Phosphor (Energy Converter)
Inorganic phosphor materials
“Classical” inorganic phosphors usually consist of a host lattice with activator ions doped into it in small concentrations, typically a few mole percent or less.
Host lattice & Activator ion
1st type : weak interaction (Ln3+)
2nd type: strong interaction ( Mn2+, Eu2+, Ce3+, Pb2+,Sb3+, Ce3+, MoO42-, NbO43-)
Activator (+ Sensit
What is LED?
Light Emission Diode
Using P-N Junction
Wave length is defined
by Element’s Band Gap
Compound Red, Green, Blue
↓
Express Color!(white…)
Core : 2~10 nm
- Ⅱ-Ⅳ element (CdSe, CdTe, Cds)
Shell
- metallic molecular plating(ZnS, ZnSe)
Polymer Coating
- To disperse in the aqueous solution
5.2 Drug Delivery System
5.2.1 Advantage of Nano-drug delivery system
By diagnosis, and for treatment, we need enhanced drug delivery system. Drug delivery system of these days is just eat and let it flow through the body. It is not good at efficiency. Because the digestive system sometimes digest and remove the drug before it reaches to the target.
For enhancing the efficiency of drug
②White emission using mixtures of CdSe quantum dots and PMMA as a phosphor
This paper explain WLED that have mixture stucture (one single chip(emit blue light) and cdse/PMMA quantum dots). CdSe quantum dots are synthesized by the wet chemical method using CdO and Se powder as precursor. And they control the size of quantum dot and mix the phospors(PMMA).
These quantum dots have three differe
Free(wannier-mott)
Radius >> a(exciton Bohr radius)
Small binding energy :~ 0.01 eV
Delocalized states
Move freely through crystal
(semiconductors)
Tighthly-bound(Frenkel)
Radius ~ a(exciton Bohr radius)
large binding energy : 0.1 -1.0 eV
localized on one lattice site
Moving by hopping
(insulators and molecules)
Eadd = △E + Ec
Ec = e2/C
C = 2πεεod
(depend on geometr