26.1%-efficient POLO-IBC cells

Quantification of electrical and optical loss mechanisms

verfasst von

Christina Hollemann, Felix Haase, Sören Schäfer, Jan Krügener, Rolf Brendel, Robby Peibst

Abstract

We present experimental results for interdigitated back contacted (IBC) solar cells with passivating POLO contacts for both polarities with a nominal intrinsic poly-Si region between them. We reach efficiencies of 26.1% and 24.9% on a 1.3 Ω cm and 80 Ω cm p-type FZ wafer and 24.6% on a 2 Ω cm n-type Cz wafer, respectively. The initially measured implied efficiency potentials of the cells after passivating the surfaces are very similar, namely, 26.8%, 26.8%, and 26.4%, respectively. We attribute the difference between the efficiency potential and the final current-voltage measurement to degradation, perimeter, and series and shunt resistance losses, which we quantify by lifetime measurements. With these measurements in combination with a finite element simulation, we determine the surface recombination velocity in the nominal intrinsic poly-Si region to be in the range from 13 to 21 cm s⁻¹. Using the same approach, we analyze the increase of the front surface recombination velocity during cell processing from 2 to 10 cm s⁻¹ for the 1.3 Ω cm and from 0.5 to 2.3 cm s⁻¹ for the 80 Ω cm. This leads to the fact that cells fabricated on lowly doped bulk material are more vulnerable to a process-induced degradation of the surface passivation quality. We further determine the theoretical limits of the cells by firstly idealizing the recombination (28% for 1.3 Ω cm and 28.2% for 80 Ω cm) and secondly also idealizing the optics of the solar cells (29.4% and 29.5%).

Organisationseinheit(en)

Institut für Materialien und Bauelemente der Elektronik
Laboratorium für Nano- und Quantenengineering
Abt. Solarenergie

Externe Organisation(en)

Institut für Solarenergieforschung GmbH (ISFH)

Typ

Artikel

Journal

Progress in Photovoltaics: Research and Applications

Band

27

Seiten

950-958

Anzahl der Seiten

9

ISSN

1062-7995

Publikationsdatum

01.11.2019

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Elektronische, optische und magnetische Materialien, Erneuerbare Energien, Nachhaltigkeit und Umwelt, Physik der kondensierten Materie, Elektrotechnik und Elektronik

Ziele für nachhaltige Entwicklung

SDG 7 – Erschwingliche und saubere Energie

Elektronische Version(en)

https://doi.org/10.1002/pip.3098 (Zugang: Geschlossen)