Passivation and carrier selectivity of TiO2 contacts combined with different passivation layers and electrodes for silicon solar cells

Mathieu Boccard, Xinbo Yang, Klaus Weber, Zachary Holman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Titanium dioxide (TiO2) films have previously been demonstrated to function as electron-selective contacts to silicon solar cells, and an efficiency of 21.6% has been reported for a cell featuring a full-area TiO2 contact. However, the passivation quality of TiO2 contacts still falls short of that possible with best-in-class contacts based on, e.g., hydrogenated amorphous silicon (a-Si:H). We investigate here the performance of a-Si:H/TiO2 stacks as electron-selective, passivating contacts. We show that combining a-Si:H with TiO2 can result in excellent surface passivation (lifetime close to 3 ms for textured CZ wafers), especially for 7.5-nm-thick TiO2 capping layers. However, initial cell results show that such a-Si:H/TiO2 stacks give poorer efficiencies than TiO2 only, with extremely low fill factors due to S-shaped current-voltage curves. Also, the role of the rear electrode becomes apparent when substituting Al for an ITO/Ag stack: the latter has significantly lower open-circuit voltage and fill factor than the former. Combining a TiO2/Al rear electron contact (with no a-Si:H) and an intrinsic a-Si:H/p-type a-Si:H front hole contact, we demonstrate a double heterojunction silicon solar cell with an efficiency of approximately 15%. Furthermore, a full metal-oxide heterojunction cell that combines a molybdenum oxide (MoOx)/ITO hole contact with the TiO2/Al electron contact achieves an efficiency of 11%.

Original languageEnglish (US)
Title of host publication2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages1-5
Number of pages5
ISBN (Electronic)9781509056057
DOIs
StatePublished - May 25 2018
Event44th IEEE Photovoltaic Specialist Conference, PVSC 2017 - Washington, United States
Duration: Jun 25 2017Jun 30 2017

Other

Other44th IEEE Photovoltaic Specialist Conference, PVSC 2017
CountryUnited States
CityWashington
Period6/25/176/30/17

Fingerprint

Silicon solar cells
Passivation
Electrodes
Electrons
Heterojunctions
Molybdenum oxide
Open circuit voltage
Amorphous silicon
Titanium dioxide
Oxides
Metals
Electric potential

Keywords

  • Carrier-selective contact
  • Crystalline silicon solar cell
  • Electrode
  • Passivation
  • TiO

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials

Cite this

Boccard, M., Yang, X., Weber, K., & Holman, Z. (2018). Passivation and carrier selectivity of TiO2 contacts combined with different passivation layers and electrodes for silicon solar cells. In 2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017 (pp. 1-5). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/PVSC.2017.8366554

Passivation and carrier selectivity of TiO2 contacts combined with different passivation layers and electrodes for silicon solar cells. / Boccard, Mathieu; Yang, Xinbo; Weber, Klaus; Holman, Zachary.

2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017. Institute of Electrical and Electronics Engineers Inc., 2018. p. 1-5.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Boccard, M, Yang, X, Weber, K & Holman, Z 2018, Passivation and carrier selectivity of TiO2 contacts combined with different passivation layers and electrodes for silicon solar cells. in 2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017. Institute of Electrical and Electronics Engineers Inc., pp. 1-5, 44th IEEE Photovoltaic Specialist Conference, PVSC 2017, Washington, United States, 6/25/17. https://doi.org/10.1109/PVSC.2017.8366554
Boccard M, Yang X, Weber K, Holman Z. Passivation and carrier selectivity of TiO2 contacts combined with different passivation layers and electrodes for silicon solar cells. In 2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017. Institute of Electrical and Electronics Engineers Inc. 2018. p. 1-5 https://doi.org/10.1109/PVSC.2017.8366554
Boccard, Mathieu ; Yang, Xinbo ; Weber, Klaus ; Holman, Zachary. / Passivation and carrier selectivity of TiO2 contacts combined with different passivation layers and electrodes for silicon solar cells. 2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017. Institute of Electrical and Electronics Engineers Inc., 2018. pp. 1-5
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