Synthesis and characterization of thianthrene-based epoxy with high refractive index over 1.7

The Properties, Synthesis, and Materials Applications of 1,4-Dithiins and Thianthrenes

1,4-Dithiin and its dibenzo-analogue, thianthrene, represent a class of non-aromatic, sulfur-rich heterocycles. Their unique properties, stemming from both their non-planar structures and reversible one- and two-electron oxidations, serve as primary motivators for their use in the development of new materials. The applications of 1,4-dithiins and thianthrenes are rich and diverse, having been used for energy storage and harvesting, and the synthesis of phosphorescent compounds and porous polymers, among other uses. This review offers first an overview of the properties of 1,4-dithiin and thianthrene. Next, we describe enabling synthetic methodology to access 1,4-dithiins and thianthrenes with various substitution patterns. Lastly, the utility of 1,4-dithiin and thianthrene in the construction and design of new materials is detailed using select literature examples.

1 Introduction

2 Properties of 1,4-Dithiins and Thianthrenes

3 Synthesis of 1,4-Dithiins and Thianthrenes

3.1 Synthesis of 1,4-Dithiins

3.2 Synthesis of Thianthrenes

4 Application of 1,4-Dithiins and Thianthrenes in Materials

4.1 Thianthrene-Containing Polymers

4.2 Thianthrene in Redox-Active Materials

4.3 Thianthrenes and 1,4-Dithiins in Supramolecular Chemistry and Self-Assembly

4.4 Thianthrenes in Phosphorescent Materials

4.5 Thianthrenes with Other Interesting Photophysical Properties

4.6 Thianthrenes in the Synthesis of Non-natural Products

5 Conclusion

High Refractive Index Diphenyl Sulfide Photopolymers for Solar Cell Antireflection Coatings

The anti-reflection film can effectively reduce the surface reflectivity of solar photovoltaics, increase the transmittance of light, and improve the photoelectric conversion efficiency. The high refractive index coating is an important part of the anti-reflection film. However, the traditional metal oxide coating has poor stability and complicated processes. To address this issue, we prepared two organic high refractive index (HRI) photopolymers by modifying epoxy acrylic acid with 4,4′-thiodibenzenethiol, which can be surface patterned by nanoimprinting to prepare antireflection coatings. As a result, two modified photopolymers with high refractive index (n > 1.63), high optical transmittance (T > 95%), and thermal stability (Tg > 100 °C) are obtained after curing. In particular, the diphenyl sulfide photopolymer modified by ethyl isocyanate acrylate has a refractive index up to 1.667 cured by UV light. Our work confirms that the organic HRI photopolymer can be obtained by introducing high molar refractive index groups, with potential to be applied as a PV cell power conversion efficiency material.