Effects of aromatic substituents on the electronic structure and excited state energy levels of diketopyrrolopyrrole derivatives for singlet fission

2018 ◽  
Vol 20 (35) ◽  
pp. 22997-23006 ◽  
Author(s):  
Li Shen ◽  
Zhaofeng Tang ◽  
Xuemin Wang ◽  
Heyuan Liu ◽  
Yanli Chen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
State Energy ◽  
Energy Levels ◽  
Singlet Fission ◽  
Excited State Energy

Aryl-substituted diketopyrrolopyrrole-based singlet fission candidates have been designed and evaluated for extending the library of singlet fission sensitizers.

scholarly journals Excited State Character of Cibalackrot-Type Compounds Interpreted in Terms of Hückel-Aromaticity: A Rational for Singlet Fission Chromophore Design

2021 ◽  
Author(s):  
Weixuan Zeng ◽  
Ouissam El Bakouri ◽  
Dariusz Szczepanik ◽  
Hugo Bronstein ◽  
Henrik Ottosson
Keyword(s):  
Excited State ◽  
Theoretical Analysis ◽  
Excited States ◽  
State Energy ◽  
Energy Levels ◽  
Singlet Fission ◽  
Excited State Energy ◽  
Organic Chromophores ◽  
Spin Populations ◽  
Triplet Excited States

The exact energies of the lowest singlet and triplet excited states in organic chromophores are crucial to their performance in optoelectronic devices. The possibility of utilizing singlet fission to enhance the performance of photovoltaic devices has resulted in a wide demand for tuneable, stable organic chromophores with wide S<sub>1</sub> – T<sub>1</sub> energy gaps (>1 eV). Cibalackrot-type compounds were recently considered to have favorably positioned excited state energies for singlet fission, and they were found to have a degree of aromaticity in the lowest triplet excited state (T<sub>1</sub>). This work reports on a revised and deepened theoretical analysis taking into account the excited state Hückel-aromatic (instead of Baird-aromatic) as well as diradical characters, with the aim to design new organic chromophores based on this scaffold in a rational way starting from qualitative theory. We demonstrate that the substituent strategy can effectively adjust the spin populations on the chromophore moieties and thereby manipulate the excited state energy levels. Additionally, the improved understanding of the aromatic characters enables us to demonstrate a feasible design strategy to vary the excited state energy levels by tuning the number and nature of Hückel-aromatic units in the excited state. Finally, our study elucidates the complications and pitfalls of the excited state aromaticity and antiaromaticity concepts, highlighting that quantitative results from quantum chemical calculations of various aromaticity indices must be linked with qualitative theoretical analysis of the character of the excited states.

Controlling the excited-state energy levels of 9,9′-bifluorenylidene derivatives by twisting their structure to attaining singlet fission character in organic photovoltaics

2017 ◽  
Vol 5 (20) ◽  
pp. 4909-4914 ◽  
Author(s):  
So Kawata ◽  
Junki Furudate ◽  
Takuya Kimura ◽  
Hiroko Minaki ◽  
Ayaka Saito ◽  
...  
Keyword(s):  
Excited State ◽  
Double Bond ◽  
Organic Photovoltaics ◽  
State Energy ◽  
Energy Levels ◽  
Singlet Fission ◽  
Excited State Energy

9,9′-Bifluorenylidene (BFN) derivatives, in which the two fluorene moieties are connected via a CC double bond at the 9-position, are expected to show singlet fission (SF) character in organic photovoltaics (OPVs).

scholarly journals Excited State Character of Cibalackrot-Type Compounds Interpreted in Terms of Hückel-Aromaticity: A Rational for Singlet Fission Chromophore Design

2021 ◽  
Author(s):  
Weixuan Zeng ◽  
Ouissam El Bakouri ◽  
Dariusz Szczepanik ◽  
Hugo Bronstein ◽  
Henrik Ottosson
Keyword(s):  
Excited State ◽  
Theoretical Analysis ◽  
Excited States ◽  
State Energy ◽  
Energy Levels ◽  
Singlet Fission ◽  
Excited State Energy ◽  
Organic Chromophores ◽  
Spin Populations ◽  
Triplet Excited States

The exact energies of the lowest singlet and triplet excited states in organic chromophores are crucial to their performance in optoelectronic devices. The possibility of utilizing singlet fission to enhance the performance of photovoltaic devices has resulted in a wide demand for tuneable, stable organic chromophores with wide S<sub>1</sub> – T<sub>1</sub> energy gaps (>1 eV). Cibalackrot-type compounds were recently considered to have favorably positioned excited state energies for singlet fission, and they were found to have a degree of aromaticity in the lowest triplet excited state (T<sub>1</sub>). This work reports on a revised and deepened theoretical analysis taking into account the excited state Hückel-aromatic (instead of Baird-aromatic) as well as diradical characters, with the aim to design new organic chromophores based on this scaffold in a rational way starting from qualitative theory. We demonstrate that the substituent strategy can effectively adjust the spin populations on the chromophore moieties and thereby manipulate the excited state energy levels. Additionally, the improved understanding of the aromatic characters enables us to demonstrate a feasible design strategy to vary the excited state energy levels by tuning the number and nature of Hückel-aromatic units in the excited state. Finally, our study elucidates the complications and pitfalls of the excited state aromaticity and antiaromaticity concepts, highlighting that quantitative results from quantum chemical calculations of various aromaticity indices must be linked with qualitative theoretical analysis of the character of the excited states.

