Increase in Wavelength of an LED Immersed in Liquid Nitrogen

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SUMMARY

The experiment discussed reveals an unexpected increase in the wavelength of light emitted by LEDs when immersed in liquid nitrogen. Initially, a yellow LED transitioned to a greenish hue, followed by a shift back to yellow-orange. This contradicts the common expectation that immersion would result in a decrease in wavelength. The findings suggest a complex interaction between the LED materials and the extreme cold, warranting further investigation into the underlying physics.

PREREQUISITES
  • Understanding of LED technology and semiconductor physics
  • Knowledge of photonics and light wavelength behavior
  • Familiarity with cryogenic environments and their effects on materials
  • Basic principles of color theory related to light emission
NEXT STEPS
  • Research the effects of temperature on semiconductor bandgap energy
  • Explore the principles of photoluminescence in LEDs
  • Investigate the impact of liquid nitrogen on electronic components
  • Study the behavior of light in different mediums at cryogenic temperatures
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Physicists, materials scientists, electrical engineers, and anyone interested in the effects of extreme temperatures on electronic devices.

caleb5040
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Hi,

I've been working on an experiment where I dip LEDs into liquid nitrogen and note the color change. All online sources I've seen predict that the wavelength of the light emitted by the LED will decrease upon immersion.
What I've been observing, however, is a sudden decrease in wavelength followed by a definite increase in wavelength. So, for example, a yellow LED turned green-ish at first, and then rapidly changed to yellow-orange.

I've been looking around for an explanation of why I am getting this (opposite) effect, but haven't had any luck. Does anyone have any ideas?
 
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