Talk:Quantum dot

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Former good article nominee Quantum dot was a good articles nominee, but did not meet the good article criteria at the time. There are suggestions below for improving the article. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.
April 12, 2006 Good article nominee Not listed
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What?[edit]

"Stated simply, quantum dots are semiconductors whose electronic characteristics are closely related to the size and shape of the individual crystal." "the" crystal? Which crystal? What electronic properties does the size or shape of "the" crystal impart? Since when are crystals confined to a specific size? There's a cave in Mexico with crystals the size of a bus, could those be quantum dots too? This makes no sense. There's nothing simple about this statement at all. --MoonLichen (talk) 03:51, 24 February 2011 (UTC)

Use of "zero dimensional"[edit]

I think that needs to be qualified in some sense, since the dots themselves are obvious not zero dimensional. Perhaps state that "their unique behavior is due (in part) to the relatively small number of atoms they are composed of, and can be explained with models that treat them as zero dimensional". I'm not sure if this proposed statement is actually correct. Maneesh (talk) 16:58, 22 April 2011 (UTC)

Zero-dimensional is merely a reference to the number of directions in which the confined charge carrier can act as a free carrier. In a similar vein, quantum wires might be known as one-dimensional potential wells, and quantum wells as two-dimensional potential wells. I'm currently looking for a good place to put this but can't decide where would be best.
While the dots/wires/wells are small, they still have dimensions in the nm range - indeed it's hinted at in the introduction and stated explicitly in the production section. --  Newty  14:04, 23 October 2011 (UTC)

Developments concerning bulk manufacture[edit]

I've added a section in the main article concerning the bulk manufacture of quantum dots. For transparency: I am affiliated with one companies involved, this I've added to my edit in the history section as well. I've tried to strike a tone as neutral as possible in my contribution, including a reference to a press release and an article about current prospects of quantum dots from The Economist. There is as yet no independent news article using the press release as a source. If so, it should replace the original press release as a source. If there are any thoughts, additions or objections please discuss them here in this section. — Preceding unsigned comment added by 85.223.101.162 (talk) 14:51, 7 July 2011 (UTC)

now can be dissolved in water[edit]

'The researchers therefore developed an amphiphilic coating, i.e. one with both hydrophobic and hydrophilic properties. The "water hating" side of the polymer material attaches to the surface of the quantum dot. Its exposed hydrophilic side then makes the quantum dot/coating combination soluble in water'

http://www.sciencedaily.com/releases/2011/10/111026091008.htm — Preceding unsigned comment added by 75.85.14.106 (talk) 05:53, 29 October 2011 (UTC)

"experimental proof" vs. controversial[edit]

"According to an experimental proof from 2006 (controversial results[33])," How does that sentence make sense? — Preceding unsigned comment added by 109.193.165.35 (talk) 19:53, 31 January 2012 (UTC)

Mistake in Quantum Confinement[edit]

"since no two nearby electrons can share the exact same energy level according to Pauli exclusion principle"

I have never heard of this interpretation of Pauli's exclusion principle. If this were true, the term "degeneracy" wouldn't exist. Pauli exclusion only says, that they cannot exist in the very same quantum state. They have to be distinguishable, but not necessarily in energy.

Gflaesch (talk) 21:53, 4 February 2012 (UTC)

That whole paragraph is unclear and poorly written. By all means, feel free to be bold and fix it up yourself! If you have any questions about editing I'm happy to try and answer them. Antony–22 (talkcontribs) 17:49, 5 February 2012 (UTC)

Confinement Energy[edit]

I am pretty sure that the equations for the confinement energy should contain the "effective electron mass" and the "effective hole mass" and not the "free electron mass" and the "hole mass" (while "free electron mass" is definetly wrong, "hole mass" might not be all that bad since there is no such thing as a free hole mass and thus in cannot be misinterpreted...) — Preceding unsigned comment added by 130.75.157.49 (talk) 16:50, 3 December 2012 (UTC)

Possible inaccuracy in an illustration title[edit]

The figure titled "Quantum Dots with emission maxima in a 10-nm step are being produced in a kg scale at PlasmaChem GmbH" displays QD solutions producing luminescence from violet (470 nm) to orange (610 nm) and thus has an inaccurate title. However, WikiCommons provides correct description as follows "Quantum dots with vivid colours stretching from violet to deep red are being currently manufactured at PlasmaChem GmbH at a large scale". The manufacturer data sheet for whole QD kit validates this. I suppose a new title "Quantum Dots with gradually stepping emission from violet to deep red are being produced in a kg scale at PlasmaChem GmbH" Hardman Feidlimid (talk) 21:42, 31 October 2013 (UTC)

