Tailored Electronic Structure and Optical Properties of Conjugated Systems through Aggregates and Dipole鈥揇ipole Interactions
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- 作者：Young Il Park ; Cheng-Yu Kuo ; Jennifer S. Martinez ; Young-Shin Park ; Olena Postupna ; Andriy Zhugayevych ; Seungho Kim ; Jongwook Park ; Sergei Tretiak ; Hsing-Lin Wang
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2013
- 出版时间：June 12, 2013
- 年：2013
- 卷：5
- 期：11
- 页码：4685-4695
- 全文大小：804K
- 年卷期：v.5,no.11(June 12, 2013)
- ISSN：1944-8252
文摘
A series of PPVO (p-phenylene vinylene oligomer) derivatives with functional groups of varying electronegativity were synthesized via the Horner鈥揥adsworth鈥揈mmons reaction. Subtle changes in the end group functionality significantly impact the molecular electronic and optical properties of the PPVOs, resulting in broadly tunable and efficient UV absorption and photoluminescence spectra. Of particular interest is the NO2-substituted PPVO which exhibits photoluminescence color ranging from the blue to the red, thus encompassing the entire visible spectrum. Our experimental study and electronic structure calculations suggest that the formation of aggregates and strong dipole鈥揹ipole solute鈥搒olvent interactions are responsible for the observed strong solvatochromism. Experimental and theoretical results for the NH2-, H-, and NO2-substituted PPVOs suggest that the stabilization of ground or excited state dipoles leads to the blue or red shift of the optical spectra. The electroluminescence (EL) spectra of H-, COOH-, and NO2-PPVO have maxima at 487, 518, and 587 nm, respectively, in the OLED device. This trend in the EL spectra is in excellent agreement with the end group-dependent PL spectra of the PPVO thin-films.