Research on Photoconductivity of Polymers under High Pressure

对两种聚合物材料：掺杂吡唑啉的聚碳酸酯(PC/Py)薄膜和聚N-乙烯基咔唑/三硝基荧光酮电荷转移络合物(PVK-TNF)进行了高达350 Mpa的光导和光吸收测试。在这两种情况下，空穴的漂移迁移率都随着压力的增加而减小，这否定了通过施加压力来减小分子间距离会导致漂移迁移率增加的简单猜测。并提出了分子链的移动性起了作用。在光电导过程中扮演一些角色。在更高的压力区。然而。漂移迁移率呈现正压力依赖的趋势。另一方面，诱导电荷总量的压力依赖关系随着压力的增加而增加，这表明光生量子产率的增加和/或通过施加压力降低了输运孔的陷阱能级。更重要的是。高压光吸收测量表明，在0.0002 eV/Mpa的压力作用下，PVK-肿瘤坏死因子样品的吸收边向低能量方向移动。

Photoconductive and photoabsorbance measurements were conducted up to 350 MPa for two kinds of polymeric materials; polycarbonate doped with pyrazoline (PC/Py) films and a charge transfer complex of poly(N-vinylcarbazole)/ trinitrofluorenone (PVK-TNF). In both cases, the drift mobility for holes revealed a decrease with increasing pressure, which deny the simple speculation that the reduction of intermolecular distance by the application of pressure would result in the increase in the drift mobility. and suggest that the mobility of molecular chains plays. some role in the photoconductive process. At much higher pressure region. however. the drift mobility showed the tendency of a positive pressure dependency. On the other hand, the pressure dependence of the total amount of induced charge showed an increase with increasing pressure, suggesting that the increase in the quantam yield for the photogeneration carries and/or the lowering in the trap energy level for the transporting holes by the application of pressure. Furthermore. a high-pressure photoabsorbance measurements showed that the absorption edge shifts toward lower energy upon the application of pressure with a rate of 0.0002 eV/MPa in PVK-TNF specimen.