Be bold: if you see a mistake like this, click "Edit" and change the text so that it is more accurate. KDS4444Talk 11:15, 29 January 2014 (UTC)

Primary sources are overused in this article[edit]

The intro paragraph to this article has at least three references (enclosed in "ref" tags) that point to the primary source of the information they are referencing— this is not the way that citations are supposed to be used in Wikipedia. Citations should point to the place where the statement of fact is published or discussed, not to where the actual information itself is published. For example, when I write in an article "John Smith discovered gravity" and I provide a reference for that fact, the reference should point to a source, normally a third party, stating that John Smith did, in fact, discovered gravity, NOT to John Smith's journal article or the book he wrote in which he explained all about the nature of gravity. References should point to where the statement of fact is verified, not to the place where the fact itself is discovered nor where it was first stated. I know that may seem confusing, but if you can figure out quantum physics then this can't be much harder to grasp! KDS4444Talk 11:09, 29 January 2014 (UTC)

This is a good point. In this particular page, the ref to Reed et al, 1988, as the "primary" source of the phrase "quantum dots" is actually superceed by a previous paper on which Mark is the lead author: Reed et al. J. Vac. Sci. Technol. B 4(1), Jan/Feb 1986 pp. 358-360. In fact, without actually having gone through the entire set of literature, I'm more confident that this 1986 paper is more believable as the most-extant use of this phrase given that the phrasing in this paper is: "Here we present data on a completely spatially quantized system (which by extrapolation we define as 'quantum dots') where ...". Indeed, the author explicitly notes that it is "defined" here. On the other hand, the paper cited on the present page is merely a parenthetical note in the abstract: "('quantum dot')". TJ LaFave (talk) 01:25, 12 February 2014 (UTC)
I further agree that citing the most-extant (or "primary" source) is not a sufficient proof of the claim mentioned. I haven't looked closer at the other citations in the introductory paragraph, however, if references 1-3 are of issue, I think the sentence is found in various forms elsewhere on the web, but with different cited sources! E.g. Sigma Aldrich's page on quantum dots. (Apologies if my signature here doesn't work. I don't interact with Wikipedia much -- yet.) TJ LaFave (talk) 01:25, 12 February 2014 (UTC)

Intro paragraphs needs work, operating principle unclear[edit]

The introduction says that quantum dots are nanocrystals made of semiconductors, but doesn't explain what useful features they have. Numerous applications are mentioned, but it remains obscure what the underlying principle is. The first sentence of the third paragraph mentions "emitted light" in passing. Is that the point of quantum dots, that they emits light? Under what conditions will they emit light? Are there other use cases besides emitting light? AxelBoldt (talk) 02:08, 28 November 2014 (UTC)

Proposed merge with Artificial atom[edit]

The only known examples of artificial atoms are quantum dots. Llightex (talk) 20:57, 31 March 2015 (UTC) Yes check.svg Done

Statement about quantum confinement in the sun is unclear and unsupported by references[edit]

In the section "Band cap energy" is a sentence ending:

"which is precisely what happens in the sun, where the quantum confinement effects are completely dominant and the energy levels split up to the degree that the energy spectrum is almost continuous, thus emitting white light."

to which I added a "Citation required" note. "in the sun" is not specific enough. Perhaps "in the photosphere of the sun" might be better. If a statement such as this remains in the article, I think it should be more self-explanatory, perhaps have its own section (if it is relevant to quantum dots directly - otherwise it should be somewhere else) and should cite references. A quick Google for sun and "quantum confinement" didn't produce anything which seemed relevant. — Preceding unsigned comment added by Robin Whittle (talkcontribs) 10:20, 19 April 2015 (UTC)

Large literature on quantum dots[edit]

According to Chemical Abstracts today, here are some figures: 73443 papers, patents, whatever refer to quantum dots 52226 have appeared in the past 10 years 2286 of these recent articles are classified as reviews Conclusions: the literature is so massive we really need to not only stick to secondary sources, and even then the situation is almost impossible.--Smokefoot (talk) 00:33, 6 June 2016 (UTC)