TRAP-FREE CHARGE TRANSPORT IN POLYMERS, WITH TUNABLE MOBILITIES

Some insulating polymers with the ability to transport injected or photogenerated charge carriers also display useful features which until recently were believed to be unobtainable in organic compounds and are difficult or sometimes even impossible to achieve with classical solid state materials. Among these features are: (i) the existence of perfectly ohmic contacts with adjacent electrodes, (ii) trap-free non-dispersive transport with high carrier range (mutau) far exceeding 10(-5) cm2/V, (iii) the ability to control drift mobilities from less than 10(-10) to about 10(-1) cm2/V s without introducing deep traps and without increasing conductivity, and (iv) no detectable degradation of transport characteristics when space-charge-limited currents (SCLC) are passed through the specimens for long periods of time. These features are briefly reviewed and discussed for representative materials.