Optoelectronic properties of CdSe nanoparticles and their application to bulk hetero-junction solar cells

The CdSe nanoparticles have been synthesized by hot-injection method, and thermal annealing was used to improve the crystallinity of synthesized nanoparticles and reconstruct the surface of nanoparticles. The synthesized and annealed CdSe nanoparticles were characterized by TEM, XRD and PL spectra. After thermal annealing followed by a solvent exchange process, the CdSe nanoparticles were used to fabricate bulk hetero-junction solar cells of CdSe/P₃HT active layer. The morphology control of nanoparticle-polymer composite films was also investigated. By varying only the concentration of the binary solvent mixture, the phase separation behavior between the nanoparticles and blended polymer could well be controlled from micrometer scale to nanometer scale, yielding uniform and reproducible active layer films.