Quantum dot material and method of curing
Print materials described herein include a first polymerization initiator comprising an initiator material having a thermal decomposition rate and a peak photo-initiated decomposition rate, wherein the thermal dissociation rate is higher than the peak photo-initiated decomposition rate; a vinylic monomer; a polyfunctional monomer; scattering particles; and quantum dots. Methods of making a quantum dot material using such print materials, and of incorporating into light emitting devices, are also described.
1. A print material, comprising:
a curable material;
scattering particles;
quantum dots;
a first polymerization initiator that is a photoinitiator; and
a second polymerization initiator that is a thermal initiator.
2. The print material of claim 1 , wherein the curable material includes at least one tetrafunctional cross-linker.
3. The print material of claim 1 , wherein the curable material comprises pentaerythritol tetraacrylate.
4. The print material of claim 1 , wherein the scattering particles are titanium dioxide particles.
5. The print material of claim 1 , wherein the curable material comprises one or more (meth)acrylates.
6. The print material of claim 1 , wherein
the scattering particles are 0.1-10 weight percent of a total weight of the print material; and
the quantum dots are 10-35 weight percent of the total weight.
7. The print material of claim 1 , further comprising a (poly)alkylene phosphate dispersant material.
8. The print material of claim 1 , wherein the first polymerization initiator is selected from the group consisting of AIBN, AICN, t-amyl peroxybenzoate, t-butyl peracetate, t-butyl peroxybenzoate, 2,2 bis(t-butylperoxy)butane, and 2,4 pentanedione peroxide.
9. The print material of claim 1 , wherein the curable material comprises a matrix monomer and a crosslinking agent.
10. A method of forming a quantum dot material, comprising:
depositing a print material onto a substrate, the print material comprising:
a first polymerization initiator that is a photoinitiator;
a second polymerization initiator that is a thermal initiator;
a vinylic monomer;
a polyfunctional monomer;
scattering particles; and
quantum dots; and
subsequently processing the deposited print material.
11. The method of claim 10 , wherein subsequently processing the deposited print material further comprises performing a thermal curing process on the substrate at a curing temperature of not less than 50° Celsius and not more than 100° Celsius.
12. The method of claim 11 , wherein the subsequent processing of the print material further comprises retaining at least 85% of an initial mass of the print material after the subsequent processing of the print material.
13. The method of claim 11 , wherein subsequently processing the deposited print material further comprises performing a photo-curing process using an ultra-violet (UV) light source.
14. The method of claim 13 , wherein performing the photo-curing process is performed prior to the thermal curing process.
15. The method of claim 14 , wherein the photo-curing process comprises exposing the print material to a UV radiation dose of at least 1.5 J/cm 2 and not more than 6 J/cm 2 over a duration of not more than 60 minutes.
16. The method of claim 10 , wherein the photoinitiator is an azo compound and the thermal initiator is a peroxide.
17. A display device comprising a cured film that is a polymerization product of a print material, the print material comprising:
a curable material;
scattering particles;
quantum dots;
a first polymerization initiator that is a photoinitiator; and
a second polymerization initiator that is a thermal initiator.
18. The display device of claim 17 , wherein the photoinitiator is an azo compound and the thermal initiator is a peroxide.
19. The display device of claim 18 , wherein the curable material comprises a matrix monomer and a crosslinking agent.
20. The display device of claim 19 , wherein the curable material comprises a neopentyl glycol di(meth)acrylate and a pentaerythritol tetraacrylate.