Dazzling effect: White light emitters for LED by IIT Madras team

The successful research team

Indian Institute of Technology Madras researchers have successfully developed a white light emitter for use in LEDs. The development of energy-efficient Light Emitting Diodes or LEDs replaced the energy-inefficient incandescent lamps in lighting and display applications. While LEDs have been available in almost all colours, white LEDs are a more recent development.

Conventional LED materials cannot emit white light and specialised techniques such as coating blue LED with yellow phosphor and blue, green and red LEDs have been combined to produce white light. Scientists have been looking for materials that can directly emit white light rather than through these indirect techniques that can cause loss of efficiency.

The innovation has been patented by the researchers and was recently granted the government’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 Rs  30 lakh grant money to produce LEDs using distorted perovskite materials.

The research was led by Aravind Kumar Chandiran, assistant professor, department of chemical engineering, IIT Madras, and Ranjit Kumar Nanda B, department of physics, IIT Madras. Explaining the practical applications of this research, Chandiran, said, “The indigenously-developed bright white light emitters can potentially replace the conventional high-cost materials and phenomenally save the energy cost per lumens.”

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. The researchers developed expertise in tuning the material at an atomic level to obtain different properties. Through a recent project that included simulation and experimental work, the team distorted the crystal structure of this material to obtain a natural white light emitter.