Degradation of current due to charge transport in top gated P3HT-PVA organic field effect transistors

•P3HT-PVA transistors were fabricated by photolithography and plasma etching.•Source − drain current was directly proportional to channel length.•Transistors were submitted to drain current stress and degradation was observed.•Reduction in transistor response was related to reduction in charge carrier mobility.•The total charge that crossed the transistor was responsible for the degradation.

Top gate-bottom contacts transistors of Poly 3-hexylthiophene (P3HT) and cross-linked Poly Vinyl Alcohol (PVA) with different channel lengths were fabricated by standard photolithography and plasma etching. The transistors presented excellent charge mobility, high ION/IOFF and temporal stability. Drain current was directly proportional to channel length. The transistors were submitted to extended current-voltage measurements and drain current degradation was observed. Reduction in transistor response was found to be related to reduction in charge carrier mobility. Drain Current as a function of the integral charge passing through the channel was investigated. The higher the integrated source − drain current that crossed the transistor, the more prominent was the degradation. The degradation followed the same pattern and persisted indefinitely. The reasons for this behavior are discussed.