The invention provides a lighting device comprising (i) a light source configured to generate light source light, and (ii) a light converter configured to convert at least part of the light source light into visible converter light, wherein the light converter comprises a polymeric host material with light converter nanoparticles embedded in the polymeric host material, wherein the polymeric host material is based on radical polymerizable monomers, and wherein the polymeric host material contains equal to or less then 5 ppm radical initiator based material relative to the total weight of the polymeric host material.