WO2020072703A2

WO2020072703A2 - Photoresponsive chalcogenide hybrid organic/inorganic polymer films

Info

Publication number: WO2020072703A2
Application number: PCT/US2019/054368
Authority: WO
Inventors: Dong-Chul Pyun; Robert A. Norwood; Abhinav NISHANT; Laura Anderson; Tristan S. KLEINE; Nicholas P. Lyons
Original assignee: University of Arizona
Current assignee: University of Arizona
Priority date: 2018-10-02
Filing date: 2019-10-02
Publication date: 2020-04-09
Anticipated expiration: 2021-04-02
Also published as: US20210389504A1; WO2020072503A1; WO2020072703A3; US12298472B2

Abstract

The present invention provides certain CHIP films and coatings, as well as the preparation and uses thereof.

Description

PHOTORESPONSIVE CHALCOGENIDE HYBRID ORGANIC/INORGANIC

POLYMER FILMS

By

Dong-Chul Pyun,

Robert A. Norwood,

Abhinav Nishant,

Laura E. Anderson,

Tristan S. Kleine, and

Nicholas P. Lyons

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Appl. No. 62/740,372, filed October 2, 2018. The content of the foregoing application is relied upon and is incorporated by reference herein in its entirety. FIELD OF THE INVENTION

[0002] The present invention is directed to polymeric materials, the use thereof, and the preparation thereof.

GOVERNMENT SUPPORT

[0003] This invention was made with government support under Grant No. 1607971 awarded by National Science Foundation (NSF). The government has certain rights in the invention.

BACKGROUND

[0004] Integrated photonics is poised to dominate the photonics industry thanks to a mature CMOS integrated circuit (IC) manufacturing platform, namely, silicon photonics. Despite growing on-chip functionality and integration density, efficient, low cost, scalable and high throughput optical interfacing of photonic ICs (PICs) has remained a challenge. While optical fibers have dominated this area, they also have become a bottleneck due to their low coupling efficiency, lack of scalability, and extremely low misalignment tolerance. So, while chip manufacturing costs constantly decrease, the use of high-precision packaging tools and the subsequent reduction in throughput impose significant additional costs. Therefore, lack of an economical optical packaging solution for chip-to-chip and chip-to-board connectivity remains a barrier to widespread deployment of silicon photonics, which can address applications such as telecommunications and burgeoning data center photonics, as well as Internet of Things (loT) sensors, with sensors for health, manufacturing, and autonomous vehicles critical for full realization of modern community concepts such as smart cities.

[0005] One aspect of the invention encompasses methods for making optical waveguides with high refractive index (n, or Rl), broadband infrared transparent chalcogenide hybrid inorganic/organic polymers (CHIPs), which address both conventional optical communications applications at wavelengths such as 1550nm and 1310nm wavelength and emerging applications in the mid-wave infrared (MWIR) from 3 microns to 5 microns wavelength. Very few materials choices exist for integrated photonics in the MWIR region of the optical spectrum, and no low- cost polymer system is currently viable. In some cases the CHIPs waveguides may be used as optical interconnects in conjunction with optical fibers and silicon PICs, acting to efficiently deliver light from the optical fiber to the silicon PIC and vice versa. In the MWIR, significant opportunities exist for stand-alone devices such as integrated, compact and portable MWIR spectrometers, which could be used for applications such as human breath analysis, toxic substance detection and carbon dioxide monitoring among many others, since the MWIR region has signature IR vibrations for many molecules.

[0006] A key feature of the waveguides of the invention is that the CHIPs materials have higher refractive indices than other known polymers. This allows creation of very compact waveguide structures such as arrayed waveguide gratings, microring resonators, and small radius of curvature waveguide bends.

[0007] Another key feature of the waveguides of the invention is that CHIPs materials are transparent at mid-infrared wavelength between 3.5 and 5.5 microns, and there a very few materials (notably germanium, chalcogenide glass and zinc selenide), that are transparent in this region.

DESCRIPTION

Definitions

[0008] As used herein, sulfur can be provided as elemental sulfur, for example, in powdered form. Under ambient conditions, elemental sulfur primarily exists in an eight-membered ring form (Ss) which melts at temperatures in the range of 120°C -130 °C and undergoes an equilibrium ring-opening polymerization (ROP) of the Ss monomer into a linear polysulfane with diradical chain ends. As the person of skill in the art will appreciate, while Ss is generally the most stable, most accessible and cheapest feedstock, many other allotropes of sulfur can be used (such as other cyclic allotropes, derivable by melt-thermal processing of Ss). Any sulfur species that yield diradical or anionic polymerizing species when heated as described herein can be used in practicing the present invention. [0009] The term “CHIP” is used herein to refer to a chalcogenide hybrid inorganic/organic polymer.

[0010] The term“CHIP” is used herein interchangeably with“chalcogenide hybrid inorganic/organic polymer.”

[001 1] As used herein, the term“chalcogenide” refers to a compound containing one or more chalcogen elements. One of ordinary skill in the art will understand that the classical chalcogen elements are sulfur, selenium and tellurium. In accordance with the present invention, the use of chalcogenide also refers to compounds and/or polymers containing selenium.

