Nanoscale optoelectronic properties of organic p-n junction P3HT/PCBM nanoparticles hybridized with CdSe/ZnS quantum dots

Organic p-n junction nanoparticles (NPs) of p-type poly(3-hexylthiophene) (P3HT) and n-type [6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM) with approximate diameters of 80-250 nm were fabricated by a mini-emulsion method. Various concentrations of functionalized CdSe/ZnS quantum dots (QDs) were hybridized with P3HT/PCBM NPs. The photoluminescence (PL) spectra of the QDs mostly overlapped the absorption spectra of the P3HT/PCBM NPs, suggesting the activation of energy and/or charge-transfer effects. Using a high-resolution laser confocal microscope (LCM), we observed that the LCM PL intensity of a single P3HT/PCBM NP quenched with increasing QD concentration. Conducting atomic force microscopy revealed that the photocurrent of the P3HT/PCBM NP was enhanced as the QD concentration increased. After the hybridization of the P3HT/PCBM NPs with the QDs, the energy/charge-transfer effects and the charge dissociation of excitons with incident light have been more active, resulting in the increased photocurrent.