Photoconductivity and electronic processes in PCDTBT polymer composite with embedded CdSe nanoplatelets

The photoconductivity in thin films of a new composite based on CdSe nanoplatelets (NPLs) and PCDTBT polymer has been studied using photoconductivity temperature dependences, current-voltage and lux-ampere measurements at various temperatures and applied bias. The incorporation of 7 vol% of NPLs into the polymer blend led to an increase in photoconductivity by an order of magnitude compared to the pristine PCDTBT film in the temperature range of 310–360 K and the electric field strength above 200 V cm⁻¹. An analysis of current-voltage characteristics measured at various temperatures demonstrated that the observed increase in the photoconductivity of the composite is due to a change in the transport mechanism of nonequilibrium charge carriers with an increase in their concentration. The observed saturation of photoconductivity with increasing temperature is supposed to occur due to the increase in exciton diffusion length with temperature increasing and limited effective exciton generation area.