[0012] As known to one of ordinary skill in the art, the term “isomer” refers to compounds having the same formula but differ in arrangement. For instance, isomers of cyclic selenium sulfides, such as Se₂S₆ and SesSs, can have different placements of the Se units in the ring (e.g., S-Se-Se-S or S-Se-S). Isomers of Se₂S₆ include 1 ,2-isomers, 1 ,3-isomers, 1 ,4-isomers, and 1 ,5-isomers, wherein the numbers refer to the position of the Se units in the eight-membered ring. [0013] As known to one of ordinary skill in the art, the term“visible” refers to a portion of the electromagnetic spectrum that falls in the range of 390 to 700 nm. As used herein, the term“infrared” (IR) refers to a portion of the electromagnetic spectrum that falls in the range of 700 nm to 1 mm. Subsets of the IR spectrum include near- IR (700 nm to 3mΐti), mid-IR (3-8 mΐti), long-wavelength IR (8-15 mΐti) and far-IR (15mΐti to 1 mm). [0014] As used herein, the terms“those defined above” and“those defined herein” when referring to a variable incorporates by reference the broad definition of the variable as well as any narrow and/or preferred, more preferred and most preferred definitions, if any. [0015] As used herein, the term“about” refers to plus or minus 10% of the referenced number.

[0016] As used herein, the term“infrared” (IR) refers to a portion of the electromagnetic spectrum that falls in the range of 700 nm to 1 mm. Subsets of the IR spectrum include near-IR (700 and 1 ,100 nanometers), shortwave IR (SWIR) (1 ,100 and 3,000 nanometers), mid-IR (3-8 mΐti), long-wavelength IR (8-15 mΐti) and far-IR

(15mΐti to 1 mm).

[0017]“A smart device” is an electronic device, generally connected to other devices or networks via different wireless protocols such as Bluetooth, NFC, Wi-Fi, LiFi, 3G, 4G, 5G, etc., that can operate to some extent interactively and autonomously. Several notable types of smart devices are smartphones, phablets and tablets, smartwatches, smart bands, smart key chains and smart speakers. The term can also refer to a device that exhibits some properties of ubiquitous computing, including artificial intelligence (Al).

[0018] The term“substrate” as herein refers to a surface on which a film of the invention can adhere. For example, glass, a high refractive index infrared optical material (such as germanium, silicon, or zinc selenide). It includes transmissive materials, generally.

[0019] The term“CHIP polymer(ic) material” is used interchangeably with the term “CHIP(s) material” as used herein refers generally to organic/inorganic polymeric materials comprised of chalcogen units (e.g., S, Se) and organic comonomers.

[0020] CHIP materials encompassed by the present invention may range in the composition from 10-90 wt% sulfur, with unsaturated organic, inorganic, or hybrid comonomers (e.g., styrenic comonomer, amine monomer, thiol monomer, alkynylly unsaturated monomer, nitrone monomer, aldehyde monomer, ketone monomer, epoxide monomer, thiirane monomer, ethylenically unsaturated monomer, etc.) ranging from 90-10 wt%. Without wishing to limit the invention to a particular theory, the CHIPs material may be comprised of chalcogenide covalent bonds in the polymer (e.g., S-S bonds) that are dynamic covalent bonds and stimuli- responsive to heat, mechanical stress, or light that enables crosslinking of a thin film.

[0021] In some embodiments, a high refractive index CHIP material (where n is greater than 1.5, preferably n is about 1.5 to about 2.5, more preferably n is about 1.7 to about 2.2) with varying content of selenium atoms and sulfur-selenium bonds in the polymer (10-75 wt% Se) with unsaturated organic, inorganic, or hybrid comonomers ranging from 90-10 wt%, where the S-S, or Se-S bonds are also stimuli-responsive and able to form crosslinked films by exposure to heat, mechanical stress or light may be used in the invention.

[0022] As used herein, a“styrenic comonomer” is a monomer that has a vinyl functional group. The styrenic comonomer may comprise a styrene and at least one reactive functional group. As known to one of ordinary skill in the art, a styrene is a derivative of benzene ring that has a vinylic moiety. The sulfur diradicals can link to the vinylic moieties of the styrenic commoners to form the sulfur-styrenic polymer. In certain embodiments, the reactive functional group may be a halogen, an alkyl halide, an alkyl, an alkoxy, an amine, or a nitro functional group. Non-limiting examples of styrenic comonomers include bromostyrene, chlorostyrene, fluorostyrene, (trifluoromethyl)styrene, vinylaniline, acetoxystyrene, methoxystyrene, ethoxystyrene, methylstyrene, nitrostyrene, vinylbenzoic acid, vinylanisole, and vinylbenzyl chloride.

[0023] As used herein, the term“amine monomer” is a monomer that has an amine functional group. In one embodiment, aromatic amines and multi- functional amines may be used. Amine monomers include, but are not limited to, aromatic amines, m-phenylenediamine, and p-phenylenediamine. The various types of phenylenediamines are inexpensive reagents due to their wide-spread use in the preparation of many conventional polymers, e.g., polyureas, polyamides

[0024] As used herein, the term“thiol monomer” is a monomer that has a thiol functional group. Thiol monomers include, but are not limited to, 4,4'- thiobisbenzenethiol and the like. The term“sulfide monomers” are monomers that have sulfide functional groups.

[0025] As used herein, an alkynylly unsaturated monomer is a monomer that has an alkynylly unsaturated functional group (i.e. triple bond). The term

“alkynylly unsaturated monomer” does not include compounds in which the alkynyl unsaturation is part of a long chain alkyl moiety (e.g., unsaturated fatty acids, or carboxylic salts, or esters such as oleates, and unsaturated plant oils). In one embodiment, aromatic alkynes, both internal and terminal alkynes, multi- functional alkynes may be used. Examples of alkynylly unsaturated monomers include, but are not limited to, ethynylbenzene, 1-phenylpropyne, 1 ,2- diphenylethyne, 1 ,4-diethynylbenzene, 1 ,4-bis(phenylethynyl) benzene, and 1 ,4-diphenylbuta-1 ,3-diyne.

[0026] As used herein, the term“nitrone monomer” is a monomer that has a nitrone groups. In one embodiment, nitrones, dinitrones, and multi-nitrones may be used. Examples include, but are not limited to, N-benzylidene-2- methylpropan-2-amine oxide.

