Conventional LED materials do not emit white light — specialised techniques, such as blue coating, are used to produce white light. Globally, there is a look-out for materials that can emit white light straightaway.

Now, researchers at IIT-Madras have developed a white-light emitter for use in LEDs. A team comprising professors Aravind Chandiran, Ranjit Nanda, Tamilselvan Appadurai, Ravi Kashikar, Poonam Sikarwar and Sudhadevi Antharjanam has been working on crystalline materials called ‘halide perovskites’ for various applications due to their extraordinary opto-electric properties. They developed expertise in tuning the material at an atomic level to obtain different properties.

Supported by a grant from the Science and Engineering Research Board (SERB), government of India, the team has made a ‘distorted crystal structure’ of the Halide Perovskites to get a natural white light emitter. “These materials show at least eight times intense white light emission compared with the conventional emitters,” says Chandiran.

Unlike other recently developed white LED materials, this distorted perovskite showed phenomenal stability under ambient conditions, says Chandiran.

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.

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