Coherent carrier and exciton transport in organic semiconductors

2020 ◽  
Author(s):  
Robert Binder ◽  
Wjatscheslaw Popp ◽  
Dominik Brey ◽  
Irene Burghardt
Keyword(s):  
Organic Semiconductors ◽  
Exciton Transport

scholarly journals Exciton transport in molecular organic semiconductors boosted by transient quantum delocalization

2022 ◽  
Author(s):  
Samuele Giannini ◽  
Wei-Tao Peng ◽  
Lorenzo Cupellini ◽  
Daniele Padula ◽  
Antoine Carof ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Diffusion Constant ◽  
Reorganization Energy ◽  
Clear Correlation ◽  
Optoelectronic Materials ◽  
Surface Hopping ◽  
Exciton Transport ◽  
Organic Optoelectronic Devices ◽  
Organic Optoelectronic ◽  
Quantum Delocalization

Abstract Designing molecular materials with very large exciton diffusion lengths would remove some of the intrinsic limitations of present-day organic optoelectronic devices. Yet, the nature of excitons in these materials is still not sufficiently well understood. Here we present Frenkel exciton surface hopping, a highly efficient method to propagate excitons through truly nano-scale materials by solving the time-dependent Schrödinger equation coupled to nuclear motion. We find a clear correlation between diffusion constant and quantum delocalization of the exciton. In materials featuring some of the highest diffusion lengths to date, e.g. the non-fullerene acceptor Y6, the exciton propagates via a transient delocalization mechanism, reminiscent to what was recently proposed for charge transport. Yet, the extent of delocalization is rather modest, even in Y6, and found to be limited by the relatively large exciton reorganization energy. On this basis we chart out a path for rationally improving exciton transport in organic optoelectronic materials.

Evaluating the role of energetic disorder and thermal activation in exciton transport

2016 ◽  
Vol 4 (16) ◽  
pp. 3437-3442 ◽  
Author(s):  
S. Matthew Menke ◽  
Russell J. Holmes
Keyword(s):  
Organic Semiconductors ◽  
Thermal Activation ◽  
Diffusion Length ◽  
Temperature Dependent ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length ◽  
Exciton Transport ◽  
Energetic Disorder ◽  
Boron Subphthalocyanine

Temperature dependent measurements of the exciton diffusion length (LD) are performed for three archetypical small-molecule, organic semiconductors: aluminum tris-(8-hydroxyquinoline) (Alq3), dicyanovinyl-terthiophene (DCV3T), and boron subphthalocyanine chloride (SubPc).

Nanostructured Organic–Inorganic Hybrid Solar Cells

MRS Bulletin ◽  
2009 ◽  
Vol 34 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Michael D. McGehee
Keyword(s):  
Solar Cells ◽  
Organic Semiconductors ◽  
Charge Carriers ◽  
Hybrid Solar Cells ◽  
Electron Hole ◽  
Inorganic Hybrid ◽  
Oxide Electrodes ◽  
Exciton Transport ◽  
Ordered Nanostructures ◽  
Bound Electron

AbstractWhen light is absorbed in organic semiconductors, bound electron–hole pairs known as excitons are generated. The electrons and holes separate from each other at an interface between two semiconductors by electron transfer. It is advantageous to form well-ordered nanostructures so that all of the excitons can reach the interface between the two semiconductors and all of the charge carriers have a pathway to the appropriate electrode. This article discusses charge and exciton transport in organic semiconductors, as well as the opportunities for making highly efficient solar cells and for using carbon nanotubes to replace metal oxide electrodes.

scholarly journals Modeling the Influence of Correlated Molecular Disorder on the Dynamics of Excitons in Organic Molecular Semiconductors

