Light filter coating and method of production

Patent metadata

Field	Value
Publication number	US-2016258049-A1
Application number	US-201615057927-A
Country	US
Kind code	A1
Filing date	Mar 1, 2016
Priority date	Mar 2, 2015
Publication date	Sep 8, 2016
Grant date	—

Abstract

The present disclosure provides methods of applying a filtering coating to a substrate, comprising: depositing a solution on a surface of a substrate, wherein the solution comprises an organic solvent with nanorods dispersed within the solvent. Evaporation of the solution is allowed and/or controlled to increase a volume fraction of the nanorods in the solution as a function of the evaporation. Thus, an aligned deposit of the nanorods is provided as a function of the evaporation, wherein the aligned deposit of nanorods includes at least thousands of the nanorods with at least a majority of the nanorods aligned relative to a length of the nanorods.

First claim

Wat is claimed is:

1 . A method of applying a filtering coating to a substrate, comprising:
depositing a solution on a surface of a substrate, wherein the solution comprises an organic solvent with nanorods dispersed within the solvent, wherein the nanorods comprise cadmium selenide (CdSe) nanorods; allowing evaporation of the solution to increase a volume fraction of the nanorods in the solution as a function of the evaporation; and providing an aligned deposit of the nanorods, as a function of the evaporation, wherein the aligned deposit of nanorods comprises at least thousands of the nanorods with at least a majority of the nanorods aligned relative to a length of the nanorods.

2 . The method of claim 1 , wherein the nanorods comprise less than 4% by weight of the solution.

3 . The method of claim 1 , wherein the organic solvent comprises methylcyclohexane.

4 . The method of claim 3 , wherein the providing the aligned deposit of the nanorods comprises achieving alignment of the nanorods in less than 10 minutes from deposition of the solution on the surface per 0.10 ml of solution deposited on the substrate.

5 . The method of claim 4 , wherein the nanorods comprise nanorods having an average aspect ratio greater than 4, wherein an aspect ratio of each nanorod is defined by a length of the nanorod divided by a width of the nanorod.

6 . The method of claim 3 , wherein the allowing the evaporation comprises completing the evaporation within less than 30 minutes per 0.10 ml of solution deposited on the substrate.

7 . The method of claim 3 , wherein the nanorods comprise nanorods having an average length of less than 70 nm.

8 . The method of claim 3 , wherein the depositing the solution on the substrate comprises depositing a volume that is less than 0.50 ml onto a surface of the substrate.

9 . The method of claim 3 , wherein the evaporation of the solution induces depositing the aligned nanorods along a periphery of the deposited solution as a periphery of the solution recedes across the substrate during evaporation with the aligned nanorods aligning generally parallel with an exterior perimeter of the deposited solution.

10 . The method of claim 9 , wherein an alignment of the majority of the nanorods comprises a gradient of alignment with an increased alignment of the nanorods approaching a central area of the aligned deposit of the nanorods.

11 . The method of claim 3 , further comprising:
tuning an optical filtering effect resulting from the aligned deposit of the nanorods comprising:
identifying lyotropic aspects corresponding to one or more types of potential nanorods;
establishing a predicted alignment of each of the one or more types of potential nanorods as a function of the lyotropic aspects of the one or more types of potential nanorods; and
selecting, based on the predicted alignment, one or more of the potential nanorods.

12 . The method of claim 11 , wherein the establishing a predicted alignment comprises estimating an isotropic-nematic phase coexistence based on a small angle x-ray scatting characterization of aligned nanorods.

13 . The method of claim 3 , further comprising:
cleaning a first stock of the nanorods comprising: repeating a series of dispersions of the first stock in hexane and centrifuging producing cleaned nanorods; preparing, following the cleaning of the first stock, the cleaned nanorods to obtain prepared clean nanorods by repeating multiple times a series of: dispersing the cleaned nanorods in the methylcyclohexane producing a preliminary solution, centrifuging the preliminary solution and transferring the supernatant of the preliminary solution following the centrifuging; and dispersing a first weighted quantity of the prepared clean nanorods in a first predefined volume of the organic solvent producing the solution comprising the organic solvent and the nanorods at less than 4% by weight.

14 . The method of claim 1 , wherein the depositing the solution on the substrate comprises depositing the solution in a first reservoir formed at a first end of one or more microchannels each having a width of less than 200 μm, wherein an average length of the nanorods is greater than 25 nm with an aspect ratio of greater than 10; and
wherein the providing the aligned deposit of the nanorods comprises providing the alignment with the lengths of a majority of the nanorods being aligned substantially parallel with a length of the one or more microchannels.

15 . The method of claim 1 , wherein the depositing the solution on the substrate comprises depositing the solution in a reservoir formed at a first end of one or more microchannels each having a width of less than 200 μm, wherein an average length of the nanorods is less than 25 nm with an aspect ratio of less than 10; and
wherein the providing the aligned deposit of the nanorods comprises providing the alignment with the lengths of a majority of the nanorods being aligned substantially perpendicular with a length of the one or more microchannels.

16 . The method of claim 1 , wherein the allowing the evaporation comprises inducing evaporation by maintaining an airflow over the surface.

17 . The method of claim 16 , wherein the maintaining the airflow over the surface comprises maintaining an airflow of between 80 and 100 feet per minute (fpm).

18 . A method of applying an optical filtering coating to a substrate, comprising:
depositing a solution on a surface of a substrate, wherein the solution comprises an organic solvent with nanorods dispersed within the solvent; allowing evaporation of the solution to increase a volume fraction of the nanorods in the solution as a function of the evaporation; achieving alignment of the nanorods in less than 10 minutes from deposition of the solution on the surface per 0.10 ml of solution deposited on the substrate; and providing an aligned deposit of the nanorods, as a function of the evaporation, wherein the aligned deposit of nanorods comprises at least thousands of the nanorods with at least a majority of the nanorods aligned relative to a length of the nanorods.

19 . The method of claim 18 , wherein the nanorods comprise less than 4% by weight of the solution.

20 . The method of claim 18 , wherein the nanorods comprise nanorods having an average aspect ratio greater than 4, wherein an aspect ratio of each nanorod is defined by a length of the nanorods divided by a width of the nanorod.

21 . The method of claim 18 , wherein the organic solvent comprises methylcyclohexane.

22 . The method of claim 21 , wherein the nanorods comprise cadmium selenide (CdSe) nanorods.

23 . The method of claim 21 , further comprising:
cleaning a first stock of the nanorods comprising: repeating a series of dispersions of the first stock in hexane and centrifuging producing cleaned nanorods; preparing, following the cleaning of the first stock, the cleaned nanorods to obtain prepared clean nanorods by repeating multiple times a series of: dispersing the cleaned nanorods in the methylcyclohexane producing a preliminary solution, centrifuging the preliminary solution and transferring the supernatant of the preliminary solution following the centrifuging; and dispersing a first weighted quantity of the prepared clean nanorods in a first predefined volume of the organic solvent producing the solution comprising the organic solvent and the nanorods at less than the 4% by weight.

24 . T

Assignees

• Stancil Kimani A
• Hammonds James S
• Univ Howard

Inventors

• Stancil Kimani A
• Hammonds James S

Classifications

• C23C24/08 Primary

  by application of heat or pressure and heat (C23C24/04 takes precedence) · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• G02B1/002

  made of materials engineered to provide properties not available in nature, e.g. metamaterials · CPC title

• C23C14/0021 Primary

  Reactive sputtering or evaporation · CPC title