HIGH REFRACTIVE INDEX AND HIGHLY BIREFRINGENT SOLID ORGANIC MATERIALS
An organic thin film includes an organic solid crystal material and has mutually orthogonal refractive indices, n x , n y , n z , each having a value at 589 nm of between 1.5 and 2.6, with Δn xy <Δn xz <Δn yz , where the organic solid crystal material includes an organic molecule selected from 1,2,3-trichlorobenzene, 1,2-diphenylethyne, phenazine, terphenyl, 1,2-bis(4-(methylthio)phenyl)ethyne, and anthracene. The organic thin film may be birefringent and may be configured as a single layer thin film, or plural organic thin films may be stacked to form a multilayer that may be incorporated into an optical element, such as a reflective polarizer.
1 . An organic thin film comprising an organic solid crystal material, the organic thin film having mutually orthogonal refractive indices (n x , n y , n z , wherein n), n y , and n z each have a value at 589 nm of between approximately 1.5 and approximately 2.6, and Δn xy <Δn xz <Δn yz , wherein the organic solid crystal material comprises an organic molecule selected from the group consisting of 1,2,3-trichlorobenzene, 1,2-diphenylethyne, phenazine, terphenyl, 1,2-bis(4-(methylthio)phenyl)ethyne, and anthracene.
2 . The organic thin film of claim 1 , wherein the organic solid crystal material comprises a single crystal.
3 . The organic thin film of claim 1 , wherein the organic solid crystal material comprises a polycrystalline material.
4 . The organic thin film of claim 1 , wherein the organic solid crystal material comprises a glassy material having molecules aligned along predetermined directions.
5 . The organic thin film of claim 1 , wherein the organic solid crystal material comprises a dopant.
6 . The organic thin film of claim 1 , wherein n z is at least approximately 1.8 across the visible spectrum and the organic thin film has an out-of-plane birefringence of at least approximately 0.2.
7 . The organic thin film of claim 1 , wherein the organic solid crystal material is at least approximately 80% crystalline.
8 . The organic thin film of claim 1 , wherein the organic thin film has a surface roughness (R a ) of approximately 2 nm to approximately 100 nm over an area of at least approximately 1 cm 2 .
9 . An organic thin film comprising an organic solid crystal material, the organic thin film having mutually orthogonal refractive indices (n x , n y , n z , wherein n x , n y , and n z each have a value at 589 nm of between approximately 1.5 and approximately 2.6, and n x =n y ≠n z , wherein the organic solid crystal material comprises an organic molecule selected from the group consisting of 1,2,3-trichlorobenzene, 1,2-diphenylethyne, phenazine, terphenyl, 1,2-bis(4-(methylthio)phenyl)ethyne, and anthracene.
10 . The organic thin film of claim 9 , wherein the organic solid crystal material comprises a single crystal.
11 . The organic thin film of claim 9 , wherein n z is at least approximately 1.8 across the visible spectrum and the organic thin film has an out-of-plane birefringence of at least approximately 0.2.
12 . The organic thin film of claim 9 , wherein the organic solid crystal material is at least approximately 80% crystalline.
13 . The organic thin film of claim 9 , wherein the organic thin film has a surface roughness (R a ) of approximately 2 nm to approximately 100 nm over an area of at least approximately 1 cm 2 .
14 . A method comprising:
forming an organic solid crystal thin film comprising an organic solid crystal material over a surface of a substrate, the organic solid crystal thin film having mutually orthogonal refractive indices (n x , n y , n z , wherein n x , n y , and n z each have a value at 589 nm of between approximately 1.5 and approximately 2.6, and n x ≠n y ≠n z .
15 . The method of claim 14 , wherein the surface of the substrate is non-planar.
16 . The method of claim 14 , wherein forming the organic solid crystal thin film comprises:
dispensing an organic precursor material over the surface of the substrate, and locally cooling the organic precursor material to form the organic solid crystal thin film.
17 . The method of claim 16 , further comprising forming a functional layer over the surface of the substrate prior to dispensing the organic precursor material.
18 . The method of claim 16 , wherein locally cooling the organic precursor material comprises zone annealing.
19 . The method of claim 14 , further comprising separating the organic solid crystal thin film from the substrate.
20 . The method of claim 14 , further comprising treating a surface of the organic solid crystal thin film, wherein treating the surface comprises diamond turning.