[0027] As used herein, the term“aldehyde monomer” is a monomer that has an aldehyde functional group. In one embodiment, aldehydes, dialdehydes, and multi- aldehydes may be used.

[0028] As used herein, the term“ketone monomer” is a monomer that has a ketone functional group. In one embodiment, ketones, di-ketones, and multi- ketones may be used.

[0029] As used herein, the term“epoxide monomer” is a monomer that has epoxide functional groups. Non-limiting examples of such monomers include, generally, mono- or polyoxiranylbenzenes, mono- or polyglycidylbenzenes, mono- or polyglycidyloxybenzenes, mono- or polyoxiranyl(hetero)aromatic compounds, mono-or polyglycidyl(hetero)aromatic compounds, mono- or polyglycidyloxy(hetero)aromatic compounds, diglycidyl bisphenol A ethers, mono- or polyglycidyl(cyclo)alkyl ethers, mono- or polyepoxy(cyclo)alkane compounds and oxirane-terminated oligomers. In one preferred embodiment, the epoxide monomers may be benzyl glycidyl ether and tris(4- hydroxyphenyl)methane triglycidyl ether. In certain embodiments, the epoxide monomers may include a (hetero)aromatic moiety such as, for example, a phenyl, a pyridine, a triazine, a pyrene, a naphthalene, or a polycyclic (hetero)aromatic ring system, bearing one or more epoxide groups. For example, in certain embodiments, the one or more epoxide monomers are selected from epoxy(hetero)aromatic compounds, such as styrene oxide and stilbene oxide and (hetero)aromatic glycidyl compounds, such as glycidyl phenyl ethers (e.g., resorcinol diglycidyl ether, glycidyl 2-methylphenyl ether), glycidylbenzenes (e.g., (2,3-epoxypropyl)benzene) and glycidyl heteroaromatic compounds (e.g., N-(2,3-epoxypropyl)phthalimide). In certain desirable embodiments, an epoxide monomer will have a boiling point greater than 180 °C, greater than 200 °C, or even greater than 230 °C at the pressure at which polymerization is performed (e.g., at standard pressure, or at other pressures).

[0030] As used herein, the term“thiirane monomer” is a monomer that has a thirane functional group. Non-limiting examples of thiirane monomers include, generally, mono- or polythiiranylbenzenes, mono- or polythiiranylmethylbenzenes, mono- or polythiiranyl(hetero)aromatic compounds, mono- or polythiiranylmethyl(hetero)-aromatic compounds, dithiiranylmethyl bisphenol A ethers, mono- or polydithiiranyl (cyclo)alkyl ethers, mono- or polyepisulfide(cyclo)alkane compounds, and thiirane- terminated oligomers. In some embodiments, thiirane monomers may include a (hetero)aromatic moiety such as, for example, a phenyl, a pyridine, a triazine, a pyrene, a naphthalene, or a poly cyclic (hetero)aromatic ring system, bearing one or more thiirane groups. In certain desirable embodiments, a thiirane monomer can have a boiling point greater than 180 °C, greater than 200 °C, or even greater than 230 °C at the pressure at which polymerization is performed (e.g., at standard pressure).

[0031] As used herein, an ethylenically unsaturated monomer is a monomer that contains an ethylenically unsaturated functional group (i.e. double bond). The term “ethylenically unsaturated monomer” does not include cyclopentadienyl species such as cyclopentadiene and dicyclopentadiene. The term “ethylenically unsaturated monomer” does not include compounds in which the ethylenic unsaturation is part of a long chain alkyl moiety (e.g. unsaturated fatty acids such as oleates, and unsaturated plant oils).

[0032] Non-limiting examples of ethylenically unsaturated monomers include vinyl monomers, acryl monomers, (meth)acryl monomers, unsaturated hydrocarbon monomers, and ethylenically-terminated oligomers. Examples of such monomers include, generally, mono- or polyvinylbenzenes, mono- or polyisopropenylbenzenes, mono- or polyvinyl(hetero)aromatic compounds, mono- or polyisopropenyl(hetero)-aromatic compounds, acrylates, methacrylates, alkylene di(meth)acrylates, bisphenol A di(meth)acrylates, benzyl (meth)acrylates, phenyl(meth)acrylates, heteroaryl (meth)acrylates, terpenes (e.g., squalene) and carotene. In other embodiments, the ethylenically unsaturated monomers may include a (hetero)aromatic moiety such as, for example, phenyl, pyridine, triazine, pyrene, naphthalene, or a polycyclic (hetero)aromatic ring system, bearing one or more vinylic, acrylic or methacrylic substituents. Examples of such monomers include benzyl (meth)acrylates, phenyl (meth)acrylates, divinylbenzenes (e.g., 1 ,3- divinylbenzene, 1 ,4-divinylbenzene), isopropenylbenzene, styrenics (e.g., styrene, 4-methylstyrene, 4-chlorostyrene, 2,6-dichlorostyrene, 4-vinylbenzyl chloride), diisopropenylbenzenes (e.g., 1 ,3-diisopropenylbenzene), vinylpyridines (e.g., 2-vinylpyridine, 4-vinylpyridine), 2,4,6-tris((4- vinylbenzyl)thio)-1 ,3,5-triazine and divinylpyridines (e.g., 2,5-divinylpyridine). In certain embodiments, the ethylenically unsaturated monomers (e.g., including an aromatic moiety) bear an amino (i.e., primary or secondary) group, a phosphine group or a thiol group. One example of such a monomer is vinyldiphenylphosphine.

