LED (LED)

LED stands for light-emitting diode, a solid-state lighting technology in which electric current flowing across a forward-biased semiconductor junction releases energy as photons. The dominant light-producing junction in white LEDs is gallium nitride (GaN) on a sapphire or silicon-carbide substrate, with a yellow-emitting phosphor (typically cerium-doped yttrium aluminium garnet) coating the chip to produce broad-spectrum white light.

Composition by mass: A typical 9 W Indian LED bulb weighs roughly 110-140 grams. Of this, roughly 55-65% is the aluminium heatsink, 15-20% is the polycarbonate diffuser, 10-15% is the driver PCB (with capacitors, an aluminium electrolytic stack, and a controller IC carrying small amounts of gold and tin-silver solder), 3-5% is the steel screw base, and well under 1% is the LED chips themselves. The LED chips collectively contain a few milligrams of gallium, trace indium, and 5-15 mg of rare earth phosphor — small quantities individually but meaningful when aggregated across tens of millions of lamps.

Why LEDs need responsible end-of-life handling: Unlike CFLs, LEDs are mercury-free, so they are not classified as hazardous e-waste under the E-Waste (Management) Rules, 2022. However, the driver electronics contain electrolytic capacitors with non-recyclable organic electrolytes, and the heatsink-PCB assembly is a composite that resists simple sorting. India's official approach treats LED lamps as electrical and electronic equipment requiring producer EPR obligations: every LED brand placed in the market must register and meet annual collection targets.

Recycling pathway and trade-offs: The aluminium heatsink is the dominant economic recovery (Rs 150-180 per kg at scrap gate); the PCB is processed for copper and trace gold via standard PCB hydrometallurgical routes; the phosphor and chip are typically landfilled because rare-earth phosphor recovery is not economic below several tonnes of feed. The crossover challenge is that LED lifetimes of 15,000-25,000 hours mean returns are slow — the bulbs sold during India's 2015-2018 UJALA distribution programme are only now beginning to fail and enter the e-waste stream in volume.