White LED Based on YAG : Ce,Gd Phosphor and CdSe–ZnS Core/Shell Quantum Dots

Abstract

Core/shell CdSe-ZnS quantum dots (QDs) with a peak emission wavelength of 618 nm and size of 5.5 nm were synthesized by thermal deposition approach. High photoluminescence efficiency with a quantum yield of more than 48% has been achieved. Red-shift of a peak emission wavelength from 532 to 568 nm was realized by doping Gd 3+ ions into the YAG : Ce 3+ to substitute some Y 3+ ions. To compensate the poor color rendering index (CRI) of the YAG : Ce-based white light-emitting diode (LED) due to the lack of red spectral component, CdSe-ZnS QDs were blended into YAG : Ce 3+ , Gd 3+ phosphors. Prominent spectral evolution has been achieved by increasing the content of QDs. White LED combining a blue LED with the blends of phosphor and QDs with a weight ratio of 1 : 1, has been demonstrated with an improved CRI value of 90.Index Terms-CdSe-ZnS quantum dots (QDs), white light-emitting diode (LED), YAG : Ce 3+ , Gd 3+ .

Broadband and omnidirectional light harvesting enhancement of fluorescent SiC

“…White light-emitting diodes (LEDs) consisting of a nitride-based blue LED chip and phosphor are very promising candidates for the general lighting applications as energy-saving and environment friendly light sources [1][2][3][4][5]. Recently, donor-acceptor doped fluorescent SiC has been proven as a highly efficient wavelength converter material much superior to the phosphors in terms of high color rendering index (CRI) value and long lifetime [6,7].…”

Omnidirectional luminescence enhancement of fluorescent SiC via pseudoperiodic antireflective subwavelength structures

“…High-efficiency nitride-based LEDs are extensively reported [1][2][3] and phosphors are the most common wavelength converters with high conversion efficiency [4][5][6][7]. Recently, donor-acceptor doped fluorescent SiC has been proven as a highly efficient wavelength converter material much superior to the phosphors in terms of high color rendering index (CRI) value and long lifetime [8,9].…”

The Influence of the Thermal Effect on CdSe/ZnS Quantum Dots in Light-Emitting Diodes

“…The CdSe/ZnS QDs were synthesized using the hot-injection method [28], [29]. Cadmium acetate was dissolved into trioctylphoshine oxide and hexadecylamine solvent at 300 C. The Se precursor was dissolved in trioctylphosphine.…”