[0033] As used herein, the term“photoresponsive medium” refers to a material that is able to respond to light irradiation by undergoing changes in at least its refractive index or solubility in organic solvent. In some embodiments, the change to the refractive index and/or solubility is irreversible. Examples organic solvents include alcohols, such as methanol, ethanol; aldehydes such as acetone; aromatics solvents, such as benzene, toluene; chlorobenzene, dicholorobenzene; nonpolar aprotic solvents, such as, tetrahydrofuran, or dichloromethane; and other organic solvents known in the art.

[0034] As used herein, the term high-refractive-index polymer (HRIP) is a polymer that has a refractive index greater than 1.5.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The features and advantages of the present invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings in which:

[0037] FIG. 1 shows UV induced refractive index change

[0038] FIG. 2 shows UV induced refractive index change

[0039] FIG. 3 shows UV induced refractive index change

[0040] FIG. 4 shows UV Visible Spectroscopy

[0041] FIG. 5 shows fabrication of an exemplary waveguide (WG)

[0042] FIG. 6 shows microscope images of photobleached waveguides (WG)

[0043] FIG. 7 shows optical characterization of waveguide

[0044] FIG. 8 shows optical characterization of waveguide

[0045] FIG. 9 shows profilometry of photobleached WG surface. The photodefined waveguide showed ~100nm peak using a Dektak® stylus profiler, which would indicate that the exposed region of S-DIB film is being gradually removed by the chemistry caused by the UV radiation. The Dektak is a type of surface profilometer, that measures the thickness of a film

[0046] FIG. 10 shows waveguide characterization

[0047] FIG. 11 shows waveguide characterization

[0048] FIG. 12 shows waveguide characterization [0049] FIG. 13 shows photocured waveguide geometry

[0050] One aspect of the invention pertains to a method comprising using high refractive index polymers based on CHIPs as a photoresponsive medium. [0051] In some embodiments the invention encompasses a method comprising directly photopatterning unstructured polymer thin films of CHIPs based on poly(sulfur-random-(1 ,3-diisopropenylbenzene) (abbreviated to poly(S-r-DIB) by exposure with ultraviolet radiation with any development, or solvent washing steps. By irradiation through various photomasks available through standard photography methods, arbitrary patterns may be directly photopatterned into thin films. Inventors also surprisingly discovered that a reduction in the refractive index in photoexposed regions on the order of 10^L -2 refractive index units), which enables direct fabrication of optical waveguide architectures and devices. [0052] Another aspect of the invention is directed to a photoresponsive medium comprising one or more CHIPs. Without wishing to limit the invention to a particular theory, the CHIPs photoresponsive medium has the property of changing its refractive index upon the application of certain wavelengths of radiation, preferably in the ultraviolet between 350-400nm, with the amount of refractive index change proportional to the duration of the illumination.

[0053] As used herein, the“medium” may include potential polymer claddings such as polymethylmethacrylate, polycarbonate, polystyrene, cellulose acetate, and polydimehtylsiloxane, ZPU (ChemOptics), polyimide, polyester, optical epoxy, acrylate copolymers. Furthermore, “medium” may include substrates that can act as claddings such as borosilicate glass, fused silica, silicon dioxide on silicon, and sapphire.

[0054] In some embodiments, the invention encompasses a method of preparing a photopatterned, unstructured polymer thin film, said method comprising photopatterning unstructured polymer thin films of one or more CHIPs based on poly(sulfur-random-(1 ,3-diisopropenylbenzene) (poly(S-r DIB) by exposure with ultraviolet radiation without any development, or solvent washing steps to obtain a refractive index contrast in the polymer.

[0055] This is the first discovery of photopatterning with CHIPs materials and is a useful technological advance for optical photonics using inexpensive, solution processable CHIPs materials.

[0056] In some embodiments, the invention encompasses an interactive label that can be scanned by a smart device (such as a smart phone) comprising a photoresponsive medium of the invention.

[0057] In further embodiments, the invention encompasses a film comprising a photoresponsive medium of the invention. In some embodiments, this film may be used in an interactive label. [0058] In some embodiments, the invention encompasses a multilayer device

comprising at least one layer of chalcogenide-based polymer (e.g. a CHIP material), wherein said device comprises:

(A) at least a portion of the area of the layer which has been photoexposed by a method comprising using a mask or a maskless lithography system to create a photopattern, which comprises an unexposed region and an photoexposed region, thereby fabricating at least one layer of said polymer so as to create an optical waveguide, wherein said photoexposed region results in crosslinking of the polymer (or CHIP material), rendering said photoexposed region insoluble in solvents that can rinse away the uncured material (or polymer), resulting in a physically defined waveguide core; and

(B) An optical waveguide made using said method (A).

[0059] In some embodiments, the invention encompasses a multilayer device

including a layer of chalcogenide-based polymer, e.g. a CHIPs material, wherein said device comprises:

(A) at least a portion of the area of the layer which has been photoexposed by a method comprising a. using mask or with a maskless lithography system to create a photopattern;

b. fabricating 2-6 layers of said polymer (or material) and disposing said layers so as to create an optical waveguide for a CHIP waveguide core;

c. wherein photoexposed regions results in crosslinking of the polymer

(e.g. CHIPs material), rendering said regions insoluble in solvents that can rinse away the uncured polymer (or material), resulting in a physically defined waveguide core; and

(B) An optical waveguide made using A.

[0060] In further embodiments, the invention encompasses multilayer device comprising at least one layer of poly(S-r-CHIP), wherein said device comprises:

(A) at least a portion of the area of the layer which has been photoexposed by a method comprising using a mask or a maskless lithography system to create a photopattern, which comprises an unexposed region and an photoexposed region, thereby fabricating at least one layer of said polymer so as to create an optical waveguide, wherein said photoexposed regions results in crosslinking of the polymer (or CHIP material), rendering said regions insoluble into solvents that can rinse away the uncured material (or polymer), resulting in a physically defined waveguide core; and

(B) An optical waveguide made using said method (A).

