<p>The purpose of the present invention is to achieve a semiconductor nanoparticle assembly structure having high luminance, which is suppressed in decrease of the luminance even if semiconductor nanoparticles are assembled. A semiconductor nanoparticle assembly structure of the present invention comprises an inner structure which is obtained by assembling a plurality of first semiconductor nanoparticles and an outer structure which is obtained by assembling a plurality of second semiconductor nanoparticles. The first semiconductor nanoparticles have a smaller band gap than the second semiconductor nanoparticles.</p>
