What Are Light Emitting Diodes (LEDS) and Why Are They Prized as Light Sources?

Context: 

Light-Emitting Diodes (LEDs) to succeed the incandescent bulbs and fluorescent lamps of previous centuries as the world’s light source of choice.

Invention of Blue LEDs Wins Physics Nobel

• In October 2014, the Royal Swedish Academy of Sciences celebrated the advancements in lighting technology by awarding the Nobel Prize in Physics for developing light-emitting diodes (LEDs). 

Also Refer: Nobel Prize Winners 2023 List, Name And Fields

About Light Emitting Diodes (LEDs):

• Light Emitting Diodes (LEDs): Are semiconductor devices that can emit light when an electric current passes through it.
• Diode: It is an electronic component that allows current to flow in only one direction. 
• Semiconductors: They are materials which have a conductivity between conductors (generally metals) and nonconductors or insulators (such as most ceramics).

Working of LEDs

• Basis: It is based on the electroluminescence effect in which the energy released corresponds to visible light frequencies.
  • Electroluminescence refers to the generation of light resulting from the interaction between an electric field and a solid material.
• Follows Haitz’s Law: It asserts that the expense per unit of light emitted by an LED will decrease by 10 times, and the light output will increase by 20 times for a specific light frequency over each decade.
• Blue Light: An LED has four important parts: die, substrate, phosphor, and lens. The “die” is a special part made of gallium nitride (GaN), and it gives off blue light when electricity is sent through it.

Significance of LEDs

• Higher Efficiency: LEDs are more efficient, durable, and have better contrast than incandescent and fluorescent lights which contributes to cost savings. 
• LEDs emit light in a specific direction, unlike incandescent and CFL, which emit light and heat in all directions.
• Higher Durability: LED’s are more durable with higher light contrast (up to 300 lumens amount of visible light emitted per second) which further reduces material waste. 

News Source: The Hindu