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I came across with the article on a russian website, saying they are planning to start production of solar cells using advanced semiconductor technology called "quantum heterostructure" (maybe in other words heterojunction?), allowing to increase efficiency twice at the same time reducing the production costs by almost four times.

I am not involved in semiconductor technologies, but as far as I know, this technology as a photovoltaic application (multi-junction solar cell) is used in NASA's Mars Exploration Rover mission and back in days was (actually first time) used by Soviet space mission (I do not remember which). But it was not feasible for mass production in utility scale. But maybe I am not enough informed.

Is something like that already possible? If yes, how they could do it?

P.S. I am still trying to understand what is behind this technology. If I find more info about this I will share here.

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  • $\begingroup$ Space mission typically use dual or triple junction cells. These are basically just two or three solar cells made from different semiconducting materials on top of each other. Using different bandgaps a dual junction or triple junction cell can use photons of different energy more efficiently. Short wavelengths can be absorbed in the material with the larger bandgap, causing a higher voltage, while long wavelengths are adding a lower voltage in the layer with the smaller bandgap. These cells have been available for decades, they are normally just too expensive to be competitive. $\endgroup$ – CuriousOne Feb 23 '16 at 9:49
  • $\begingroup$ See e.g. en.wikipedia.org/wiki/Multi-junction_solar_cell $\endgroup$ – CuriousOne Feb 23 '16 at 9:50
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Every few months, we get a new press release about quantum heterostructures - such as quantum dots - for PV. The story is always the same: this time it's cheap, efficient and scalable.

After a decade or so of this, we've yet to see any one of them become cheap, efficient and scalable.

This has also been true of complex heterojunctions too: multiple semiconductors with different bandgaps, overlaid to try to harvest more energy.

The physics ought to be fairly straightforward: different bandgaps should mean more efficient harvesting of the big spread of frequencies that daylight comes in. But the issue is engineering and economics: fabrication requires more complex processes, and the consequences of that is that this way of producing high-efficiency long-life cells is more expensive per unit of delivered electricity, so not a commercial proposition.

Meanwhile, the altogether less exciting normal PV, whether silicon or cadmium telluride, just keep getting cheaper, more efficient and more scalable.

So, heterostructures and heterojunctions may have niche applications - such as space exploration, where power per unit weight is what counts. But for mass use (and at time of writing, global manufacturing and installation of PV is about a us$100bn/year industry), these press releases have no real-world significance: they're usually just someone hawking around for venture capital. And you won't find the interesting physics or engineering in these articles either - that's happening in the journal papers that come out of the labs.

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