A method of manufacturing a composition with improved quantum yield, containing at least these steps: a/ manufacturing a mixture by at least these steps: 1/ providing a semiconducting light emitting nanoparticle, 2/ adding a macromolecular compound comprising at least an anchoring group; 3/ adding an organic additive, and b/ subjecting the mixture from step a/ to irradiation with light of a wavelength in the range of 300 to 600 nm having an intensity in the range of 0.025 to 1 W/cm2 to obtain the composition; wherein the organic additive is defined by formula (Ia): M-(X—Y)2, wherein M is a divalent metal ion, X is a hydrocarbon chain, and Y is a functional group.