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 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 Excimers in Multichromophoric Assemblies: Boon or Bane?

2021 ◽  
Author(s):  
Debansu Chaudhuri
Keyword(s):  
Excited State ◽  
Fluorescence Quenching ◽  
Organic Semiconductors ◽  
Light Emission ◽  
Singlet Fission ◽  
Circularly Polarized ◽  
Exciton Migration ◽  
Organic Systems ◽  
Polarized Emission ◽  
Recent Developments

Exciton dynamics in organic semiconductors is a subject of great significance from the standpoint of light emission, as well as light harvesting. As transient excited state species, excimers are expected to play a significant role in the dynamics and the fate of the excited state. Till recently, the discourse on excimers in organic systems revolved around their role in aggregation induced fluorescence quenching, or utilizing their characteristic red-shifted emission to report local interactions. But in the last decade, research in the area of organic multichromophoric systems has brought the spotlight back on this fascinating species. This review focuses on recent developments that highlight the importance of excimers in various processes involving multichromophoric systems, such as circularly polarized emission, exciton migration and singlet fission (SF). The review also attempts to address the question of whether excimers are useful or detrimental to various photophysical and photochemical processes of importance.

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 Intermolecular vibrations mediate ultrafast singlet fission

2020 ◽  
Vol 6 (38) ◽  
pp. eabb0052 ◽  
Author(s):  
Hong-Guang Duan ◽  
Ajay Jha ◽  
Xin Li ◽  
Vandana Tiwari ◽  
Hanyang Ye ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Potential Energy Surfaces ◽  
Excited Electronic State ◽  
Electronic Spectroscopy ◽  
Low Frequency ◽  
Conical Intersection ◽  
Singlet Fission ◽  
Singlet Exciton ◽  
Spin Singlet ◽  
Triplet Pair

Singlet fission is a spin-allowed exciton multiplication process in organic semiconductors that converts one spin-singlet exciton to two triplet excitons. It offers the potential to enhance solar energy conversion by circumventing the Shockley-Queisser limit on efficiency. We study the primary steps of singlet fission in a pentacene film by using a combination of TG and 2D electronic spectroscopy complemented by quantum chemical and nonadiabatic dynamics calculations. We show that the coherent vibrational dynamics induces the ultrafast transition from the singlet excited electronic state to the triplet-pair state via a degeneracy of potential energy surfaces, i.e., a multidimensional conical intersection. Significant vibronic coupling of the electronic wave packet to a few key intermolecular rocking modes in the low-frequency region connect the excited singlet and triplet-pair states. Along with high-frequency local vibrations acting as tuning modes, they open a new channel for the ultrafast exciton transfer through the resulting conical intersection.

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