[0061] In further embodiments, the invention encompasses a multilayer device

comprising at least one layer of poly(S-r-CHIP), wherein said device comprises:

(A) at least a portion of the area of the layer which has been photoexposed by a method comprising using a mask or a maskless lithography system to create a photopattern, which comprises an unexposed region and an photoexposed region, thereby fabricating at least one layer of said polymer so as to create an optical waveguide, wherein said photoexposed region results in crosslinking of the polymer (or CHIP material), rendering said region insoluble into solvents that can rinse away the uncured material, resulting in a physically defined waveguide core; and

(B) An optical waveguide made using said method (A).

[0062] Without wishing to limit the invention to a particular theory or mechanism, when the poly(S-r-DIB) is exposed to ultraviolet radiation and any developmental- or solvent-washing step the refractive index of the polymer is reduced. Aromatic solvents, such as, toluene, chlorobenzene, dicholorobenzene, and nonpolar aprotic solvents, such as, tetrahydrofuran, or dichloromethane may be used in the solvent washing step. The irradiated polymer has a refractive contrast with virgin polymer that allows the material to be used for optical waveguide architectures and devices. Conventional photolithography processes, currently used in microelectronic technology, can easily be applied to this polymer, enabling its use in the thin film market. [0063] The photoresponsive medium of the invention may be used in standard photolithography processes. For example, the photoresponsive medium may be used in optical packaging applications. In some embodiments, the invention encompasses an optical packaging comprising photoresponsive medium of the invention. [0064] In further embodiments, the optical waveguide of the invention may be used in a photonic device. The photonic device may be used to perform guiding, coupling, switching, splitting, multiplexing and/or demultiplexing of optical signals. Photonic devices as described herein may be assembled using known methods.

[0065] In some embodiments, the photonic device is a waveguide device such as integrated splitter, coupler, arrayed waveguide grating, or optical waveguide amplifier. In other embodiments, the polymer waveguide devices is used as optical interconnects (i.e., coupling two discrete optical elements or devices). Waveguide devices as described herein may be assembled using known methods. See e.g., US Patent 6,917,749. [0066] Chalcogenide Hybrid Inorganic/Organic Polymers (CHIP)

[0067] In some embodiments, CHIP is prepared from one or more chalcogenic monomers. The chalcogenic monomer may be selected from a group consisting of elemental sulfur, a liquid polysulfide, an oligomer containing sulfur, and an oligomer containing sulfur and selenium units. In further embodiments, the chalcogenic monomers may comprise sulfur monomers derived from elemental sulfur, and elemental selenium (Se8) or selenium sulfide, or a combination thereof. [0068] In further embodiments, the chalcogenic monomers may comprise one or more cyclic selenium sulfide monomers having the formula Se_nS(8-n). In another embodiment, the cyclic selenium sulfide monomers can include any isomer of the formula. In some embodiments, n in an integer that can range from 1 to 7. For example, when n=2, the cyclic selenium sulfide monomers have the formula Se2S6. As another example, when n=3, the cyclic selenium sulfide monomers have the formula SesSs. Preferably, the one or more cyclic selenium sulfide monomers can comprise all possible isomers of a specific formula. In alternative embodiments, the selenium sulfide monomers can be of the formula Se_nS_m, wherein n ranges from 1 to 7 and m ranges from 1 to 7, wherein the selenium sulfide monomers are not necessarily cyclic. In one embodiment, assuming that n=7, i.e. Se7S, then the cyclic selenium sulfide monomers may comprise at most about 70 wt% of selenium.

[0069] In some embodiments, the CHIP may comprise one or more sulfur monomers derived from elemental sulfur at a level of at least 35 wt% of the CHIP, elemental selenium (See) at a level of at least 35 wt% of the CHIP, and one or more comonomers each selected from a group consisting of amine comonomers, thiol comonomers, sulfide comonomers, alkynylly unsaturated comonomers, epoxide comonomers, nitrone comonomers, aldehyde comonomers, ketone comonomers, thiirane comonomers, ethylenically unsaturated comonomers, styrenic comonomers, vinylic comonomers, methacrylate comonomers, acrylonitrile comonomers, allylic monomers, acrylate monomers, vinylpyridine monomers, isobutylene monomers, maleimide monomers, norbornene monomers, norboradiene monomers, norbornadiene based monomers, monomers having at least one vinyl ether moiety, and monomers having at least one isopropenyl moiety, at a level in the range of about 5-50 wt% of the CHIP.

[0070] In one embodiment, for example, the CHIP may comprise at least about 50 wt% of the sulfur monomers. In another embodiment, the CHIP may comprise at least about 50 wt% of See. In a further embodiment, the CHIP may comprise about 35- 50 wt% of sulfur monomers, about 35-50 wt% of elemental selenium, and about

15-25 wt% of the comonomers.

[0071] In some embodiments, any of the CHIP described herein may further comprise at least about 35 wt% of chalcogenic monomers. In other embodiments, the chalcogenic monomers can be at a range of about 35 to 50 wt%, or about 50 to 60 wt%, or about 60 to 70 wt%, or about 70 to 80 wt%, or about 80 to 99 wt% of the CHIP. [0072] In other embodiments, the CHIP may comprise one or more chalcogenic monomers at a level of at least 35 wt% of the CHIP, and one or more one or more triazine and/or phosphazene moieties, at a level in the range of about 5-50 wt% of the CHIP. In one embodiment, the chalcogenic monomers are may comprise elemental sulfur, a liquid polysulfide, a liquid chalcogenide polymer, an oligomer containing sulfur, an oligomer containing sulfur and selenium units, or a combination thereof.

