Laser-induced nanocomposite formation for printed nanoelectronics

Us nanocrystals are formed by regioselective thermal decomposition of metal alkanethiolates in a polymer matrix by selective heating of a polystyrene foil filled with the cadmium-(bis)-thiolate precursor using focused laser beam irradiation. Us nanocrystal formation in the polymer was investigated by photoluminescence emission and excitation (PL and PLE) spectroscopy and transmission electron microscopy (TEM). The PLE spectra show a band edge at 420 run for the irradiated area, indicating the presence of nanocrystalline CdS of size of about 2-3 nm. The PL exhibits an emission band at 535 nm that is also characteristic of nanometer-sized CdS. TEM images confirm the presence and size of CdS nanoparticles. The surface temperature was estimated theoretically considering the relationships between the temperature, time and power of the laser pulses. Nanoparticle formation via laser probe is also discussed in terms of possible utilization of other probes (e.g., electrons, etc.), inducing nanocrystal formation for the realization of conducting nanowires embedded in non-conductive matrix materials useful for nanoelectronic devices or conductive plastic. (c) 2005 Elsevier B.V. All rights reserved.