Transition from dispersive to non-dispersive transport as seen by TSC in PVK/PC mixture

TOF (time-of-flight) measurements were carried out for a poly(N-vinyl carbazole)/polycarbonate mixture in the temperature range 220-370 K. Around 250 K a transition from dispersive to non-dispersive (D-ND) hole transport with increasing temperature was found to occur. Comparison of TSC (thermally stimulated current), TL (thermoluminescence), isothermal TOF, and thermally stimulated TOF indicates that the dispersive transport results from frozen-in energetic disorder rather than from multiple trapping. In simultaneous TL and TSC measurements no evidence of effective trapping in the temperature range of the D-ND transition was found. The field- and thickness dependent TSC peak in this temperature range is not the 'detrapping peak' but rather is equivalent to the thermally stimulated TOF signal.<
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