Charge Carrier Generation Mechanism for Titanyl Phthalocyanine by the Analysis of Time-resolved Fluorescence Emission

用单光子计数技术测量了酞菁颜料的时间分辨荧光光谱和寿命。单光子计数系统由染料激光器、光电倍增管、单色仪、信号处理器和个人计算机系统组成。在玻璃基板上涂覆了分散在粘结剂聚合物中的α、x型无金属酞菁颜料、α、β、epsilon型铜酞菁颜料和阿尔法型钛基酞菁颜料。采用列车升华提纯技术对铜系酞菁颜料进行提纯处理，并利用该系统获得了样品在He-Ne激光照射下的荧光光谱。酞菁类颜料在近红外波段发射荧光，波长范围从800 nm到900 nm。X-型无金属酞菁颜料的荧光强度比其他颜料大。实验结果没有得到荧光强度与光载流子产生效率之间的关系。利用单光子计数技术测量了x型无金属酞菁颜料的荧光发射瞬变。样品在610 nm波长的染料激光照射下的荧光寿命约为2微秒。这一寿命比溶解在有机溶液中的酞菁分子的寿命要长。认为该荧光寿命对应于激子在酞菁颜料中的扩散。

Time-resolved fluorescence spectra and lifetimes of phthalocyanine pigments were measured by using the single photon counting technique. The single photon counting system were consisting of dye laser, photomultiplier, monochrometer, signal processor and personal computer system. alpha-, x-type Metal-free phthalocyanine pigments, alpha-, beta-, epsilon-type copper-phthalocyanine pigments and alpha-type titanyl phthalocyanine pigment dispersed in a binder polymer were coated on the glass substrate. Copper phthalocyanine pigments were used after purification process by the train sublimation technique.The fluorescence spectra for the samples exposed to He-Ne laser light were obtained by this system. Phthalocyanine pigments emitted fluorescence in the near infrared wavelength range from 800nm to 900nm. The intensity of fluorescence for x-type metal-free phthalocyanine pigment was larger than that of other pigments. The relation between the intensity of fluorescence and photocarrier generation efficiency was not obtained from this experimental results.The transient of fluorescence emission for x-type metal-free phthalocyanine pigment was measured by using the singly photon counting technique. The life time of fluorescence for the sample exposed to 610nm wavelength of dye laser light was about 2 mu seconds. This life time is larger than that of phthalocyanine molecules dissolved in the organic solution. It is considered that this life time of fluorescence corresponds to the diffusion of exciton in phthalocyanine pigment.