PT  - JOURNAL ARTICLE
AU  - Kim, Do Heung
AU  - Jang, Wontae
AU  - Choi, Keonwoo
AU  - Choi, Ji Sung
AU  - Pyun, Jeffrey
AU  - Lim, Jeewoo
AU  - Char, Kookheon
AU  - Im, Sung Gap
TI  - One-step vapor-phase synthesis of transparent high refractive index sulfur-containing polymers
AID  - 10.1126/sciadv.abb5320
DP  - 2020 Jul 01
TA  - Science Advances
PG  - eabb5320
VI  - 6
IP  - 28
4099  - http://advances.sciencemag.org/content/6/28/eabb5320.short
4100  - http://advances.sciencemag.org/content/6/28/eabb5320.full
SO  - Sci Adv2020 Jul 01; 6
AB  - High refractive index polymers (HRIPs) have recently emerged as an important class of materials for use in a variety of optoelectronic devices including image sensors, lithography, and light-emitting diodes. However, achieving polymers having refractive index exceeding 1.8 while maintaining full transparency in the visible range still remains formidably challenging. Here, we present a unique one-step vapor-phase process, termed sulfur chemical vapor deposition, to generate highly stable, ultrahigh refractive index (n > 1.9) polymers directly from elemental sulfur. The deposition process involved vapor-phase radical polymerization between elemental sulfur and vinyl monomers to provide polymer films with controlled thickness and sulfur content, along with the refractive index as high as 1.91. Notably, the HRIP thin film showed unprecedented optical transparency throughout the visible range, attributed to the absence of long polysulfide segments within the polymer, which will serve as a key component in a wide range of optical devices.