Dependences of Thermal Behaviors on the Number of Layers in Langmuir−Blodgett Films of 2-Octadecyl-7,7,8,8-tetracyanoquinodimethane. 1. Order−Disorder Transitions in the Films Investigated by Ultraviolet−Visible and Infrared Spectroscopies
Dependences of Thermal Behaviors on the Number of Layers in Langmuir−Blodgett Films of 2-Octadecyl-7,7,8,8-tetracyanoquinodimethane. 1. Order−Disorder Transitions in the Films Investigated by Ultraviolet−Visible and Infrared Spectroscopies
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DOI：
10.1021/jp952163t
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发表时间：
1996-01
期刊：
影响因子：
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通讯作者：
Yan Wang;K. Nichogi;S. Terashita;K. Iriyama;Y. Ozaki
中科院分区：
文献类型：
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作者：
Yan Wang;K. Nichogi;S. Terashita;K. Iriyama;Y. Ozaki
用紫外可见光谱(UV−−)和红外光谱(IR)研究了2-十八基-7，7，8，8-四氰基-2，8，8-四氰基-2-甲基-2，4-氰基-2-甲基-2，4-氰基-2，5，8-四氰基-2-甲基-2-甲基-2，4-氰基-2，5，5，8-四氰基-2，5，8-四氰基-2，8，8-四氰基-2-甲基-2，5，5，5，8-四氰基-2-甲基-2-甲基-2，5，4-氰基喹甲烷(TCNQ)膜的热行为与膜层数的关系。通过UV-−-Vis光谱的基线漂移监测了LB膜的形态随温度的变化。在450−600 nm区域的基线变化表明，即使在略高于室温的情况下，单层薄膜中的磁区也会随着温度的升高而逐渐分解。相反，7层膜和11层膜中的磁畴在80℃之前是稳定的，在80℃到90℃之间经历了相当突然的崩塌。单层膜和7层膜和11层膜中磁畴结构的热行为的差异可能是由于薄膜厚度的不同，第一层和CaF2衬底之间的相互作用的影响，以及薄膜的热稳定性。
Dependences of thermal behaviors on the number of layers in Langmuir−Blodgett (LB) films of 2-octadecyl-7,7,8,8-tetracyanoquinodimethane (octadecyl-TCNQ) have been investigated for both morphological and molecular structural aspects by using ultraviolet−visible (UV−vis) and infrared (IR) spectroscopies. The temperature-dependent morphological changes have been monitored by the base-line shift in the UV−vis spectra of the LB films. The changes in the base-line in the 450−600 nm region suggest that the domains in the one-layer film decompose progressively with temperature even just above room temperature. In contrast, the domains in the seven- and 11-layer films are stable until 80 °C and undergo rather abrupt collapse between 80 and 90 °C. These differences in the thermal behaviors of the domain structure between the one-layer film and the seven- and 11-layer films may be attributed to the differences in the film thickness, the effect of the interaction between the first layer and a CaF2 substrate, and the...