A team led by University of Arizona materials scientist Jeffrey Pyun is using a sulfur-based polymer made from waste generated by fossil fuels to develop consumer-grade infrared (IR) plastic lenses. The team has refined this material, which it first used in 2014, to create its second generation of IR lenses.
The new polymers are stronger and more temperature-resistant than the first-generation sulfur plastic developed in 2014, which was transparent to mid-IR wavelengths. The new lenses are transparent to a wider spectral window, extending into the longwave IR, and are far less expensive than the current industry standard of metal-based lenses made of germanium, a heavy, rare, and toxic material.
To strengthen the material without impeding its transparency, the researchers used computational simulations to design organic molecules that were not IR-absorbing and to predict their transparency. The inclusion of organic molecules, while adding needed strength to the sulfur-based material, could also reduce the lens’s transparency since nearly all organic molecules absorb light in the IR-fingerprint region. “It could have taken years to test these materials in the laboratory, but we were able to greatly accelerate new materials design using this method,” researcher Tristan Kleine said.
Using computational methods for their molecular-design approach, the researchers prepared chalcogenide hybrid inorganic/organic polymers (CHIPs) with enhanced LWIR transparency and thermomechanical properties via inverse vulcanization of elemental sulfur with new organic co-monomers.