Effect of synthesis temperature on the charge transport properties of poly(3-methylthiophene) devices

Abstract

Low temperature-dependent I-V measurement was adopted to investigate an insight into the effect of synthesis temperature on the field and temperature-dependent charge transport properties of electrochemically polymerized poly(3-methylthiophene) devices. Devices having different doping levels were fabricated at two different temperatures, one at room temperature (25oC) and another at a lower temperature (5oC). The transport mechanism in the devices were studied in the temperature range 40 K to 300 K. Our studies revealed that trap controlled space charge limited conduction (TCSCLC) mechanism dominated the transport mechanism at higher temperature(T>200K) and changed to field dependent mobility model at lower temperature(T<200K). It was observed that the synthesis temperature influenced the transport parameters. Devices prepared at low temperature showed an increase in resistivity and a corresponding decrease in the charge carrier mobility compared to those prepared at high temperature. Moreover, the distribution of the trap states in the devices was also affected by the synthesis temperature, with devices fabricated at low temperature exhibiting a wider trap state distribution.