One-step synthesis of sulfur-based ultra-high refractive index (n > 1.97) polymer thin film without phase separation

Abstract

The high refractive index polymers (HRIPs) have been developed as a strong candidate of materials for high refractive index (RI) thin films due to low cost, good processability, light weight, and high flexibility. However, developed up to date HRIPs have some limitations for optical applications such as relatively low refractive index and strong absorption in the blue light region, and limited film formation methods. We have developed new sulfur-based polymer film, poly (sulfur-co-divinyl benzene) (pSDVB-sCVD), with high sulfur content about 85 wt% through a one-step synthesis process, termed sulfur chemical vapor deposition (sCVD). which showed ultra-high RI (n＞1.97). The vapor phase process suppressed the formation of long polysulfide chains and made homogenous mixture of sulfur and DVB, there was no phase separation even though high sulfur content. The developed HRIPs film with outstanding optical properties will expand the application fields of HRIPs as optical materials.