Return of incandescent light bulbs as MIT makes them more efficient than LEDs
This news article doesn&#x27;t even mention the article&#x27;s name, the authors, or when it was published.<p>It was actually published in January, and has just now been picked up by the Telegraph.<p>Here is the citation:<p><pre><code>    Ognjen Ilic, Peter Bermel, Gang Chen, John D. Joannopoulos, Ivan   
    Celanovic, Marin Soljačić. Tailoring high-temperature radiation and
    the resurrection of the incandescent source. Nature Nanotechnology,
    2016; DOI: 10.1038&#x2F;nnano.2015.309                                  
</code></pre>
And here is the actual paper, via Sci-Hub: <a href="http:&#x2F;&#x2F;sci-hub.cc&#x2F;10.1038&#x2F;nnano.2015.309" rel="nofollow">http:&#x2F;&#x2F;sci-hub.cc&#x2F;10.1038&#x2F;nnano.2015.309</a><p>The Telegraph&#x27;s explanation is terrible: &quot;with a special crystal structure in the glass they can bounce back the energy which is usually lost in heat, while still allowing the light through.&quot;<p>The tungsten filament is sandwiched between two plates made up of layers of oxides, designed to selectively reflect infrared radiation and transmit visible light.<p>They used a numerical model to design and evaluate various candidate compositions for these plates. For a proof-of-concept, they chose one which uses layers of silicon oxide and tantalum oxide, with 90 layers in total per plate. This reflected about 90% of infrared radiation, producing a luminous efficiency of about 6.6%. This is comparable to commercial LEDs and compact fluorescents, though far from state-of-the-art.<p>However, the results closely matched their numerical model, and a more complex structure comprised of layers of silicon dioxide, aluminium oxide, tantalum oxide and titanium dioxide, with 300 layers in total, should produce a luminous efficiency of 40%. This is significantly better than the state-of-the-art in LEDs (about 15-30%). They did not, however, actually build that one.<p>I have no idea how expensive this would be to commercialise. It doesn&#x27;t sound like the physics is particularly complex, but manufacturing costs could be prohibitive. I think it&#x27;s safe to say we won&#x27;t be seeing it outside the laboratory any time soon.