Charge Transport Properties of Hybrid Nanocomposites Based on Colloidal PbSe Quantum Dots in...

The synthesis of PbSe nanoparticles were carried out by colloidal route using lead acetate as starting material with Oleic acid/TOP as capping agents at the optimized growth temperature. The phase and surface analysis of oleic acid/TOP capped PbSe nanocrystallites were studied in detail in this article. Current-voltage characteristics of pristine and lead selenide quantum dots (PbSe QDs) incorporated in poly(2-methoxy,5-(2'-ethylhexyloxy)-p-phenylenevinylene (MEH-PPV) thin films have been studied at different temperatures (306-125 K) in hole only device configuration, i.e., ITO/poly(ethylene-dioxythiophene):polystyrenesulphonate (PEDOT:PSS)/MEH-PPV/Au and ITO/PEDOT:PSS/MEH-PPV:PbSe/Au. It has been found that the presence of PbSe QDs in MEH-PPV results in the modulation of the charge transport mechanism from dual conduction mechanism, i.e., trap and mobility model to only trap model. It signifies that the traps are becoming shallower due to reduction in trap density from 2×10¹⁷ to 1.2×10¹⁷ cm^-3 as well as trap energy reduces from 74 meV to 62 meV on the incorporation of PbSe QDs.