摘要
用量子化学的 AM1和 EHMACC/CO方法计算 PPV,MEH-PPV和 CN-PPV的电子和能带结构 ,讨论了烷氧基 (— OR)和氰基 (— CN)侧基取代对 PPV类电致发光聚合物光电特性的影响 .计算结果表明 :给电子基团 (—OR)取代使聚合物的 HOCO(最高占据晶体轨道 )能级升高 ,电离势减小 ,而吸电子基团 (— CN)取代使 LUCO(最低未占据晶体轨道 )能级降低 ,电子亲和势增大 ,两者都使聚合物能隙降低 ,同时使聚合物的导电类型由 PPV的 p型转变成 CN-PPV的 n和 p兼容型 .该结果解释了 MEH-PPV和 CN-PPV光谱的红移及 CN-PPV高的电致发光效率 ,为设计新型高效的 PPV类电致发光聚合物提供了理论基础 .
The electronic properties and energy band structures of PPV, MEH-PPV and CN-PPV were calculated by quantum chemistry method, AM1 and EHMACC/CO, respectively. The influence of photo-electricity on PPV-like electroluminescent polymers substituted by alkyloxy(-OR) and cyano(-CN) were discussed. The result indicates that HOCO level(highest occupied crystal orbital) of polymer is raised by electron-donor(-OR) substitutions and the ionization potentials is decreased, while LUCO level(lowest unoccupied crystal orbital) is lowered by the electron-acceptor(-CN) substitution and electron affinities is increased. The band gap of polymer is decreased in both cases. At the same time, conducting type is changed from p type of PPV to n and p compatibility type of CN-PPV. The red shift of spectrum of MEH-PPV and CN-PPV and the higher electroluminescence efficiency of CN-PPV were explained. Our calculation is significant for designing new type PPV-like polymers with a high electroluminescence efficiency.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第12期2340-2343,共4页
Chemical Journal of Chinese Universities
基金
吉林省自然科学基金 (批准号 :2 0 0 2 6 18)
国家重点实验室访问学者基金 (批准号 :教技司 1999-15 3)资助
