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 method of forming a quantum dot material, comprising:
depositing a print material onto a substrate, the print material comprising:
a first polymerization initiator comprising a first initiator material having a first decomposition rate during a thermal initiation process and a second decomposition rate during a photo-initiation process, wherein the first decomposition rate is higher than the second decomposition rate;
a second polymerization initiator comprising a second initiator material having a third decomposition rate during the thermal initiation process and a fourth decomposition rate during the photo-initiation process, wherein the third decomposition rate is less than the fourth decomposition rate;
a vinylic monomer;
a polyfunctional monomer;
scattering particles; and
quantum dots; and
subsequently processing the deposited print material.
2. The method of claim 1 , 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.
3. The method of claim 2 , wherein a temperature of the thermal curing process is not less than 650 and not more than 850 Celsius.
4. The method of claim 2 , 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.
5. The method of claim 2 , wherein subsequently processing the deposited print material further comprises performing a photo-curing process using an ultra-violet (UV) light source.
6. The method of claim 5 , wherein performing the photo-curing process is performed prior to the thermal curing process.
7. The method of claim 6 , 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.
8. The method of claim 5 , wherein performing the photo-curing process comprises exposing the print material to UV light having a wavelength of at least 200 nm to not more than 410 nm.
9. A method of making a quantum dot material, comprising:
applying a print material to a top surface of a substrate, the print material comprising:
a vinylic monomer;
a polyfunctional monomer;
reflective particles;
quantum dots; and
a mixture of a first polymerization initiator and a second polymerization initiator, wherein
the first polymerization initiator comprises a first initiator material having a first thermal decomposition rate and a first photo-initiated decomposition rate, the first thermal decomposition rate being greater than the first photo-initiated decomposition rate, and wherein
the second polymerization initiator comprises a second initiator material having a second thermal decomposition rate and a second photo-initiated decomposition rate, the second thermal decomposition rate being less than the second photo-initiated decomposition rate; and
processing the applied print material on the top surface of the substrate.
10. The method of claim 9 , wherein processing the applied print material on the top surface of the substrate comprises heating the print material and the substrate to a curing temperature of not less than 50° Celsius and not more than 100° Celsius.
11. The method of claim 10 , wherein processing the applied print material on the top surface of the substrate further comprises heating the print material and the substrate to a curing temperature of not less than 65° Celsius and not more than 85° Celsius.
12. The method of claim 9 , wherein processing the applied print material on the top surface of the substrate comprises retaining not less than 85% of an initial mass of the applied print material after heating the print material and the substrate to the curing temperature.
13. The method of claim 9 , wherein processing the applied print material on the top surface of the substrate comprises performing a photo-initiated curing process using an ultra-violet (UV) light source.
14. The method of claim 13 , wherein processing the applied print material on the top surface of the substrate further comprises heating the print material to a curing temperature.
15. The method of claim 13 , wherein the photo-initiated curing process comprises exposing the applied print material to a cumulative UV radiation flux 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 13 , wherein performing the photo-initiated curing process further comprises exposing the applied print material to UV light having a wavelength of not less than 200 nanometers (nm) and not more than 410 nm.
17. The method of claim 14 , wherein the performing a photo-initiated curing process and the heating the print material to a curing temperature are performed at least partly concurrently.
18. A method of making a quantum dot material, comprising:
printing a print material on a substrate surface, the print material comprising:
a vinylic monomer;
a polyfunctional monomer;
white particles;
wavelength-shifting particles; and
a polymerization initiator mixture, comprising
a first polymerization material having a first thermal decomposition rate and a first photo-initiated decomposition rate, wherein the first thermal decomposition rate is greater than the first photo-initiated decomposition rate, and
a second polymerization material having a second thermal decomposition rate and a second photo-initiated decomposition rate, wherein the second thermal decomposition rate is less than the second photo-initiated decomposition rate; and
curing the print material on the substrate surface.
19. The method of claim 18 , wherein curing the print material on the substrate surface comprises performing a uni-directional photo-initiated curing process.
20. The method of claim 18 , wherein curing the print material on the substrate surface comprises performing a bi-directional photo-initiated curing process.
21. The method of claim 18 , wherein curing the print material on the substrate comprises performing a thermal curing process.
22. The method of claim 21 , wherein curing the print material on the substrate further comprises heating the print material to a curing temperature.