Transition from dynamic to static disorder in one-dimensional organic semiconductors

2009 ◽  
Vol 131 (1) ◽  
pp. 014703 ◽  
Author(s):  
Alessandro Troisi ◽  
David L. Cheung
Keyword(s):  
Organic Semiconductors ◽  
Static Disorder ◽  
One Dimensional

Recent Advance in 1-D Organic Semiconductors for Waveguide Applications

2019 ◽  
Vol 16 (3) ◽  
pp. 244-252 ◽  
Author(s):  
Rong Zhang ◽  
Xiaobei Jin ◽  
Xuwen Wen ◽  
Qi Chen
Keyword(s):  
Small Molecules ◽  
Organic Semiconductors ◽  
Recent Progress ◽  
Optoelectronic Properties ◽  
Size Reduction ◽  
One Dimensional ◽  
Good System ◽  
Ordered Nanostructures ◽  
Morphology Influence

One dimensional (1-D) micro-/nanostructures provide a good system to investigate the dependence of various properties on dimensionality and size reduction, especially in optoelectronic field. Organic conjugates including small molecules and polymers exhibit good optoelectronic properties and are apt to assemble into ordered nanostructures with well-defined shapes, tunable sizes and defect-free structures. In this review, we focus on recent progress of 1-D organic semiconductors for waveguide applications. Fabrication methods and materials of 1-D organic semiconductors are introduced. The morphology influence on the properties is also summarized.

Ultrafast Photoconductivity in Organic Semiconductors

2006 ◽  
Vol 935 ◽  
Author(s):  
Oksana Ostroverkhova ◽  
David G. Cooke ◽  
Frank A. Hegmann ◽  
John E. Anthony ◽  
Vitaly Podzorov ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Organic Semiconductors ◽  
Carrier Mobility ◽  
Charge Carrier Mobility ◽  
Brick Wall ◽  
One Dimensional ◽  
Organic Molecular Crystals ◽  
Charge Carrier Dynamics ◽  
Transient Photoconductivity ◽  
Comprehensive Study

ABSTRACTWe present comprehensive study of ultrafast charge carrier dynamics in a variety of organic molecular crystals. In all samples, we observed sub-picosecond charge photogeneration and band-like transport, characterized by (i) an increase in charge carrier mobility as the temperature decreases in a wide temperature range of at least 20 K – 300 K and (ii) mobility anisotropy in the a-b plane of the crystals. The temperature dependence of the decay dynamics of the transient photoconductivity reveals the presence of shallow trapping sites in herring-bone-type-structured crystals (such as pentacene (Pc), tetracene (Tc), and rubrene (Rub)), while such traps are apparently absent in “brick-wall”-type crystals (such as functionalized pentacene (FPc)). We also report on the measurements of the charge carrier mobility anisotropy in the a-b plane of two types of FPc single crystals. Anisotropies of approximately 3.5 and 11.6 were obtained in the crystals characterized by crystal structures favoring two-dimensional and one-dimensional charge transport, respectively, consistent with the degree of π-overlap along different directions in the crystals.

Research on Charge Transport in One-Dimensional Organic Semiconductors Material

2012 ◽  
Vol 531 ◽  
pp. 231-234 ◽  
Author(s):  
Wen Liu
Keyword(s):  
Electric Field ◽  
Charge Transport ◽  
Organic Semiconductors ◽  
Electric Fields ◽  
One Dimensional ◽  
Organic Semiconductor Materials ◽  
Insulator Metal Transition ◽  
The Family ◽  
High Electric Fields ◽  
Ssh Model

1D conjugated polymers belong to the family of organic semiconductor materials, in which the charge carriers are polarons or bipolarons. Charge transport in 1D organic semiconductors in the presence of high electric fields is studied within the SSH model. It is found that under a sufficiently high electric field, the polaron is dissociated into free-like electron. The electron performs Bloch oscillation (BO) in the organic semiconductors. By enhancing the electric field, BO will be destroyed and electrons can transit from the valence band to the conduction band, which is Zener tunneling in organic semiconductors. The results also indicate a field-induced insulator-metal transition.

scholarly journals A universal Urbach rule for disordered organic semiconductors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christina Kaiser ◽  
Oskar J. Sandberg ◽  
Nasim Zarrabi ◽  
Wei Li ◽  
Paul Meredith ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Organic Solar Cells ◽  
Disordered Systems ◽  
Urbach Energy ◽  
Phonon Scattering ◽  
Exponential Tail ◽  
Temperature Dependent ◽  
Static Disorder ◽  
Line Shapes ◽  
Gaussian Density

AbstractIn crystalline semiconductors, absorption onset sharpness is characterized by temperature-dependent Urbach energies. These energies quantify the static, structural disorder causing localized exponential-tail states, and dynamic disorder from electron-phonon scattering. Applicability of this exponential-tail model to disordered solids has been long debated. Nonetheless, exponential fittings are routinely applied to sub-gap absorption analysis of organic semiconductors. Herein, we elucidate the sub-gap spectral line-shapes of organic semiconductors and their blends by temperature-dependent quantum efficiency measurements. We find that sub-gap absorption due to singlet excitons is universally dominated by thermal broadening at low photon energies and the associated Urbach energy equals the thermal energy, regardless of static disorder. This is consistent with absorptions obtained from a convolution of Gaussian density of excitonic states weighted by Boltzmann-like thermally activated optical transitions. A simple model is presented that explains absorption line-shapes of disordered systems, and we also provide a strategy to determine the excitonic disorder energy. Our findings elaborate the meaning of the Urbach energy in molecular solids and relate the photo-physics to static disorder, crucial for optimizing organic solar cells for which we present a revisited radiative open-circuit voltage limit.

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