Britannica Sources used in this answer

How does intrinsic electroluminescence differ from charge-injection electroluminescence?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

energy levels of a luminescent centre — luminescence Figure 1: Energy levels of a luminescent centre (see text).

The primary distinction between intrinsic and charge-injection electroluminescence lies in the role of electric current during the light-production process.1

Intrinsic Electroluminescence

In intrinsic electroluminescence, no net electric current passes through the phosphor material. Instead, an electric field and thermal activation liberate electrons into the conduction band. These electrons are accelerated by the field until they collide with and ionize luminescent centers. Light is emitted when an electron recombines with an ionized atom. Because this effect diminishes under constant voltage, alternating voltage is typically required to sustain light emission.1

Charge-Injection Electroluminescence

In contrast, charge-injection electroluminescence occurs during the passage of an electric current. This process involves injecting electrons or holes into a material, often through an electrode contact or across a p–n junction. As electrons flow from n-type to p-type material, they recombine with holes or centers, releasing energy as light. This mechanism is the fundamental principle behind light-emitting diodes (LEDs).12