Gas phase enhancement of emission color quality in solid state LEDs
Light-emitting materials are made from a porous light-emitting semiconductor having quantum dots (QDs) disposed within the pores. According to some embodiments, the QDs have diameters that are essentially equal in size to the width of the pores. The QDs are formed in the pores by exposing the porous semiconductor to gaseous QD precursor compounds, which react within the pores to yield QDs. According to certain embodiments, the pore size limits the size of the QDs produced by the gas-phase reactions. The QDs absorb light emitted by the light-emitting semiconductor material and reemit light at a longer wavelength than the absorbed light, thereby “down-converting” light from the semiconductor material.
1. A composition comprising:
a light-emitting semiconductor material having pores therein, the pores comprising:
first pores having first pore diameters; and
second pores having second pore diameters larger than the diameters of the first pores;
first color-emitting quantum dots (QDs) disposed within the first pores and having diameters essentially equal to the first pore diameters; and
second color-emitting QDs disposed within the second pores and having diameters essentially equal to the second pore diameters; wherein
the composition is free of solvent.
2. The composition of claim 1 , wherein the pores are about 1 nm to about 20 nm in diameter.
3. The composition of claim 1 , wherein the light-emitting semiconductor material comprises as GaN, AlGaAs, AlGaInP, or AlGaInN, or any derivatives thereof.
4. The composition of claim 1 , wherein the QDs comprise a semiconductor material selected from CdS, CdSe, ZnS, ZnSe, InP, GaP, Cd 3 P 2 and In 2 Se 3 .
5. The composition of claim 1 , wherein at least one of the first and second color-emitting QDs emit green light when illuminated by light from the light-emitting semiconductor.
6. The composition of claim 1 , wherein at least one of the first and second color-emitting QDs emit red light when illuminated by light from the light-emitting semiconductor.
7. A light emitting device, comprising:
a light-emitting semiconductor material having pores therein, the pores comprising:
first pores having first pore diameters; and
second pores having second pore diameters larger than the diameters of the first pores;
first color-emitting quantum dots (QDs) disposed within the first pores and having diameters essentially equal to the first pore diameters; and
second color-emitting QDs disposed within the second pores and having diameters essentially equal to the second pore diameters; wherein
the light-emitting semiconductor material is free of solvent.
8. The device of claim 7 , wherein the pores are about 1 nm to about 20 nm in diameter.
9. The device of claim 7 , wherein the light-emitting semiconductor material comprises as GaN, AlGaAs, AlGaInP, or AlGaInN, or any derivatives thereof.
10. The device of claim 7 , wherein the QDs comprise a semiconductor material selected from CdS, CdSe, ZnS, ZnSe, InP, GaP, Cd 3 P 2 and In 2 Se 3 .
11. The device of claim 7 , wherein at least one of the first and second color-emitting QDs emit green light when illuminated by light from the light-emitting semiconductor.