A new series of metal-free organic dyes containing pyrene and α-cyanoacrylic acid end groups and thiophene, bithiophene, thienylbenzene or thienylfluorene Ï-linkers were synthesized and characterized by absorption, emission and electrochemical measurements. Time-dependent density functional theoretical calculations were also performed to unravel the nature of the absorption induced electronic excitations. Extension of conjugation in the Ï-linker by the incorporation of phenyl or fluorene was found to enhance the molar extinction coefficient while the use of thiophene red-shifted the absorption. The longer wavelength absorption peaks found for the dyes were attributed to ÏâÏ* transition with a contribution from the charge transfer transition which becomes prominent for the bithiophene bridged derivative. The bithiophene containing dye showed moderate overall light-to-electron conversion efficiency attributable to the favorable absorption and redox properties originating due to the presence of a bithiophene segment. The trends observed for the various dyes in the device performance were rationalized by electron-impedance spectroscopy measurements.
研究人员合成了一系列新的无
金属有机
染料,这些
染料含有
芘和δ-
氰基
丙烯酸端基以及
噻吩、
噻吩、
噻吩基苯或
噻吩基
芴链接物,并通过吸收、发射和电
化学测量对其进行了表征。此外,还进行了随时间变化的密度泛函理论计算,以揭示吸收诱导电子激发的性质。研究发现,通过加入苯基或
芴来扩展Ï-连接剂中的共轭作用可提高摩尔消光系数,而使用
噻吩则会使吸收发生红移。这些
染料的长波长吸收峰归因于ÏâÏ*转变,其中电荷转移转变的贡献在
噻吩桥联衍
生物中变得突出。含有
噻吩的
染料显示出适度的整体光-电子转换效率,这归因于
噻吩段的存在所带来的有利吸收和氧化还原特性。通过电子阻抗光谱测量,各种
染料在器件性能方面的趋势得到了合理的解释。