Evaluation of AlGaAs/GaAs Heterointerface by Shubnikov-de Haas Oscillation Measurements

1986 ◽  
Vol 77 ◽  
Author(s):  
Kazumi Kasai ◽  
H. Tanaka ◽  
H. Itoh ◽  
T. Oh-Hori ◽  
M. Takikawa ◽  
...  
Keyword(s):  
Excited State ◽  
State Energy ◽  
Energy Levels ◽  
Interface Model ◽  
Dimensional Electron ◽  
Excited State Energy ◽  
Haas Oscillation ◽  
First Excited State ◽  
A New Technique

ABSTRACTThe measurement of Shubnikov-de Haas(SdH) oscillation is proposed as a new technique for evaluating the quality of a heterointerface. The first excited state of 2-dimensional electron energy levels is determined for several samples using the measurements of SdH oscillation. Lower values of the first excited state energy are found for the samples with a low mobility. The low value can be approximately explained in terms of graded interface model.

Influence of molecular configuration and functional substituents on excited state energy levels in two naphthyl-based phosphine oxide hosts

2012 ◽  
Vol 13 (9) ◽  
pp. 1516-1525 ◽  
Author(s):  
Hui Xu ◽  
Guohua Xie ◽  
Chunmiao Han ◽  
Zhensong Zhang ◽  
Zhaopeng Deng ◽  
...  
Keyword(s):  
Excited State ◽  
Phosphine Oxide ◽  
State Energy ◽  
Energy Levels ◽  
Molecular Configuration ◽  
Excited State Energy

scholarly journals Damming a Molecular Energy Reservoir: Ion-regulated Electronic Energy Shuttling in a [2]Rotaxane

2021 ◽  
Author(s):  
Shilin Yu ◽  
Arkady Kurpryakov ◽  
James Lewis ◽  
Vicente Martí-Centelles ◽  
Stephen Goldup ◽  
...  
Keyword(s):  
Excited State ◽  
Kinetic Parameters ◽  
State Energy ◽  
Energy Levels ◽  
Electronic Energy ◽  
Cation Binding ◽  
Potential Mechanism ◽  
Delayed Luminescence ◽  
Excited State Energy

Bidirectional electronic energy shuttling is shown to occur between the molecular ring and axle components of a rotaxane. The engineered energetic and kinetic parameters give rise to long-lived, delayed luminescence. Perturbation of the quasi-isoenergetic ring and stopper chromophore excited-state energy levels upon cation binding influences the energy shuttling process, and hence luminescence read-out, representing a new potential mechanism in luminescent molecular chemosensor development

scholarly journals Damming a Molecular Energy Reservoir: Ion-regulated Electronic Energy Shuttling in a [2]Rotaxane

2021 ◽  
Author(s):  
Shilin Yu ◽  
Arkady Kurpryakov ◽  
James Lewis ◽  
Vicente Martí-Centelles ◽  
Stephen Goldup ◽  
...  
Keyword(s):  
Excited State ◽  
Kinetic Parameters ◽  
State Energy ◽  
Energy Levels ◽  
Electronic Energy ◽  
Cation Binding ◽  
Potential Mechanism ◽  
Delayed Luminescence ◽  
Excited State Energy

Bidirectional electronic energy shuttling is shown to occur between the molecular ring and axle components of a rotaxane. The engineered energetic and kinetic parameters give rise to long-lived, delayed luminescence. Perturbation of the quasi-isoenergetic ring and stopper chromophore excited-state energy levels upon cation binding influences the energy shuttling process, and hence luminescence read-out, representing a new potential mechanism in luminescent molecular chemosensor development

How size, edge shape, functional groups and embeddedness influence the electronic structure and partial optical properties of graphene nanoribbons

2021 ◽  
Vol 23 (36) ◽  
pp. 20695-20701
Author(s):  
Jin Feng ◽  
Xinlong Mao ◽  
Hongxia Zhu ◽  
Zhe yang ◽  
Mengdi Cui ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Excited State ◽  
Band Structure ◽  
Functional Groups ◽  
Electron Distribution ◽  
State Energy ◽  
Functional Group ◽  
Graphene Nanoribbons ◽  
Excited State Energy

The size, edge shape, functional group and embeddedness affect the properties, including the band structure, excited state energy and electron distribution, of GNRs.

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