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Nanowire Solar Cell Above the Radiative Limit
Author(s) -
Korzun Ksenia,
Castellanos Gabriel W.,
Boer Dick K. G.,
Gómez Rivas Jaime,
Haverkort Jos E. M.
Publication year - 2021
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202001636
Subject(s) - nanowire , materials science , optics , solar cell , solid angle , radiative transfer , photon , optoelectronics , light emission , spontaneous emission , physics , laser , detector
A lossless solar cell operating at the Shockley–Queisser limit generates an open circuit voltage ( V oc ) equal to the radiative limit. At V oc , the highly directional beam of photons from the sun is absorbed and subsequently externally re‐emitted into a 4π solid angle, providing a large photon entropy loss. A solar cell can beat the Shockley–Queisser limit and approach the 46.7% ultimate limit by decreasing the output solid angle of the light emission at open circuit conditions. Here, a design for an indium phosphide single nanowire solar cell capable to operate 159 mV above the radiative limit is presented. The spontaneous emission factor is first optimized into a guided mode of the nanowire toward 68%. The authors subsequently launch a guided mode at the bottom straight part of the tapered nanowire yielding a photon escape probability of 81% for a tapering angle of θ = 1.2° and a top facet with a radius of 83 nm. When assuming homogeneous light emission along the nanowire, an outcoupling efficiency of 42% of the emitted light is obtained. The final optimization is the reduction of the emission cone toward 11 × 10 −3 sr by focusing the guided mode with an external lens.