Luminescence of Er Doped ZnS Quantum Dots Excited by Infrared Lasers

Abstract

ZnS:Er quantum dots were prepared in aqueous medium from readily available precursors. The construction, morphology and luminescence properties of the ZnS:Er quantum dots were evaluated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectra. The average particle size was calculated using the Scherrer formula to be 4 nm, which is also observed from high resolution transmission electron microscopy (HRTEM) image. Different laser wavelengths at 976 +/- 2 nm and 1480 nm were utilized as the excitation source. ZnS:Er quantum dots had a fluorescence spectrum in 1550 nm region through the 4I13/2 --> 4I15/2 transition. Furthermore, intensity increased with increasing excitation intensity and dopant concentration. The reason for the photoluminescence spectra broadening is discussed. It is because the energy levels of Er3+ are split by a coulombic interaction between electrons, including spin correction and spin-orbit coupling, and eventually by the Stark effect due to ZnS QDs crystal field and local coordination.

Correlated Color Temperature Tunable White Electroluminescence from Cadmium-Free ZnS Quantum Dots

“…As a blue-light-emitting semiconductor, nanoscale ZnS prepared via convenient routes displays remarkable optical properties. [19][20][21] Photoluminescence (PL) spectra with various colors from defects of ZnS QDs were observed 19 22 23 and the PL quantum yield has reached as high as 31%. 19 So combined defects emission of ZnS QDs becomes a prospective method to accomplish white EL.…”

Vertically aligned single-crystal zinc sulfide nanotubes with hexagonal cross-sections and optical properties

“…As an important II-VI semiconductor with a wide bandgap of 3.8 eV, ZnS has received much attention due to their unique optical, electrical, and optoelectronic properties [5,6] and potential applications in many aspects, such as sensors [7], lasers [8], photocatalyses [9], and light-emitting diodes [10]. Over the past decade, a considerable effort has been made to prepare and investigate ZnS tubular structures by various template routes [11][12][13][14][15][16][17][18].…”

Efficient Infrared Luminescence of Er<SUB>2</SUB>S<SUB>3</SUB>/ZnS Core/Shell Quantum Dots and IR QDs-LED

“…Among these types, the doped semiconductor quantum dots can achieve light emissions with a broader spectrum by tuning the doping ion. The doped semiconductor quantum dots have been numerously investigated [14][15][16] because of their excellent performance. For instance, transition metal ions such as Mn 2+ , Cu 2+ , Co 2+ or rare earth ions such as Eu 3+ , Er 3+ , Tb 3+ were doped into II-VI semiconductor matrix like CdSe, CdS, ZnS, ZnSe, etc.…”