NOVELTY - Composition (I) (102) comprises one or more colloidal metal nanoparticles, where (I) is disposed on a substantially transparent substrate (104) of a photovoltaic cell (100).    USE - (I) is useful in a photovoltaic cell (claimed), which is useful to make solar panels, solar modules or photovoltaic arrays, and are useful in electrical systems, optical systems, consumer electronics, industrial or military electronics, wireless systems and space applications.    ADVANTAGE - The nanoparticles in the photovoltaic cell, provide increased scattering and also wavelength shifting to increase the efficiency of the photovoltaic cells. (I) can simultaneously increase the solar response of both blue and near UV photons, as well as red and near-infrared photons, of the solar spectrum, for increasing the efficiency of the photovoltaic cell. The nanoparticles provide both conversion of blue photons to longer wavelengths and scattering of red photons. The colloidal metal nanoparticle do not require the use of chemical vapor deposition (CVD) or physical vapor deposition (PVD) for deposition, and also do not require the use of elevated temperatures, for reducing the time, cost and complexity of formation of (I).    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) the preparation of (I) comprising one or more colloidal metal nanoparticles on a substantially transparent substrate of a photovoltaic cell, comprising: (a) providing a substantially transparent substrate; and (b) disposing a composition comprising a dielectric material and colloidal metal nanoparticles on the substantially transparent substrate;    (2) a photovoltaic cell comprising: a substantially transparent substrate; and a composition comprising one or more colloidal metal nanoparticles disposed on the substrate; and    (3) a method of preparing a photovoltaic cell, comprising: (a1) providing a substantially transparent substrate; (b1) disposing a front contact electrode on the substantially transparent substrate; (c1) disposing a photovoltaic module semiconductor on the front contact electrode (106); (d1) disposing a back contact electrode (110) on the photovoltaic module semiconductor; and (e1) disposing a composition comprising one or more colloidal metal nanoparticles, on the substantially transparent substrate of the photovoltaic cell, opposite the front contact electrode.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of multiple layers of a nanoparticle composition.    Photovoltaic cell (100)    Composition (102)    Transparent substrate (104)    Front contact electrode (106)    Back contact electrode. (110)