Capping ligand effect on charge transfer mechanism of hybrid organic(P3HT):inorganic(PbSe) nanocomposites

In this work, we have synthesized colloidal PbSe QD´s by using two different Capping ligand Oleylamine and Oleic acid. The effective diameters of PbSe QD´s are in range of 6-9 nm. As-synthesized QD´s are characterized by X-ray diffraction to check the phase formation while its optical properties are monitored by UV-Vis spectrometer and Photoluminescence. Inorganic PbSe QD´s are dispersed in Poly (3-hexyl thiophene) polymer to make PbSe (OLA): P3HT and PbSe (OA):P3HT nanocomposites respectively. Photo stability is checked by laser induced degradation and PL Quenching experiment shows enhancement in charge transfer on varying the ligands. We found that, Oleylamine capped PbSe QD´s shows higher PL quenching and hence higher Stern volmer quenching Constant (K_sv) on account of its enhanced interaction with P3HT as compared to Oleic acid capped PbSe QD´s. This shows the effective role of capping ligands particularly Oleylamine (OLA) in enhancing the charge transfer mechanism for its potential role in Organic photovoltaics.