Solvent Effects on Electronic Structures and Chain Conformations of α-Oligothiophenes in Polar and Apolar Solutions

2007 ◽  
Vol 111 (16) ◽  
pp. 4128-4136 ◽  
Author(s):  
Suci Meng ◽  
Jing Ma ◽  
Yuansheng Jiang
Keyword(s):  
Solvent Effects ◽  
Electronic Structures ◽  
Chain Conformations

Electronic structures and solvent effects of unsymmetrical neo-confused porphyrin: DFT and TDDFT–IEFPCM investigations

2016 ◽  
Vol 1081 ◽  
pp. 18-24 ◽  
Author(s):  
Hong-Yu Cao ◽  
Duan-Hui Si ◽  
Qian Tang ◽  
Xue-Fang Zheng ◽  
Ce Hao
Keyword(s):  
Solvent Effects ◽  
Electronic Structures

Electronic structures of carbazole and indole and the solvent effects on the electronic spectra

1964 ◽  
Vol 2 (2) ◽  
pp. 158-167 ◽  
Author(s):  
Noboru Mataga ◽  
Yoshikazu Torihashi ◽  
Kiyoshi Ezumi
Keyword(s):  
Solvent Effects ◽  
Electronic Spectra ◽  
Electronic Structures

Effect of Solvents on Controlling the Photophysical Properties of Poly[2-Methoxy-5-(2’-Ethylhexyloxy)-1,4-Phenylenevinylene] (MEH-PPV) Nanoparticle

2017 ◽  
Vol 16 ◽  
pp. 56-59
Author(s):  
Ruttayapon Potai ◽  
Rakchart Traiphol
Keyword(s):  
Absorption Spectra ◽  
Solvent Effects ◽  
Conjugated Polymer ◽  
Photophysical Properties ◽  
Conjugation Length ◽  
Simple Method ◽  
Chain Packing ◽  
Solvent Interactions ◽  
Effect Of Solvents ◽  
Chain Conformations

Abstract. This study focuses on detailed investigation of solvent effects on controlling photophysical properties of poly [2-methoxy,5-(2’-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) nanoparticles prepared by using reprecipitation techniques. In this work, the MEH-PPV polymer is dissolved in various solvents, including chlorobenzene (CRB), toluene (TOL) and pyridine (PYR). The polymers in solutions adopt different conformations (i.e. collapsed or extended coils), depending on local polymer-solvent interactions. The differences of chain conformations cause the variations of chain packing within the nanoparticles. The majority of nanoparticles exhibit diameter of about 65-70 nm. The photophysical properties of MEH-PPV nanoparticles varied with type of solvents. The absorption spectra of nanoparticles exhibit a broad pattern with a long red tail at about 550 nm, indicating the formation of inter-and/or intrachain aggregates within the nanoparticles. However, the nanoparticle from TOL system shows blueshift of λmax, corresponding to the decrease of conjugation length due to the existence of collapsed coil. The photoluminescence (PL) spectra of MEH-PPV nanoparticles show consistent result with the shift of λmax to about 590 nm and vibronic shoulder at about 640 nm. The PL patterns vary with the type of solvents. In addition, the PL patterns depend on the variations of excitation wavelengths. These discrepancies indicated the variation of chain conformation and degree of aggregation within the nanoparticles. Our results demonstrate the simple method to prepare the conjugated polymer nanoparticle with different photophysical properties by changing solvents.

The Nature of Oxide Surfaces: Topographic and Electronic Structure

1993 ◽  
Vol 51 ◽  
pp. 966-967
Author(s):  
Dawn A. Bonnell ◽  
Yong Liang
Keyword(s):  
Transition Metal Oxides ◽  
Electronic Structures ◽  
Recent Progress ◽  
Spatial Localization ◽  
Level Of Detail ◽  
Scanning Tunneling ◽  
Oxide Surfaces ◽  
Tunneling Microscopy ◽  
Considerable Effort ◽  
Complete Understanding

Recent progress in the application of scanning tunneling microscopy (STM) and tunneling spectroscopy (STS) to oxide surfaces has allowed issues of image formation mechanism and spatial resolution limitations to be addressed. As the STM analyses of oxide surfaces continues, it is becoming clear that the geometric and electronic structures of these surfaces are intrinsically complex. Since STM requires conductivity, the oxides in question are transition metal oxides that accommodate aliovalent dopants or nonstoichiometry to produce mobile carriers. To date, considerable effort has been directed toward probing the structures and reactivities of ZnO polar and nonpolar surfaces, TiO2 (110) and (001) surfaces and the SrTiO3 (001) surface, with a view towards integrating these results with the vast amount of previous surface analysis (LEED and photoemission) to build a more complete understanding of these surfaces. However, the spatial localization of the STM/STS provides a level of detail that leads to conclusions somewhat different from those made earlier.

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