Computationally Driven Design Principles for Singlet Fission in Organic Chromophores

2019 ◽  
Vol 123 (32) ◽  
pp. 19257-19268 ◽  
Author(s):  
Kalishankar Bhattacharyya ◽  
Ayan Datta
Keyword(s):  
Design Principles ◽  
Singlet Fission ◽  
Organic Chromophores

scholarly journals Emerging Design Principles for Enhanced Solar Energy Utilization with Singlet Fission

2019 ◽  
Vol 123 (7) ◽  
pp. 3923-3934 ◽  
Author(s):  
Melissa K. Gish ◽  
Natalie A. Pace ◽  
Garry Rumbles ◽  
Justin C. Johnson
Keyword(s):  
Solar Energy ◽  
Design Principles ◽  
Energy Utilization ◽  
Singlet Fission ◽  
Solar Energy Utilization

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.

scholarly journals Controlling Singlet Fission with Coordination Chemistry-Induced Assembly of Dipyridyl Pyrrole Bipentacenes

2020 ◽  
Author(s):  
Ryan Ribson ◽  
Gyeongshin Choi ◽  
Ryan Hadt ◽  
Theodor Agapie
Keyword(s):  
Coordination Chemistry ◽  
Structural Changes ◽  
Information Science ◽  
Rate Increase ◽  
Design Principles ◽  
Singlet Fission ◽  
Photophysical Parameters ◽  
Novel Design ◽  
Triplet Lifetime

Singlet fission has the potential to surpass current efficiency limits in next-generation photovoltaics and to find use in quantum information science. Despite the demonstration of singlet fission in various materials, there is still a great need for fundamental design principles that allow for tuning of photophysical parameters, including the rate of fission and triplet lifetimes. Here we describe the synthesis and photophysical characterization of a novel bipentacene dipyridyl pyrrole (HDPP-Pent) and its Li- and K-coordinated derivatives. HDPP-Pent undergoes singlet fission at roughly 50% efficiency (τ<sub>SF</sub> = 730 ps), whereas coordination in the Li complex induces significant structural changes to generate a dimer, resulting in a 5-fold rate increase (τ<sub>SF</sub> = 140 ps) and near fully efficient singlet fission with virtually no sacrifice in triplet lifetime. We thus illustrate novel design principles to produce favorable singlet fission properties, wherein through-space control can be achieved via coordination chemistry-induced multi-pentacene assembly.

scholarly journals Design principles for efficient singlet fission in anthracene-based organic semiconductors

2019 ◽  
Author(s):  
YounJue Bae ◽  
Joseph Christensen ◽  
Gyeongwon Kang ◽  
Christos D. Malliakas ◽  
Jiawang Zhou ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Design Principles ◽  
Singlet Fission

scholarly journals Controlling Singlet Fission with Coordination Chemistry-Induced Assembly of Dipyridyl Pyrrole Bipentacenes

2020 ◽  
Author(s):  
Ryan Ribson ◽  
Gyeongshin Choi ◽  
Ryan Hadt ◽  
Theodor Agapie
Keyword(s):  
Coordination Chemistry ◽  
Structural Changes ◽  
Information Science ◽  
Rate Increase ◽  
Design Principles ◽  
Singlet Fission ◽  
Photophysical Parameters ◽  
Novel Design ◽  
Triplet Lifetime

Singlet fission has the potential to surpass current efficiency limits in next-generation photovoltaics and to find use in quantum information science. Despite the demonstration of singlet fission in various materials, there is still a great need for fundamental design principles that allow for tuning of photophysical parameters, including the rate of fission and triplet lifetimes. Here we describe the synthesis and photophysical characterization of a novel bipentacene dipyridyl pyrrole (HDPP-Pent) and its Li- and K-coordinated derivatives. HDPP-Pent undergoes singlet fission at roughly 50% efficiency (τ<sub>SF</sub> = 730 ps), whereas coordination in the Li complex induces significant structural changes to generate a dimer, resulting in a 5-fold rate increase (τ<sub>SF</sub> = 140 ps) and near fully efficient singlet fission with virtually no sacrifice in triplet lifetime. We thus illustrate novel design principles to produce favorable singlet fission properties, wherein through-space control can be achieved via coordination chemistry-induced multi-pentacene assembly.

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.

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