Talk:Light-emitting diode

First we might need clarification as to what LED refers to. Is it:

• is it a single crystal (i.e. a single P-N junction)
• is it an electronic component, which in most cases includes a single PN junction but can include more than one (e.g a bicolor LED), or include a resistor for current limitation (hence the rating of some LEDs as 5V for instance).

For the rest of this comment I am going to assume an LED is a single P-N junction.

Regarding reverse voltage: Most if not all LED manufacturers will list an absolute maximum reverse voltage as 5V. Yet, many people are driving LEDs directly from an AC power line (120V or 240V) with a resistor for current limiting. And in this case, an LED is subjected to a reverse voltage of √2 x 240 ≈ 339V at its peak, a much higher value than 5V. And I have never seen an LED being damaged for that reason. So, I have been trying to figure why there is such an apparent huge discrepancy between what manufacturers recommend and what reality allows. In other words, why do manufacturers list 5V, when you can obviously go much higher, unlike most other absolute maximum ratings which have a much smaller safety margin. I have found a few hints, but nothing that definitely explains that difference. Does anyone know? and should that be mentioned in the article? Dhrm77 (talk) 12:35, 2 November 2023 (UTC)

I did used to drive them directly from 120VAC, but with a series silicon diode. I never tested them for PIV, though. If you have a current limited adjustable source, you can measure the reverse breakdown. Gah4 (talk) 00:14, 4 March 2024 (UTC)

I've read the 1961 Allen & Cherry paper cited in this article. The sentence claiming that this paper reports on light emission isn't correct - that paper mostly discusses photoconductivity. I'll delete the sentence in a day or so. It is possible that Allen & Cherry did observed light emission around then, but that important claim is not backed up by the reference. Easchiff (talk) 03:22, 8 January 2024 (UTC)

This paragraph of the article has been revised to expand on the GaAsP devices that were the first visible light LEDs to be commercialized. The full history of visible light LEDs is complex, and there is further discussion later in the article. Easchiff (talk) 15:43, 14 January 2024 (UTC)

This proposed wording would require much better sources to include. The term "inventors" is vague and can have many different meanings, so it's not necessarily obvious what is meant here; and "despite" carries a WP:SYNTHy connection to the award, as though it is somehow of great import that they were awarded it for efficient blue LEDs. Making that connection would require a source saying something roughly comparable. The article already notes the full history of the development of the blue LED, which makes clear what their contribution was; but highlighting this aspect with a "despite" and categorically declaring them to not be the inventors isn't appropriate without a secondary source. --Aquillion (talk) 13:51, 10 February 2024 (UTC)

What I've heard that Shuji Nakamura, Hiroshi Amano and Isamu Akasaki, were awarded the prize for the blue LED, not specificantly for the high brightness blue LED. and the information before the awards section, is enough to prove that the Nobel prize in physics 2014 was awarded to the wrong people. זור987 (talk) 14:05, 10 February 2024 (UTC)

That sounds like WP:RIGHTGREATWRONGS. We definitely can't say or imply that the award itself was awarded to the wrong people unless we have sources supporting that explicitly. Even if they did get it wrong, Wikipedia isn't the place to try and correct that; we're an encyclopedia, so we summarize what other sources say - trying to "prove it" yourself is WP:SYNTH / WP:OR. --Aquillion (talk) 14:47, 10 February 2024 (UTC)

There were, many years ago, experiments with SiC. It was extremely inefficient, so didn't count as an actual LED, at least not for commercial use. The efficient statement is important. That might compare to 0.01% efficient or so. Gah4 (talk) 00:17, 4 March 2024 (UTC)

A table is needed showing the emitted colour of an LED versus things such as typical voltage required, doping material used... 2001:8003:E40F:9601:4D90:A972:FCCB:FA19 (talk) 06:12, 3 March 2024 (UTC)

It mostly doesn't depend on the doping, but the actual semiconductor material. Often they are alloys, such as the early GaAsP, which is a crystal mixture of GaAs and GaP, and with gap somewhere in between. But yes, a table would be nice, at least for the common cases. Gah4 (talk) 00:19, 4 March 2024 (UTC)

This existed way back in the day ( like 10 to 15 years ago0 on this article. someone deleted it between now and then. I've gone back through the edit history and found it. i've restored it under "Colors and Materials". MercuryVapor (talk) 00:41, 20 September 2024 (UTC)

The table is in the "physics" article, too. Which one shall we keep? It can't be in both places as it will be inconsistent. Not the only place this happens on Wikipedai. but let's try anyway. --Wtshymanski (talk) 01:58, 21 September 2024 (UTC)

Honestly. I am of the opinion that it would be better off on this specific page. Considering I wasn't even aware of the "LED physics" page til it was mentioned here. Perhaps this basic table exist here. And then a more in-depth and deeply descriptive version can exist on the physics tab. I imagine most people would appreciate the broken down and listed out version existing here on the more "mainstream" page. 2601:401:8280:2150:359F:CCB0:DEFA:E116 (talk) 03:18, 21 September 2024 (UTC)

As well as I know it, if you want a consistent table then you make a template, and transclude it in all the articles. Only one place to get it right, or wrong. Gah4 (talk) 00:38, 24 September 2024 (UTC)

I cleaned up the section "Other white LEDs" by retitling it "Zinc selenide white LEDs" and shortening it to one brief paragraph. It was mostly just a summary of one paper and thus completely WP:UNDUE. If anyone has successfully commercialized ZnSe LEDs, that can always be added, but the paper was from 25 years ago so clearly this wasn't a transformative technology. Anyway, feel free to expand as long as you write it yourself. LLM template removed from this section. WeirdNAnnoyed (talk) 12:56, 14 September 2025 (UTC)