Exciton diffusion length and concentration of holes in MEH-PPV polymer using the surface voltage and surface photovoltage methods

► Surface photovoltage was used to find exciton diffusion length in MEH-PPV polymer. ► Kelvin probe force microscopy yielded the work function and free holes concentration. ► Due to traps the concentration of free holes was lower than that of ionized states. ► Band diagram of ITO/MEH-PPV contact was found.