Study of charge transport in P3HT:SiNW-based photovoltaic devices

Hybrid devices based on silicon nanowires (SiNWs) dispersed in a conjugated polymer poly(3-hexylthiophene) P3HT thin films have been realized. The carrier transport mechanism in inorganic/organic hybrid nancocomposites consisting of SiNW dispersed in P3HT layer was investigated by using I?CV characteristics and impedance spectroscopy measurements. The conduction mechanism in these hybrid nanocomposites has been identified to be thermionic emission at the interfaces. The electrical parameters of the structure have been investigated by modelization of the I?CV characteristics using an electrical equivalent circuit and have been extracted for the different SiNW volume ratios. The barrier height, the series resistance and the shunt resistance values of the diodes have been calculated as about 0.9 eV, several k?? and several M??, respectively. The diode behaves as non-ideal one because of the series resistance and the Donor/Acceptor interface layer. The impedance spectroscopy study, in the frequency range 100 Hz?C100 kHz, shows a typical behavior of disordered materials and indicative of a hopping transport in the investigated temperature range. The dc conductivity follows the Arrhenius law with an activation energy transition from 8.4 to 55.8?meV at about 294 K.