A Systematic Approach to Achieving High Performance Hybrid Lighting Phosphors with Excellent Thermal- and Photostability

• Published in: Advanced functional materials Vol. 27; no. 3
• Main Authors: Fang, Yang, Liu, Wei, Teat, Simon J., Dey, Gangotri, Shen, Zeqing, An, Litao, Yu, Dechao, Wang, Lu, O'Carroll, Deirdre M., Li, Jing
• Format: Journal Article
• Language: English
• Published: United States Wiley 07.12.2016
• Subjects: MATERIALS SCIENCE
• ISSN: 1616-301X; 1616-3028

We have designed and synthesized a family of high-performance inorganic-organic hybrid phosphor materials composed of extended and robust networks of one-, two- and three-dimensions. Following a bottom-up solution-based synthetic approach, these structures are constructed by connecting highly emissive Cu4I4 cubic clusters via carefully selected ligands that form strong Cu-N bonds. They emit intensive yellow-orange light with high luminescence quantum efficiency, coupled with large Stokes shift which greatly reduces self-absorption. They also demonstrate exceptionally high framework- and photo-stability, comparable to those of commercial phosphors. The high stabilities are the result of significantly enhanced Cu-N bonds, as confirmed by the DFT binding energy and electron density calculations. Possible emission mechanisms are analyzed based on the results of theoretical calculations and optical experiments. Two-component white phosphors obtained by blending blue and yellow emitters reach an internal quantum yield (IQY) as high as 82% and correlated color temperature (CCT) as low as 2534 K. The performance level of this sub-family exceeds all other types of Cu-I based hybrid systems. The combined advantages make them excellent candidates as alternative rare-earth element (REE) free phosphors for possible use in energy-efficient lighting devices.