【作者】 张智；

【导师】 佟振合； 张复实；

【作者基本信息】 清华大学 ， 化学， 2008， 博士

【摘要】 二芳基乙烯基全氟环戊烯分子具有优异的热稳定性和抗疲劳性,其开环态和闭环态的光化学性质显著不同,因而被广泛应用于各种光电器件如光存储、光开关等的研究。作为一种有机半导体,二芳基乙烯化合物的开环态和闭环态的π电子共轭程度不同,从而其电离能不同,即开环态和闭环态的HOMO能级不同,一般相差0.6eV左右。本论文以光控载流子开关为研究目标,将二茂铁官能团引入到二芳基乙烯分子体系中,设计合成了两个侧链取代基含有二茂铁官能团的二茂铁-二芳基乙烯化合物,调节了二芳基乙烯分子的结构和共轭程度,使得两种状态之间的HOMO能级差异(ΔIp值)增大,成功地获得了开环态和闭环态之间ΔIp值高达0.8eV的二茂铁-二芳基乙烯(DAE-12)分子,比一般现有二芳基乙烯分子的ΔIp值提高了30%以上。用此种二芳基乙烯分子作为载流子开关,设计出含有光控载流子开关层的OLED器件,可通过光电双控来达到载流子传输“开”与“关”的调节,首次获得了完全意义上的ON-OFF载流子全开关。实验表明,在阻挡层式光控载流子开关器件的设计中,要实现完全意义上的ON-OFF全开关,必须满足两个条件:一是作为光控载流子开关层的二芳基乙烯材料,必须具备足够大的开环态和闭环态之间的HOMO能级差异(ΔIp值),在一种状态下有利于载流子的传输,在另一种状态下则可以顺利地阻挡载流子的传输;二是器件的各材料层之间的能级一定要互相匹配。量子化学计算的结果表明,大多数二芳基乙烯分子的开环态和闭环态HOMO都均匀分布在噻吩-全氟环戊烯-噻吩的分子骨架体系上,因而ΔIp值前后变化较小,绝大部分的二芳基乙烯分子的ΔIp实验值都在0.6eV左右。DAE-12分子开环态和闭环态的HOMO分布在不同的共轭体系上,因而其ΔIp实验值升高。这一计算结果说明光致变色二芳基乙烯分子的光控载流子开关分子的设计是基于ΔIp值的升高。更多还原

【Abstract】 The photochromic diarylethene compounds based on perfluoro-cyclopentene have outstanding thermal stability and fatigue resistant property. There are distinct photochemical properties between their open-ring forms and closed-ring forms, which makes them as potential candidates for optical devices such as optical memories and switches.As one of organic semiconductors, the conjugated extents of pi-electrons between the two photo-isomers of diarylethene compounds are much different, and their ionization potentials (Ip), also the energy levels of the highest occupied molecular orbital (HOMO), are much different accordingly. The value of this difference (ΔIp) is usually about 0.6 eV. To obtain higher Ip change (ΔIp) between the open-ring form and closed-ring form, ferrocene was introduced into the diarylethene compounds, which had changed the extent of conjugated effect in the target molecules. As a result, a novel diarylethene molecule (DAE-12) with higher value ofΔIp, 0.8 eV, was successfully obtained. Finally, a smart light-controlled carrier switch in an organic light emitting device based on the DAE-12 had been prepared, and a real ON-OFF carrier switch was obtained successfully.To obtain a real ON-OFF carrier in the design of light-controlled carrier switch with block layer style, two commands have to be met. firstly, the diarylethens used as block layer of light-controlled carrier switch must have large enough value ofΔIp, and then in one state the transporting of carrier is favored or is blocked in another state. Secondly, the energy levels of every layer in a designed device have to be matched each other.Quantum chemical calculations were carried out in order to investigate the photoelectric performance of our target molecules. According to the results of our quantum chemical calculations, the HOMOs are usually distributed along the thiophene-perfluorocyclopentene-thiophene skeleton of diarylethene molecule in both of the open-ring state and closed-ring state. Under this condition, the changes of HOMO distribution are relatively small, which shows the reason why values ofΔIp are usually 0.6 eV for most of diarylethene compounds. However, as far as the DAE-12 is concerned, the HOMO is distributed on its different conjugated system. The results of quantum chemical calculations would be a guidance for design, synthesis of novel molecules used in light-controlled carrier switches.更多还原