TCNQ光电压气敏特性的量子化学研究

A Quantum Chemistry Study on Surface Photovoltage and Gas Sensitive Properties of TCNQ

7,7,8,8-四氰基对苯醌二甲烷（TCNQ）的CT复合物是良好的导电材料,具有许多超常的特性,我们曾用表面光电压技术（SPV）首次观察到TCNQ多晶内部既有施主基团又有受主基团,TCNQ与探针分子（CO,O2,No2）作用,其光电压谱发生2类不同的变化。为从理论上阐明产生不同光电压谱的原因,本文用CNDO法研究了TCNQ的电子结构及其与探针分子的相互作用,讨论了气敏特性与机理。

It is found that in the visible-ultraviolet region TCNQ has two kinds of SPY peaks. When CO was adsorpted at the center of benzene ring in the TCNQ, p1 peak disappeares and p2 slightly decreases because the transition of π→π has been impeded. When O2 or NO2 was adsorbed at nitrogen atom of terminate group in TCNQ, pz peak decreases or disappeares because the transition for lone pair of nitrogen atom was impeded. The calculation results of quantum chemistry indicate that p1 and p2 peak are associated with two kinds of different transitions.