Enhanced Luminescence with Fast Nanosecond Lifetime in In₂S₃:Tb³⁺ Nanophosphors

Luminescent inorganic nanoparticles have attracted large amounts of attention because of their enhanced luminescence efficiency and shortening of radiative lifetime, particularly rare earth ion doped nanophosphors that possess excellent luminescent properties as a result of their inner shell electronic transitions between the 4f–4f energy levels. Herein, we have investigated the effect of Tb 3+ content on the absorption, photoluminescence, and luminescence decay curves. The PL spectra give two emission processes, which are assigned to the intrinsic emission and the defect-related emission, respectively. Excess terbium content leads to reducing intensity of photoemission as a result of concentration quenching. The fitted lifetime values are approximately 1 ns and get shortened with the increase of Tb 3+ content, due to the increased nonradiative transition rate. UV absorption corroborates valence–conduction band transition and strong quantum size effect. The energy band gap value for Tb 3+ -doped In 2 S 3 is higher than that for the pure sample, which is in good agreement with the band structure calculation by using VASP. The In 2 S 3:Tb 3+ nanoparticles show strong quantum confinement effect, large luminescence enhancement, and fast nanosecond lifetime, thus making them a new type of phosphor with potential applications in flat-panel displays, lighting, and field-emission devices.