[0073] In one embodiment, any of the CHIP may comprise one or more cyclic selenium sulfide monomers at a range of about 5 to 10 wt%, or about 10 to 20 wt%, or about 20 to 30 wt%, or about 30 to 40 wt%, or about 40 to 50 wt%, or about 50 to 60 wt%, or about 60 to 70 wt% of the CHIP. In another embodiment, the cyclic selenium sulfide monomers may comprise selenium units of at most about 20 wt%, or at most about 30 wt%, or at most about 40 wt% or at most about 50 wt%, or at most about 60 wt%, or at most about 70 wt% of the cyclic selenium sulfur monomers. In a further embodiment, the cyclic selenium sulfide monomers comprises at most about 70 wt% of selenium.

[0074] In some embodiments, any of the CHIP may further comprise about 5-50 wt% of chalcogenic monomers. In other embodiments, the chalcogenic monomers can be at a range of about 5 to 10 wt%, or about 10 to 20 wt%, or about 20 to 30 wt%, or about 30 to 40 wt%, or about 40 to 50 wt% of the CHIP. [0075] In other embodiments, any of the CHIP described herein may comprise the one or more comonomers are at a range of about 5 to 10 wt%, or about 10 to 20 wt%, or about 20 to 30 wt%, or about 30 to 40 wt%, or about 40 to 50 wt% of the CHIP.

[0076] In other embodiments, any of the CHIP may further comprise about 5-50 wt% of elemental sulfur (Ss). In other embodiments, the elemental sulfur can be at a range of about 5 to 10 wt%, or about 10 to 20 wt%, or about 20 to 30 wt%, or about 30 to 40 wt%, or about 40 to 50 wt% of the CHIP. [0077] In still other embodiments, any of the CHIP may further comprise about 5-50 wt% of elemental selenium (See). In further embodiments, the elemental selenium can be at a range of about 5 to 10 wt%, or about 10 to 20 wt%, or about 20 to 30 wt%, or about 30 to 40 wt%, or about 40 to 50 wt% of the CHIP. [0078] In some embodiments, any of the CHIP comprises at least about 50 wt% sulfur monomers. In other embodiments, the one or more comonomers are at a range of about 5 to 10 wt%, or about 10 to 20 wt%, or about 20 to 30 wt%, or about 30 to 40 wt%, or about 40 to 50 wt% of the CHIP. In still other embodiments, the CHIP may further comprise at least about 35 wt%, or at least about 40 wt%, or at least about 50 wt% of elemental selenium (See).

[0079] CHIP and methods as disclosed in Int’l Appl. No. PCT/US18/25178; filed:

March 29, 2018 is incorporated by reference to the extent it is consistent with the aspects of the invention described herein. [0080] The following list of embodiments are mentioned by way of example:

1. A photoresponsive medium comprising one or more CHIPs. The CHIPs photoresponsive medium has the property of changing its refractive index upon the application of certain wavelengths of radiation, preferably in the ultraviolet between 350-400nm, with the amount of refractive index change proportional to the duration of the illumination.

2. Substrate deposited films, or thin films using CHIPs material ranging from 10 nm to 20 mΐti thick that can be selectively crosslinked by photoirradiation with ultraviolet light through a photomask, or via a maskless lithography process with feature sizes of the photopatterned CHIPs ranging from 10 nm to 100 mΐti. 3. A method of preparing a photopatterned, unstructured polymer thin film, said method comprising photopatterning unstructured polymer thin films of one or more CHIPs based on poly(sulfur-random-(1 ,3-diisopropenylbenzene) (poly(S- r DIB), or other CHIPs compositions based organic unsaturated comonomers, by exposure with ultraviolet radiation without any development, or solvent washing steps required to obtain a refractive index contrast in the polymer. 4. An optical waveguide fabricated by solution processing of CHIPs materials into thin films, photopatterning and developing to create a physically defined CHIPs waveguide core, with lower refractive index materials suitably disposed around the patterned CHIPs waveguide core. 5. A multilayer device comprising at least one layer of chalcogenide-based polymer (e.g. a CHIP material), wherein said device comprises:

(B) An optical waveguide made using said method (A).

6. A multilayer device including a layer of chalcogenide-based polymer, e.g. a CHIPs material, wherein said device comprises:

(A) at least a portion of the area of the layer which has been photoexposed by a method comprising

(B) using mask or with a maskless lithography system to create a

photopattern;

(C) fabricating 2-6 layers of said polymer (or material) and disposing said layers so as to create an optical waveguide for a CHIP waveguide core;

(D) wherein photoexposed regions results in crosslinking of the polymer (e.g. CHIPs material), rendering said layers insoluble into solvents that can rinse away the uncured material, resulting in a physically defined waveguide core; and

(E) An optical waveguide made using A. 7. A multilayer device comprising at least one layer of poly(S-r-CHIP), wherein said device comprises: (A) at least a portion of the area of the layer which has been photoexposed by a method comprising using a mask or a maskless lithography system to create a photopattern, which comprises an unexposed region and an photoexposed region, thereby fabricating at least one layer of said polymer so as to create an optical waveguide, wherein said photoexposed region results in crosslinking of the polymer (or

CHIP material), rendering said region insoluble in solvents that can rinse away the uncured polymer (or material), resulting in a physically defined waveguide core; and

(B) An optical waveguide made using said method (A).

