Polymer film materials based on polyethylene containing between 0.5% and 1.0% by wt. nanocrystalline silicon (ncSi) with excellent strength properties have been produced. Specimens of ncSi with a mean core diameter of 7-10 nm were synthesised using plasma chemistry methods and laser-induced breakdown of monosilane. Spectral studies indicate an almost total (up to ~95%) absorption of UV radiation by films 85 microns thick in the 200-400 nm area with a 1.0% by wt. ncSi content in them. Using the method of full-profile modelling of X-ray diffraction patterns, and assuming that the crystallites are spherical in shape and have a log-normal distribution, the particle size distribution density functions in the initial powders and polymer films containing immobilised silicon nano展开▼