Tunable White-Light Emission of Co²⁺ and Mn²⁺ Co-Doped ZnS Nanoparticles by Energy Transfer between Dopant Ions

Abstract

Fabrication of white light-emitting nanophosphors with high luminous efficacy is an urgent need for the nextgeneration lighting industry and display systems. While rare-earth ions have been frequently utilized as dopants to fabricate semiconducting and dielectric nanophosphors, the limited abundance of rare-earth elements on our planet demands a search for suitable alternatives. Here, we report the fabrication of ZnS nanoparticles co-doped with Co 2+ and Mn 2+ transition metal ions which manifest intense near-white light emission under ultraviolet excitation. While the nanophosphors could be fabricated through a simple low-temperature two-step chemical process, both the color and intensity of their emission can be tuned just by varying the molar concentration of the two dopant ions. The variation of the emission color and its intensity in the nanophosphors due to the dopant ion concentration has been explained considering the interband energy transfer from Mn 2+ ions to Co 2+ ions and creation of deep level defect states in the host nanocrystals. The synthesis process utilized in the present work opens up the possibility of fabricating low-cost, emission-tuned, rare-earth-free nanophosphors for developing high-efficiency light-emitting devices.

Monodisperse colloidal spheres with a high refractive index: their synthesis, assembly and application in structural colored materials

“…(1) Zinc sulfide (ZnS) spheres. ZnS is a widely applied metal sulfide with various important technological applications, such as pigment, [51][52][53] electroluminescence materials, 54,55 anode materials of batteries, 56 infrared windows [57][58][59] and solar cells. [60][61][62] The relatively high refractive index of its bulk material (B2.36 for cubic phase ZnS) and their transparency in the visible region make it an ideal candidate as building blocks for PCs.…”

Boron-Doped Exfoliated g-C3N4 Nanosheet-Based Phosphors for White Light-Emission and Photocatalytic Degradation

“…The exploration of the optical characteristics of nanostructured materials and their hybrids, especially group II−VI or III−V semiconductor materials, has been accelerated by the ongoing demand for effective, flexible display and light-emitting devices. 1,2 Due to their innovative optical and electrical properties, next-generation flexible optoelectronic devices made of two-dimensional (2D) nanomaterials like transitionmetal dichalcogenides and graphene have recently drawn a lot of interest. 3−5 Since g-C 3 N 4 , a 2D polymeric semiconductor resembling graphene and made of layered (tri-s-)triazine units, was initially investigated as an emerging metal-free visible-lightinduced photocatalyst for H 2 production, it has been extensively used in the photocatalysis and electrocatalysis fields.…”

Optical Dynamics of Copper-Doped Cadmium Sulfide (CdS) and Zinc Sulfide (ZnS) Quantum-Dots Core/Shell Nanocrystals

“…In type-I materials, the shell, having a larger bandgap than the core, provides a physical barrier to the charge carriers and helps in surface passivation and carrier confinement within the core. Typically, core/shell structures are composed of II-VI, IV-VI, and III-V group semiconductors with suitable combinations such as CdS/ZnS, CdSe/CdS, and InAs/CdSe [34]. Group II-VI semiconductor QDs are very attractive materials because of their wider range of optical, optoelectronic, and magnetic properties.…”