Full-Color Emission From In2S3 and In2S3:Eu3+ Nanoparticles

Blue (425 nm) and green (510 nm) emission is observed from In2S3 nanoparticles which are synthesized using a novel method. Both the blue and green emissions have large Stokes shifts of 62 and 110 nm, respectively. Excitation with longer wavelength photons causes the blue emission to shift to longer wavelength while the green emission wavelength remains unchanged. The lifetimes of both green and blue emissions are similar to reported values for excitonic recombination. When doped with Eu3+, in addition to the broad blue and green emissions, a red emission at 615 nm attributed to Eu3+ is observed. Temperature dependences on nanoparticle thin films indicate that with increasing temperature, the green emission wavelength remains constant, however, the blue emission shifts toward longer wavelengths. Based on these observations, the blue emission is attributed to exciton recombination and the green emission to Indium interstitial defects. These nanoparticles show full-color emission with high efficiency, fast lifetime decays, good stability, and are relatively simple to prepare thus making them a new type of phosphor with potential applications in lighting, flat-panel displays, and communications