Alternated Quinoid/Aromatic Units in Terthiophenes Building Blocks for Electroactive Narrow Band Gap Polymers. Extended Spectroscopic, Solid State, Electrochemical, and Theoretical Study

2005 ◽  
Vol 109 (35) ◽  
pp. 16616-16627 ◽  
Author(s):  
Juan Casado ◽  
Rocío Ponce Ortiz ◽  
Mari Carmen Ruiz Delgado ◽  
Víctor Hernández ◽  
Juan T. López Navarrete ◽  
...  
Keyword(s):  
Solid State ◽  
Band Gap ◽  
Theoretical Study ◽  
Narrow Band ◽  
Building Blocks

Combined Spectroscopic and Theoretical Study of Narrow Band Gap Heterocyclic Co-oligomers Containing Alternating Aromatic Donor ando-Quinoid Acceptor Units

2004 ◽  
Vol 108 (8) ◽  
pp. 2516-2526 ◽  
Author(s):  
Mari Carmen Ruiz Delgado ◽  
Víctor Hernández ◽  
Juan T. López Navarrete ◽  
Shoji Tanaka ◽  
Yoshiro Yamashita
Keyword(s):  
Band Gap ◽  
Theoretical Study ◽  
Narrow Band ◽  
Aromatic Donor

scholarly journals Phosphonate Metal-Organic Frameworks: A Novel Family of Semiconductors

2020 ◽  
Author(s):  
Konrad Siemensmeyer ◽  
Craig A. Peeples ◽  
Patrik Tholen ◽  
Bünyemin Çoşut ◽  
Gabriel Hanna ◽  
...  
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Band Gap ◽  
Narrow Band ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
One Dimensional ◽  
Metal Organic ◽  
Copper Dimers ◽  
Electrodes For Supercapacitors

<p>Herein is reported the first semiconducting and magnetic phosphonate metal-organic framework (MOF), TUB75, which contains a one-dimensional inorganic building unit composed of a zig-zag chain of corner-sharing copper dimers. The solid-state UV-Vis spectrum of TUB75 reveals the existence of a narrow band gap of 1.4 eV, which agrees well with the 1.77 eV one obtained from DFT calculations. Magnetization measurements show that TUB75 is composed of antiferromagnetically coupled copper dimer chains. Due to their rich structural chemistry and exceptionally high thermal/chemical stabilities, phosphonate MOFs like TUB75 may open new vistas in engineerable electrodes for supercapacitors. </p>

Thermoelectric Properties of the cubic AgPb10SbTe12

2003 ◽  
Vol 793 ◽  
Author(s):  
Kuei-Fang Hsu ◽  
Sim Loo ◽  
Wei Chen ◽  
Ctirad Uher ◽  
Tim Hogan ◽  
...  
Keyword(s):  
Solid State ◽  
Band Gap ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Solid State Reaction ◽  
Narrow Band ◽  
Thermoelectric Measurements

ABSTRACTAgPb10SbTe12 is one member of the cubic family of materials AgPbmSbTem+2, which adopts NaCl structure where Ag, Pb and Sb atoms occupy the Na site and Te atoms occupy the Cl site. Ingots of this compound were prepared by a solid state reaction for thermoelectric measurements. AgPb10SbTe12 is a narrow band gap semiconductor with Eg∼0.26 eV. In order to optimize the ZT of this member, compositions with deficiency of Ag and Bi-substitution were examined and found to exhibit enhanced power factor at 300 K. The Bi-substituted ingot had ZT∼0.39 at 300 K and ZT∼0.68 at 400 K. Carrier concentration and the mobility measurements are reported.

scholarly journals Phosphonate Metal-Organic Frameworks: A Novel Family of Semiconductors

2020 ◽  
Author(s):  
Konrad Siemensmeyer ◽  
Craig A. Peeples ◽  
Patrik Tholen ◽  
Bünyemin Çoşut ◽  
Gabriel Hanna ◽  
...  
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Band Gap ◽  
Narrow Band ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
One Dimensional ◽  
Metal Organic ◽  
Copper Dimers ◽  
Electrodes For Supercapacitors

<p>Herein is reported the first semiconducting and magnetic phosphonate metal-organic framework (MOF), TUB75, which contains a one-dimensional inorganic building unit composed of a zig-zag chain of corner-sharing copper dimers. The solid-state UV-Vis spectrum of TUB75 reveals the existence of a narrow band gap of 1.4 eV, which agrees well with the 1.77 eV one obtained from DFT calculations. Magnetization measurements show that TUB75 is composed of antiferromagnetically coupled copper dimer chains. Due to their rich structural chemistry and exceptionally high thermal/chemical stabilities, phosphonate MOFs like TUB75 may open new vistas in engineerable electrodes for supercapacitors. </p>

Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

2018 ◽  
Author(s):  
Sherif Tawfik ◽  
Olexandr Isayev ◽  
Catherine Stampfl ◽  
Joseph Shapter ◽  
David Winkler ◽  
...  
Keyword(s):  
Machine Learning ◽  
Band Gap ◽  
Density Functional ◽  
2D Materials ◽  
Van Der Waals ◽  
Building Blocks ◽  
Machine Learning Techniques ◽  
Interlayer Distance ◽  
Computational Screening ◽  
Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

scholarly journals Influence of surface band bending on a narrow band gap semiconductor: Tunneling atomic force studies of graphite with Bernal and rhombohedral stacking orders

2021 ◽  
Vol 5 (4) ◽  
Author(s):  
Regina Ariskina ◽  
Michael Schnedler ◽  
Pablo D. Esquinazi ◽  
Ana Champi ◽  
Markus Stiller ◽  
...  
Keyword(s):  
Band Gap ◽  
Narrow Band ◽  
Surface Band ◽  
Band Bending ◽  
Atomic Force
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