Crystal step edges can trap electrons on the surfaces of n-type organic semiconductors

Vicinal Si (001) surfaces are interesting because they are good substrates for the growth of III-V semiconductors. Spots in RHEED patterns from vicinal surfaces are split due to scattering from ordered step arrays and this splitting can be used to determine the misorientation angle, using kinematic arguments. Kinematic theory is generally regarded to be inadequate for the calculation of RHEED intensities; however, only a few dynamical RHEED simulations have been attempted for vicinal surfaces. The multislice formulation of Cowley and Moodie with a recently developed edge patching method was used to calculate RHEED patterns from vicinal Si (001) surfaces. The calculated patterns are qualitatively similar to published experimental results and the positions of the split spots quantitatively agree with kinematic calculations.RHEED patterns were calculated for unreconstructed (bulk terminated) Si (001) surfaces misoriented towards [110] ,with an energy of 15 keV, at an incident angle of 36.63 mrad ([004] bragg condition), and a beam azimuth of [110] (perpendicular to the step edges) and the incident beam pointed down the step staircase.

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

10.26434/chemrxiv.11366186.v1 ◽

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

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 (H2O2), 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 H2O2 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.

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Quantitative Image Analysis of Fractal-like Thin Films of Organic Semiconductors

10.26434/chemrxiv.6223610.v1 ◽

2018 ◽

Author(s):

Weikun Zhu ◽

Erfan Mohammadi ◽

Ying Diao

Keyword(s):

Thin Film ◽

Thin Films ◽

Image Analysis ◽

Fractal Dimension ◽

Organic Semiconductors ◽

Film Growth ◽

Electronic Device ◽

Significant Control ◽

Semiconductor Thin Films ◽

Two Parameters

Morphology modulation offers significant control over organic electronic device performance. However, morphology quantification has been rarely carried out via image analysis. In this work, we designed a MATLAB program to evaluate two key parameters describing morphology of small molecule semiconductor thin films: fractal dimension and film coverage. We then employ this program in a case study of meniscus-guided coating of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) under various conditions to analyze a diverse and complex morphology set. The evolution of morphology in terms of fractal dimension and film coverage was studied as a function of coating speed. We discovered that combined fractal dimension and film coverage can quantitatively capture the key characteristics of C8-BTBT thin film morphology; change of these two parameters further inform morphology transition. Furthermore, fractal dimension could potentially shed light on thin film growth mechanisms.

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Design and Synthesis of Two-Dimensional Covalent Organic Frameworks with Four-Arm Cores: Prediction of Remarkable Ambipolar Charge-Transport Properties

10.26434/chemrxiv.7766786.v2 ◽

2019 ◽

Author(s):

Simil Thomas ◽

Hong Li ◽

Raghunath R. Dasari ◽

Austin Evans ◽

William Dichtel ◽

...

Keyword(s):

Charge Transport ◽

Organic Semiconductors ◽

Density Functional ◽

Polymer Networks ◽

Two Dimensional ◽

Covalent Organic Frameworks ◽

X Ray Diffraction ◽

Zinc Porphyrin ◽

Design And Synthesis ◽

Predicted Values

We have considered three two-dimensional (2D) π-conjugated polymer networks (i.e., covalent organic frameworks, COFs) materials based on pyrene, porphyrin, and zinc-porphyrin cores connected via diacetylenic linkers. Their electronic structures, investigated at the density functional theory global-hybrid level, are indicative of valence and conduction bands that have large widths, ranging between 1 and 2 eV. Using a molecular approach to derive the electronic couplings between adjacent core units and the electron-vibration couplings, the three π-conjugated 2D COFs are predicted to have ambipolar charge-transport characteristics with electron and hole mobilities in the range of 65-95 cm2V-1s-1. Such predicted values rank these 2D COFs among the highest-mobility organic semiconductors. In addition, we have synthesized the zinc-porphyrin based 2D COF and carried out structural characterization via powder X-ray diffraction and surface area analysis, which demonstrates the feasability of these electroactive networks.

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Charge Injection and Transport in Organic Semiconductors

10.29363/nanoge.inform.2019.014 ◽

2019 ◽

Author(s):

Gert-Jan Wetzelaer

Keyword(s):

Organic Semiconductors ◽

Charge Injection

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Efficient Electron Injection into Organic Semiconductors Induced by Hydrogen Bonds

Proceedings of the International Display Workshops ◽

10.36463/idw.2019.oled3-4l ◽

2019 ◽

pp. 840

Author(s):

Hirohiko Fukagawa ◽

Munehiro Hasegawa ◽

Katsuyuki Morii ◽

Kazuma Suzuki ◽

Tsubasa Sasaki ◽

...

Keyword(s):

Hydrogen Bonds ◽

Organic Semiconductors ◽

Electron Injection

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Chemical Defects and Electronics States in Organic Semiconductors

10.21236/ada583048 ◽

2008 ◽

Author(s):

John E. Northrup

Keyword(s):

Organic Semiconductors

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Greater than 10 cm 2 V −1 s −1 : A breakthrough of organic semiconductors for field‐effect transistors

InfoMat ◽

10.1002/inf2.12188 ◽

2021 ◽

Author(s):

Peng Hu ◽

Xuexia He ◽

Hui Jiang

Keyword(s):

Organic Semiconductors ◽

Field Effect ◽

Field Effect Transistors

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Attaining air stability in high performing n-type phthalocyanine based organic semiconductors

Journal of Materials Chemistry C ◽

10.1039/d1tc02275j ◽

2021 ◽

Author(s):

Nathan J Yutronkie ◽

Benjamin King ◽

Owen Alfred Melville ◽

Benoit Hugo Lessard ◽

Jaclyn L Brusso

Keyword(s):

Organic Semiconductors ◽

Organic Semiconductor ◽

Strong Electron ◽

Electron Conduction ◽

High Performing ◽

Silicon Phthalocyanine

The perfluorinated analogue of silicon phthalocyanine (F2-F16SiPc) has been synthesized as a novel air-stable n-type organic semiconductor. The design of F2-F16SiPc facilitates strong electron conduction through peripheral fluorination that deepens...

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