[0081] EXAMPLES

[0082] Example 1

[0083] S-DIB Waveguide Fabrication Processes Overview

[0084] Several methods have been developed for forming waveguides in poly (S-r- DIB) and its counterparts. Ultraviolet (UV) light may be used to form the waveguides as follows:

[0085] (a) Ultraviolet light can be used in conjunction with a light-field mask to expose the polymer in regions surrounding the intended location of the waveguide core, resulting in a reduction in refractive index of more than 0.02 at 1550 nm wavelength.

[0086] (b) UV light can also be used in conjunction with an appropriate photomask to make the material insoluble in common solvents, thereby enabling the direct creation of physical waveguide structures without the need for expensive etching processes. Photobleaching

[0087] In the photobleaching waveguide process the poly (S-r-DIB) is spin-coated onto a suitable lower cladding layer such as Si0₂ or the partially fluorinated optical polymer ZPU. The film is then exposed to broadband UV radiation (300-400 nm) through a light-field lithography mask; the regions that are not blocked by mask features experience a reduction in refractive index when the appropriate amount of radiation is delivered. The detailed process conditions to achieve waveguides with good confinement are as follows: a. dissolve 50/50 S-DIB in dichlorobenzene at 1 15 °C (1g/2ml_ concentration) b. spin onto Si0₂/Si wafers at 3000 RPM for 30 seconds (~1.5 mΐti film) c. bake at 105 °C for 3 minutes d. Using a light-field photomask, the films were exposed with a broadband UV source (18 mW/cm² @ 365nm) for 4.5 hrs e. exposed regions show a reduction in the refractive index, such that Dh - 0.02 Photocuring

[0088] Under different conditions, broadband UV radiation can actually be used to crosslink the poly(S-r-DIB), making it insoluble in its typical solvents. The lithography is then performed using a dark-field lithography mask, such that the exposed regions are crosslinked and remain as rib waveguides when the uncured material is removed with solvent. A typical procedure is as follows: i. dissolve 50/50 S-DIB in dichlorobenzene at 1 15 °C (1g/4ml_ concentration) ii. spin-coat onto Si0₂(6 mΐti)/3ί wafers at 1 5K/30secs (-750 nm film) iii. bake at 105 °C for 2min iv. purge the samples in N₂ (-30 psi) for 10-15min v. using a dark-field photomask, the films are exposed with a broadband UV source (30 mW/cm² @365 nm) for 10 minutes; the exposed regions are crosslinked and insoluble in the solvent vi. develop in tetrahydrofuran (THF) or chlorobenzene for 20 seconds vii. plasma treatment for 30 seconds viii. spin top cladding layer, ZPU, at 2.5K for 30sec and then UV cure for 10min to achieve 3 mΐti thick top cladding

[0089] Example 2

[0090] UV induced refractive index change

[0091] The data in Figures 1 -3 was obtained using the following procedures:

[0092] Sample A and B were exposed under broadband UV lamp (~14mW/cm², peak wavelength = 365 nm) for 3.5 and 4 hours respectively in atmospheric conditions, while monitoring the temperature of the chamber. The samples were half covered with Al foil during exposure. The 50/50 S-DIB films are ~1.6um thick on Si wafer.

[0093] The exposed/unexposed area was clearly distinguishable after exposure.

[0094] Index was measured between the two areas.

[0095] The samples were then left in dark for almost two weeks.

[0096] Samples were then kept on a hotplate set at 100C for 24 hours and the index was measured again. The results are shown below (Significant to 2 decimals)

[0097] Summary: The refractive index of 50/50 S-DIB films can be changed by amounts useful for optical waveguiding (-0.02) by exposing the film to UV radiation of 10-20 mW/cm² for several hours

[0098] Example 3

[0099] UV induced refractive index change

[00100] The data in Figure 4 was obtained using the following procedures: [00101] Samples C and D were prepared by spinning 50/50 S-DIB on glass slides (1.6um thick). Sample C was left unexposed and Sample D was exposed under UV lamp for 4.5 hours.

[00102] Films were then characterized with UV-Vis spectrometer. The result is shown in Figure 4.

[00103] The spectra show that there is a feature in the 500nm region that disappears upon bleaching; the elimination of this feature, which is due to absorption, causes changes in the refractive index, that manifest themselves as shifts in the spectrum in the transparency region (i.e. > 700nm), where the oscillations are due to thin film interference.

[00104] Example 4

[00105] Waveguide (WG) Fabrication

[00106] The data in Figures 5-6 was obtained using the following procedures:

[00107] An optical waveguide (WG) was fabricated in the sulfur-based polymer by using a photomask together with a UV radiation source - the regions exposed to UV defined the side-cladding regions of the waveguide, while the unexposed area between them had higher refractive index. The bottom cladding was silicon dioxide and the top was air.

[00108] S-DIB was spun at 2300 rpm/30sec on a Single Side Polished (SSP) Si wafer with silica cladding. The film then was baked at 100 °C for 3 minutes.

[00109] The sample was placed under photomask. Mask had straight WG structures varying in width from 2-7um, with 2 sets of each waveguide.

[001 10] The core region of the waveguide structure was covered and rest of the area was exposed. [001 1 1] The sample was kept in the ELC150 UV curing chamber for 5 hours.

