Optoelectronics refers to the study and application of devices that can convert electrical energy into light energy and vice versa. One of the most common and widely used optoelectronic devices is the Light-Emitting Diode (LED). LEDs are semiconductor devices that emit light when an electric current passes through them. They are made of a specially designed p-n junction, typically using materials such as gallium arsenide (GaAs) or gallium nitride (GaN).

LEDs offer numerous advantages over traditional incandescent or fluorescent bulbs. They are more energy-efficient, have a longer lifespan, and can be easily controlled for different colors. LEDs are commonly used in various applications, including lighting, displays, signage, and indicators.

Another significant optoelectronic device is the Photovoltaic (PV) cell, commonly known as a solar cell. PV cells are made of semiconductor materials that generate a voltage difference when exposed to light. This phenomenon is known as the photovoltaic effect. When light energy strikes the PV cell, it displaces electrons in the material, creating a flow of current.

PV cells are used in solar panels to convert sunlight into electricity. They have become increasingly popular in renewable energy systems, providing a sustainable and environmentally friendly source of power. PV cells are widely employed in applications such as residential and commercial solar power systems, solar calculators, and even space satellites.