (OPV) [36]. Pyrrolo [3,2-b]pyrrole derivatives can be synthesized via Knoevenagel reaction between pyrrolo-2-carboxialdehydes and ethyl azidoacetate, with a subsequent thermal cyclization [37].…”

Section: Introductionmentioning

confidence: 99%

Improved synthesis of tetraaryl-1,4-dihydropyrrolo[3,2-b]pyrroles a promising dye for organic electronic devices: An experimental and theoretical approach

et al. 2018

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Pyrrolo-[3,2-b]pyrroles represent a class of promising materials for application in organic electronics with interesting optoelectronic properties and great synthesis versatility, but yields obtained from varied synthetic routes are still very low, hindering their effective application for industrial purposes. In this report, we present a method for the synthesis of tetraaryl-1,4-dihydropyrrolo-[3,2-b]pyrrole derivatives by multicomponent reactions employing niobium pentachloride as a catalyst. The optical characterization of the products is also presented. Electronic structure calculations were performed to help the interpretation of the synthesis process, as well as the optical properties of the systems. Excellent yields and low reaction times were obtained, indicating that NbCl 5 is an efficient catalyst for such systems. The products show promising properties for optoelectronic applications that can be adjusted by the choice of benzaldehyde derivatives used in the synthesis.

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“…2,27,28 Recently, we published on TPA-substituted oligothiophenes constituting a new substance class suitable for tailoring emission properties (Scheme 1A, BRA-1T, R denoting different substituents). [29][30][31] First photophysical results also revealed the strong two-photon absorption of these compounds 32 suitable for 2PP (Scheme 1B). In this article, we investigate the photophysical properties including the excited state dynamics of these novel 2PA PIs and correlate these findings to the electronic nature of the substituent R on the TPA moiety (varying from electron-donating (-OMe, -tBu, -Me, -TMS), electronneutral (-H) to electron-withdrawing (-F, -CN, -SO 2 Me)).…”

Section: Introductionmentioning

confidence: 92%