Emission and percolation of excitons in dense sensembles of quantum dots on the spherical surface

► We present a concept of two percolation thresholds of excitons: inner and external. ► We have found that ZnO quantum dots have the shape of disks in the surface of SiO2 spheres. ► The exciton system is above the percolation threshold at the surface filling factor P∼0.45.