In DepthMaterials Science

Perovskite LEDs begin to shine

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Science  07 Jun 2019:
Vol. 364, Issue 6444, pp. 918
DOI: 10.1126/science.364.6444.918

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  • RE: Conservation laws:

    Conservation laws:

    6/10/19

    A brief comment about respecting the laws of conservation.

    Recently I read an interesting short article on new LED materials [Service R.F- 2019-Perovskite LEDs begin to shine- Science 364: (#6444, 6/7) 918]. While the information in the article was interesting, there was one aspect of it which caught my attention. This relates to the following two statements:

    “Now, perovskites are turning the tables, converting electrons into light with an efficiency on par with that of the commercial organic light-emitting diodes (LEDs) found in cellphones and flat screen TVs.” pg. 918
    “The earliest perovskite LEDs converted only 0.76% of electrons into photons.” pg. 918

    The issue which caught my attention is the suggestion that electons are being “converted” into light.

    Electrons have two features which photons lack: mass and charge. So if electrons are truly being “converted” into photons, then mass and charge are both being lost; a violation of the laws of conservation of mass and charge. And if the mass of the electron is being “converted” into energy, then either this is a violation of the conservation of energy (as new energy would be formed), or the implication is that somehow this material is engaging in E = mc2 type conversions? While that might be valid for nuclear reactors, or for solar physics, I do not believe that solar panel materials engage in such conversions.

    Thus the phrasi...

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    Competing Interests: None declared.
  • Low-cost duality devices will play a key role in incubating new applications

    Robert F. Service wrote an article entitled “Perovskite LEDs begin to shine” (1). A solar cell not only generates electricity but also emits light. As far as we know, duality of physical phenomena can be simply observed in many devices (2). Peltier devices have been used for cooling and heating. Providing the temperature difference between two sides of a Peltier device can generate electric power which is called Seebeck effect. We have tested solar cells to generate electricity and to remove snow on the roof by generated heat. Current LEDs (Light Emitting Diodes) can be used as sensors or cameras. The physical phenomena or their components always have duality. According to the latest technology, infrared emitting device functions energy harvesting (3). The researchers of duality devices need not only to improve the energy conversion efficiency between emitted light and generated electricity, but also to expand the life of the components. They should also reduce manufacturing cost as much as possible for incubating real new applications.

    References:
    1. Robert F. Service, Perovskite LEDs begin to shine, Science 07 Jun 2019: Vol. 364, Issue 6444, pp. 918
    2. https://science.sciencemag.org/content/362/6410/35/tab-e-letters
    3.https://phys.org/news/2017-04-infrared-emitting-device-energy-ha...

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    Competing Interests: None declared.