2018 ◽  
Author(s):  
Chee Kong Lee ◽  
Liang Shi ◽  
Adam Willard
Keyword(s):  
Organic Semiconductors ◽  
Dynamic Properties ◽  
Negative Influence ◽  
Frenkel Exciton ◽  
Spatial Correlations ◽  
Exciton Model ◽  
Molecular Systems ◽  
Exciton Transport ◽  
Energetic Disorder ◽  
Molecular Semiconductors

<div>In this Letter, we investigate the role of correlated molecular disorder on the dynamics of excitons in oligothiophene-based organic semiconductors. We simulate exciton dynamics using the Frenkel exciton model and we derive parameters for this model so that they reflect the specific characteristics of all-atom molecular systems. By systematically modifying the parameters of the Frenkel exciton model we isolate the influence of spatial and temporal molecular correlations on the dynamics of excitons in these systems. We find that the molecular fluctuations inherent to these systems exhibit long-lived memory effects, but that these effects do not significantly influence the dynamic properties of excitons. We also find that excitons can be sensitive to the molecular-scale spatial correlations, and that this sensitivity grows with the amount of energetic disorder within the material. We conclude that control over spatial correlations can mitigate the negative influence of disorder on exciton transport. </div>

scholarly journals Modeling the Influence of Correlated Molecular Disorder on the Dynamics of Excitons in Organic Molecular Semiconductors

2018 ◽  
Author(s):  
Chee Kong Lee ◽  
Liang Shi ◽  
Adam Willard
Keyword(s):  
Organic Semiconductors ◽  
Dynamic Properties ◽  
Negative Influence ◽  
Frenkel Exciton ◽  
Spatial Correlations ◽  
Exciton Model ◽  
Molecular Systems ◽  
Exciton Transport ◽  
Energetic Disorder ◽  
Molecular Semiconductors

<div>In this Letter, we investigate the role of correlated molecular disorder on the dynamics of excitons in oligothiophene-based organic semiconductors. We simulate exciton dynamics using the Frenkel exciton model and we derive parameters for this model so that they reflect the specific characteristics of all-atom molecular systems. By systematically modifying the parameters of the Frenkel exciton model we isolate the influence of spatial and temporal molecular correlations on the dynamics of excitons in these systems. We find that the molecular fluctuations inherent to these systems exhibit long-lived memory effects, but that these effects do not significantly influence the dynamic properties of excitons. We also find that excitons can be sensitive to the molecular-scale spatial correlations, and that this sensitivity grows with the amount of energetic disorder within the material. We conclude that control over spatial correlations can mitigate the negative influence of disorder on exciton transport. </div>

Energetic Control of Redox-Active Polymers Towards Safe Organic Bioelectronic Materials

2019 ◽  
Author(s):  
Alexander Giovannitti ◽  
Reem B. Rashid ◽  
Quentin Thiburce ◽  
Bryan D. Paulsen ◽  
Camila Cendra ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Organic Semiconductors ◽  
Side Reaction ◽  
Semiconducting Polymers ◽  
Side Reactions ◽  
Redox Active ◽  
Donor Acceptor ◽  
Electrochemical Devices ◽  
Biological Environment ◽  
Device Operation

<p>Avoiding faradaic side reactions during the operation of electrochemical devices is important to enhance the device stability, to achieve low power consumption, and to prevent the formation of reactive side‑products. This is particularly important for bioelectronic devices which are designed to operate in biological systems. While redox‑active materials based on conducting and semiconducting polymers represent an exciting class of materials for bioelectronic devices, they are susceptible to electrochemical side‑reactions with molecular oxygen during device operation. We show that this electrochemical side reaction yields hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), a reactive side‑product, which may be harmful to the local biological environment and may also accelerate device degradation. We report a design strategy for the development of redox-active organic semiconductors based on donor-acceptor copolymers that prevent the formation of H<sub>2</sub>O<sub>2</sub> during device operation. This study elucidates the previously overlooked side-reactions between redox-active conjugated polymers and molecular oxygen in electrochemical devices for bioelectronics, which is critical for the operation of electrolyte‑gated devices in application-relevant environments.</p>

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