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The Shockley–Queisser limit, zoomed in near the region of peak efficiency. In a traditional solid-state semiconductor such as silicon, a solar cell is made from two doped crystals, one an n-type semiconductor, which has extra free electrons, and the other a p-type semiconductor, which is lacking free electrons, referred to as "holes."
They measured devices 100 million times smaller than that, with no mask. Not to mention, their efficiency calculation procedure involved multiplying the measured efficiency by a dubious factor of 30 (dubious because the 97% of light absorbed in ITO can also contribute to current, among other things).
The Shockley–Queisser limit for the efficiency of a single-junction solar cell under unconcentrated sunlight at 273 K. This calculated curve uses actual solar spectrum data, and therefore the curve is wiggly from IR absorption bands in the atmosphere. This efficiency limit of ~34% can be exceeded by multijunction solar cells.
Third-generation photovoltaic cells are solar cells that are potentially able to overcome the Shockley–Queisser limit of 31–41% power efficiency for single bandgap solar cells. This includes a range of alternatives to cells made of semiconducting p-n junctions ("first generation") and thin film cells ("second generation").
Some third-generation solar cells boost efficiency through the integration of concentrator and/or multi-junction device geometry. [63] This can lead to efficiencies larger than the Shockley–Queisser limit of approximately 42% efficiency for a single-junction semiconductor solar cell under one-sun illumination. [86]
However, the current graphical QE analysis still cannot reflect the second intrinsic loss in the efficiency of solar cells, radiative recombination. To take the radiative recombination into account, we need to evaluate the radiative current density, J rad, first. According to Shockley and Queisser method, [29] J rad can be approximated as follows.
The Shockley–Queisser limit radiative efficiency limit, also known as the detailed balance limit, [105] [106] is about 31% under an AM1.5G solar spectrum at 1000 W/m 2, for a Perovskite bandgap of 1.55 eV. [107] This is slightly smaller than the radiative limit of gallium arsenide of bandgap 1.42 eV which can reach a radiative efficiency of 33%.
The band gap (1.34 eV) of an ideal single-junction cell is close to that of silicon (1.1 eV), one of the many reasons that silicon dominates the market. However, silicon's efficiency is limited to about 30% (Shockley–Queisser limit). It is possible to improve on a single-junction cell by vertically stacking cells with different bandgaps ...