Researchers at the Indian Institute of Technology (IIT) Madras have successfully developed a white light emitter for Light Emitting Diodes or LEDs. As conventional LED materials cannot emit white light, specialised techniques such as coating blue LED with yellow phosphor and combining blue, green, and red LEDs were used to produce white light.
There has been a worldwide search for materials that can directly emit white light rather than using these indirect techniques, which often leads to loss of efficiency. "The indigenously-developed bright white light emitters can potentially replace the conventional high-cost materials and phenomenally save the energy cost per lumens," said Dr Aravind Kumar Chandiran, Assistant Professor, Department of Chemical Engineering at IIT Madras.
The team published the research in the prestigious peer-reviewed international journal belonging to the Nature group — Communications Materials. They also proposed a clear design strategy that scientists can employ to develop white light emitters. The team, which has patented the technology, was also granted the Government of India's 'SERB-Technology Translation Award'.
The Science and Engineering Research Board (SERB) provides financial assistance to researchers, academic institutions, research and development laboratories, industrial concerns, and other agencies. The team proposes to use the grant money of Rs 30 lakh to produce LEDs using their distorted perovskite materials. "We believe that our work contributes to the 'Make in India' programme and we hope to become a technology leader in light emitters in the near future," Chandiran said.
The IIT Madras team has been exploring crystalline materials called 'Halide-Perovskites' for various applications due to their extraordinary optoelectronic properties and excellent light-to-current conversion efficiencies.
In a recent project, the team distorted the crystal structure of this material to obtain a natural white light emitter. This distorted perovskite can be used independently as a white light emitter or as a phosphor in combination with blue LEDs to produce white light. Unlike other recently developed white LED materials, this distorted perovskite also showed phenomenal stability under ambient conditions. The emission of intense light and stability make them useful in long-lasting, energy-saving lighting applications.
Apart from general lighting, white LEDs can potentially be used in liquid crystal display backlights, display mobile lighting, and medical and communication equipment, the researchers explained.
Edited by Bidushi Das
