NOVELTY - A wavelength conversion film comprises optically transparent polymer matrix and fluorescent composite particles which have diameter of 5 nm to 1 mu m, are dispersed in polymer matrix, and contain inorganic oxide matrix (101) and chromophore (100). The chromophore is embedded into the inorganic oxide matrix and converts incoming photons of a particular wavelength to a different wavelength.    USE - A wavelength conversion film for solar energy device and window for a greenhouse (all claimed).    ADVANTAGE - The wavelength conversion film improves the solar harvesting efficiency of solar energy conversion devices and exhibits significantly enhanced photostability and strong resistance to peroxide decomposition due to the chromophores which are embedded into an inorganic matrix. The growth rate and fruit yield of a plant are increased by 5-30% relative to a plant not exposed to light which is filtered by the wavelength conversion film.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) improvement of solar harvesting efficiency of a solar energy conversion device which involves incorporating the wavelength conversion film into the solar energy conversion device;    (2) increasing the growth rate of a plant which involves exposing a plant to light which is filtered through the wavelength conversion film;    (3) increasing the fruit yield of a plant which involves exposing a plant to light which is filtered through the wavelength conversion film;    (4) compound of formula (I);    (5) compound of formulae (II-a) or (II-b);    (6) compound of formula (E);    (7) compound of formula (G); and    (8) compound selected from group of formula (J).    -C(R4'')(R5'')(R6'')=1-12C alkyl or 3-12C cycloalkyl;    R'=-CaH2a-Rasterisk, -CaH2a-O-R1', -CaH2a-COR1', or -CaH2a-OCOR1';    a=1-20;    Rasterisk=optionally substituted 3-10C cycloalkyl, Ph, or isoindolin-1,3-dion-2-yl, or R1'';    R1'=H or Rasterisk;    R1''=CbHcNdOe;    b=1-7;    c=3-18;    d=0 or 1;    e=1-4;    L2=-CfH2f-; and    f=1-8.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of a fluorescent composite particle in which the chromophore is embedded inside the inorganic oxide matrix.    Chromophore (100)    Inorganic oxide matrix (101)