Ukrainian Journal of Physical Optics

2022, Volume 23, Issue 3

ISSN 1816-2002 (Online), ISSN 1609-1833 (Print)

Pre-themalizational effect of hot carriers on photovoltage formation in a solar cell

Masalskyi O., Gradauskas J.

Vilnius Gediminas Technical University, Saulėtekio Avenue 11, 10223 Vilnius, Lithuania;


Although the power-conversion efficiency of single-junction solar cells achieved in practice is slowly increasing in the recent years, it still remains well below the theoretical Shockley–Queisser limit. We analyze in this relation the impact of hot carriers which represents an additional fundamental mechanism of intrinsic losses. We suggest that it is one of the reasons why the theoretical efficiency limit cannot be reached. We demonstrate that all of the solar photons participate in carrier heating, except for those having the energy equal to the bandgap. This supplies the process with more than 52% of the total incident solar energy. Finally, we give experimental evidence to a hot-carrier photovoltage (PV) arising in Si and GaAs cells before thermalization process. This PV is opposite to a classical PV induced by carrier generation, thus hindering the efficiency of p-n-junction solar cells.

solar cells, p-n junctions, photovoltage, hot carriers, efficiency

UDC: 535.215

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    Практично досягнута ефективність перетворення енергії одноперехідного сонячного елемента все ще значно нижча від теоретичної межі Шоклі-Квайссера і зростає дуже повільно з наступними роками. Ми вводимо явище гарячих носіїв як додатковий фундаментальний механізм власних втрат, який, як передбачається, відповідає за практичну недосяжність теоретичної межі ефективності. Всі сонячні фотони, крім тих, енергія яких дорівнює ширині забороненої зони напівпровідника, беруть участь у нагріванні носіїв і забезпечують цей процес більш ніж 52% всієї сонячної енергії. Ми також показуємо експериментальні доводи фотонапруги (ФН) гарячих носіїв у елементах з Si та GaAs яка зростає ще до процесу термалізації. Ця ФН протидіє класичній фотонапрузі, викликаній генерацією носіїв, та таким чином наноситься безпосередня втрата ефективності сонячного елемента з p-n переходом.

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