[001 12] Example 5

[001 13] The data in Figure 8 was obtained using the following procedures (see Figure 7):

[001 14] Coupled the fiber to 3um WG and observed the modes shown in the infrared camera image of Figure 8 by collimating the waveguide output with a microscope objective. [001 15] The total insertion loss for each sample was measured. This was performed by first measuring the initial power by bringing the optical fiber delivering the light up to the measuring power meter. Then the optical fiber is aligned with the waveguide sample and the output image observed on the camera until a good optical mode is obtained. The light is then sent directly into the power meter and the input fiber aligned to optimize the power measured. In a typical case the intial power coming out of the optical fiber was measured to be -3.4dBm, and the power measured coming from the WG#1 was -13.6dBm, giving an insertion loss of 10.2dB. For WG#2 with an output power of -13.4dBm, the insertion loss was 10dB. This is the total insertion loss of the waveguide, which includes both coupling loss from the optical fiber to the waveguide and propagation loss in the waveguide. The waveguide sample is then diced to a shorter length and the entire procedure repeated. This is done for typically 4 waveguide lengths, and then the insertion loss is plotted vs. length, which allows determination of both propagation loss (slope) and coupling loss (intercept). [001 16] Example 6

[001 17] The data in Figures 10-12 was obtained using the following:

(a) 1550 nm DFB laser was butt coupled to WG facet. Output light was collimated by objective lens and measured w/ optical power meter. The following conditions were used: · Input power: 0 dBm

• Background power (Fiber to lens): -7.01 dBm

• Insertion loss (= Total o/p power - Background power) was plotted against length [00118] Results: • propagation loss: -3.02dB/cm, -1.71dB/cm, -2.61dB/cm

• coupling loss: -12.8dB, -9.27dB, -9.42dB

[00119] Conclusion: WG#1 and WG#3 were close to the edge of the chip which is why the loss is higher [00120] REFERENCES

[00121] A number of patents and publications are cited above in order to more fully describe and disclose the invention and the state of the art to which the invention pertains. Full citations for these references are provided below. Each of these references is incorporated herein by reference in its entirety into the present disclosure, to the same extent as if each individual reference was specifically and individually indicated to be incorporated by reference.

Claims

WHAT IS CLAIMED IS:

1. A photoresponsive medium comprising one or more CHIPs, wherein the photoresponsive medium changes its refractive index upon the application of ultraviolet radiation between 350-400nm.

2. A method of preparing a photopatterned, unstructured polymer thin film, said method comprising depositing on to a substrate the unstructured polymer film comprising one or more CHIPs and exposing said film to ultraviolet radiation to form an exposed CHIP film.

3. An exposed CHIP film according to claim 2, wherein said film has a thickness ranging from 10 nm to 20 pm.

4. An exposed CHIP film according to claim 2wherein said film is prepared by a photopatterning method comprising selectively crosslinking by photoirradiation with ultraviolet light through a photomask, or via a maskless lithography process with feature sizes of the photopatterned CHIPs ranging from 10 nm to 100 pm.

5. An optical waveguide fabricated by a method comprising solution processing of CHIPs to form a thin film deposited on a substrate, photopatterning the film, and, optionally, adding a top layer, to form an optical waveguide which is capable of transmitting infrared radiation through the CHIPs film.

6. A method of fabricating the optical waveguide of claim 5 comprising solution processing of CHIPs materials into thin films, and photopatterning said film.

7. A multilayer device comprising at least one layer of chalcogenide-based polymer (e.g. a CHIP material), wherein said device comprises:

(A) at least a portion of the area of the layer which has been photoexposed by a method comprising using a mask or a maskless lithography system to create a photopattern, which comprises an unexposed region and an photoexposed region, thereby fabricating at least one layer of said polymer so as to create an optical waveguide, wherein said photoexposed region results in crosslinking of the polymer (or CHIP material), rendering said region insoluble in solvents that can rinse away the uncured polymer (or material), resulting in a physically defined waveguide core; and

(B) An optical waveguide made using said method (A).

8. A multilayer device including a layer of chalcogenide-based polymer, e.g. a CHIPs material, wherein said device comprises:

(B) using mask or with a maskless lithography system to create a

photopattern;

(D) wherein photoexposed regions results in crosslinking of the polymer (e.g. CHIPs material), rendering said layers insoluble into solvents that can rinse away the uncured material (or material), resulting in a physically defined waveguide core; and

(E) An optical waveguide made using A.

9. A multilayer device comprising at least one layer of poly(S-r-CHIP), wherein said device comprises:

(A) at least a portion of the area of the layer which has been photoexposed by a method comprising using a mask or a maskless lithography system to create a photopattern, which comprises an unexposed region and an photoexposed region, thereby fabricating at least one layer of said polymer so as to create an optical waveguide, wherein said photoexposed region results in crosslinking of the polymer (or CHIP material), rendering said region insoluble into solvents that can rinse away the uncured material (or material), resulting in a physically defined waveguide core; and

(B) An optical waveguide made using said method (A).

10. The device of claim 7 or claim 8, wherein said chalcogenide-based polymer is poly(S-r-CHIP).

1 1 .The device of any of claims 1 , 7, 8, and 9, wherein the CHIP has a content of selenium atoms and sulfur-selenium bonds in the polymer (10-75 wt% Se) with unsaturated organic, inorganic, or hybrid comonomers ranging from 90-10 wt%, where the S-S, or Se-S bonds are also stimuli-responsive and able to form crosslinked films by exposure to heat, mechanical stress or light.

12. The medium of claim 1 , wherein the change to the refractive index is irreversible.

13. The device of any of the preceding claims, wherein the photoexposed region is characterized by a refractive index is up to 1 lower than that of the unexposed region.

14. The medium of claim 12, wherein the photoexposed region is characterized by a refractive index that is 0.01-0.08 lower than that of the unexposed region.

15. The medium of claim 12, wherein the photoexposed region is characterized by a refractive index that is 0.01-0.05 lower than that of the unexposed region.

16. The device of any of the preceding claims, wherein said solvent is an organic solvent.

17. A photonic device comprising a waveguide of claim 5.

18. A waveguide device comprising a waveguide of claim 5.

19. The device of claim 18, wherein said device is an integrated splitter, coupler, arrayed waveguide grating, phase-shifter, Mach-Zehnder interferometer, directional coupler, microring resonator, or mode converter.