Covalent layer-by-layer assembly of conjugated polymers and CdSe nanoparticles: Multilayer structure and photovoltaic properties

Hybrid thin films of conjugated polymers and CdSe nanoparticles have been fabricated by using a layer-by-layer (LbL) approach driven by covalent coupling reactions. This method permits facile covalent crosslinking of the polymer/nanoparticle interlayers in common organic solvents, which provides a general route for preparing robust and uniform functional thin films. The deposition process is linearly related to the number of bilayers as monitored by UV-vis absorption spectroscopy and ellipsometry. Characterization of the multilayer structures has been carried out by fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), and grazing-angle Fourier-transform infrared spectroscopy (FTIR). Techniques such as atomic force microscopy (AFM) and scanning electron microscopy (SEM) have also been used. A preliminary application of the hybrid films in the development of organic photovoltaics is presented. Upon illumination with white light at 10 m W cm(-2), the self assembled multilayer films exhibit steady photocurrent responses with an overall optical-to-electrical power conversion efficiency of 0.71%.