TY - JOUR
T1 - Tailored emission to boost open-circuit voltage in solar cells
AU - Anttu, Nicklas
AU - Kivisaari, Pyry
AU - Chen, Yang
N1 - Publisher Copyright:
© 2019 The Author(s). Published by IOP Publishing Ltd.
PY - 2019/5
Y1 - 2019/5
N2 - Recently, a lot of research focus has been on how to make solar cells more efficient. One direction is to enhance the open-circuit voltage Voc by optimizing the emission of photons in the cell, where emission is a necessary loss process due to the reciprocity between absorption and emission of light. Here, we performed a Shockley-Queisser detailed balance analysis to predict the benefit of managing emitted photons in a single-junction solar cell. First, at low internal luminescence efficiency ηint, non-radiative recombination dominates, and management of emitted photons plays negligible role for Voc . Similarly, for an external luminescence efficiency ηext<10%, externally emitted photons play negligible role, and Voc is set either by non-radiative recombination; or parasitic absorption of internally emitted photons. For higher ηext, the Voc can be boosted, maximally by 15%, by restricting the external emission to match the incidence cone of the AM1.5D sun light spectrum. Such emission restriction corresponds to lower escape probability of internally emitted photons, enhances photon recycling, drops ηext, and actually makes the solar cell into a worse LED. Finally, for partly diffuse incident light, by restricting the angular emission for photons in a 130 nm wavelength range around the bandgap, we predict a maximum 14% relative boost in solar cell efficiency. The results of this paper are intended to serve as a general guideline on how to utilize emission-tuning possibilities to develop highly efficient photovoltaic devices.
AB - Recently, a lot of research focus has been on how to make solar cells more efficient. One direction is to enhance the open-circuit voltage Voc by optimizing the emission of photons in the cell, where emission is a necessary loss process due to the reciprocity between absorption and emission of light. Here, we performed a Shockley-Queisser detailed balance analysis to predict the benefit of managing emitted photons in a single-junction solar cell. First, at low internal luminescence efficiency ηint, non-radiative recombination dominates, and management of emitted photons plays negligible role for Voc . Similarly, for an external luminescence efficiency ηext<10%, externally emitted photons play negligible role, and Voc is set either by non-radiative recombination; or parasitic absorption of internally emitted photons. For higher ηext, the Voc can be boosted, maximally by 15%, by restricting the external emission to match the incidence cone of the AM1.5D sun light spectrum. Such emission restriction corresponds to lower escape probability of internally emitted photons, enhances photon recycling, drops ηext, and actually makes the solar cell into a worse LED. Finally, for partly diffuse incident light, by restricting the angular emission for photons in a 130 nm wavelength range around the bandgap, we predict a maximum 14% relative boost in solar cell efficiency. The results of this paper are intended to serve as a general guideline on how to utilize emission-tuning possibilities to develop highly efficient photovoltaic devices.
KW - Emisison management
KW - Open-circuit voltage
KW - Solar cell
UR - http://www.scopus.com/inward/record.url?scp=85078295462&partnerID=8YFLogxK
U2 - 10.1088/2399-6528/ab1cc4
DO - 10.1088/2399-6528/ab1cc4
M3 - Article
AN - SCOPUS:85078295462
SN - 2399-6528
VL - 3
JO - Journal of Physics Communications
JF - Journal of Physics Communications
IS - 5
M1 - 055009
ER -