EAGER: Discovery of Next Generation Durable Non-toxic Inorganic Red Pigments

Oregon State University, Corvallis OR

Investigators

Abstract

PART 1. NON-TECHNICAL Colors play a vital role in our lives and how we respond to surroundings. Inorganic color pigments are used to generate colors in paints, glass, ceramics and plastics. However, the world has never had a truly safe durable inorganic red pigment. Currenty known inorganic red pigments contain toxic metals such as cadmium, mercury or lead. Driven by environmental laws, these red pigments have to be replaced and discovering a safe durable bright red pigment is the holy grail of colorant producing companies. The central theme of this materials chemistry project, which is supported by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, is the discovery of next generation durable non-toxic bright red inorganic pigments based on transition metal oxides and it’s derivatives that can be used in artist colors, industrial paints and other coating technologies. This project significantly contributes to education and research training for graduate and undergraduate students in the field of solid state materials chemistry. High school students participating in the project gain valuable hands-on research experience and learn the pathways to advanced education and career in STEM disciplines. New materials are drivers of new phenomena and technologies. Designing new materials with superior color properties is a scientific grand challenge, the pursuit of which will provide the basis for new color technologies and revolutionize our society. PART 2. TECHNICAL SUMMARY This exploratory research, supported by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, is aimed at the discovery of new stable bright red inorganic materials that can be used as red color pigments. The focus is on the discovery of complex inorganic materials with unusual structural features. The common coordinations for transition metal cations in inorganic functional materials are tetrahedral and octahedral. Transition metal oxides with cations in trigonal bipyramidal coordination are rare but recently known to produce brilliantly colored blue oxides of considerable scientific and commercial interests as pigments; e.g. YInMn blue. By understanding the crystal structure-optical property relationships for trigonal bipyramidal cations in various complex inorganic oxides, the researchers design new transition metal oxides with red producing chromophores (e.g. chromium) that can be developed into commercially viable red pigments. This project also explores novel mixed oxides, oxyfluorides and oxysulfides with cations containing lone-pair electrons where there is a tin 5s or bismuth 6s band located above the oxygen 2p band and the resulting bandgap are tuned to produce compounds with brilliant yellow, orange and red colors leading to next generation pigments. Designing new materials with superior color properties is a scientific grand challenge, the pursuit of which will provide the basis for new color technologies and revolutionize our society. This project significantly contributes to education and research training for graduate and undergraduate students in the field of solid state materials chemistry. High school students participate in this project as summer interns and gain valuable hands-on research experience and learn the pathways to advanced education and career in STEM disciplines. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.