LED Specifications
What is the Peak Emission Wavelength of an LED?

The Peak Emission Wavelength of an LED is the maximum wavelength that the photons that the LED emits can be.

All LEDs emit photons in order to emit light. The wavelength of the photons that an LED emits determines the LED's color. For example, red LEDs have wavelengths of around 633 to 660 nanometers, depending on whether it's super red, high efficiency red, or ultra red. The wavelength determines the color and brightness of an LED.

On a datasheet for an LED, you can get a feel for the characteristics of an LED by viewing 2 characteristics of the LED, its dominant wavelength, which is the the wavelength the LED emits the majority of the time, and its peak emission wavelength, which is the maximum wavelength that the LED may achieve at times. These two characteristics shouldn't vary much.

The peak emission wavelength is a specification that shows that the LED can hit a higher wavelength than its typical wavelength, and serves as a maximum number. The difference in wavelength values can vary the color slightly and usually not enough to be noticeable.

The peak emission wavelength is not a specification that an typical user of LEDs needs to be concerned with.