Effect of the concentration of the poly(3-hexylthiophene) on the electrical characteristics of diode rectifiable devices

The effect of the concentration of poly(3-hexylthiophene) (P3HT) on the electrical characteristics of diode rectifiable devices fabricated utilizing the P3HT was investigated. Atomic force microscopy images showed that the root-mean-square surface roughness of the P3HT thin films decreased with decreasing P3HT concentration. The current-voltage (I-V) characteristics of the Au/P3HT layer/indium-tin-oxide-coated glass devices showed resistance switchability. The I-V characteristics of the devices showed that the ON current at the same voltage decreased with increasing concentration and that the operating voltage of the device with a larger P3HT concentration was larger than that of the device with a smaller P3HT concentration. The diode rectifiable mode of the devices transformed from the Ohmic into the space-charge-limited current modes with increasing applied voltage.