1 cm2 CH3NH3PbI3 mesoporous solar cells with 17.8% steady-state efficiency by tailoring front FTO electrodes

Afzaal, M; Yates, HM; Walter, A; Nicolay, S; Ballif, C

Abstract

In this article, we investigate the effects of atmospheric-pressure chemical vapour deposited fluorine doped
tin oxide (FTO) thin films as front electrodes for the fabrication of mesoporous perovskite solar cells with an
active area of 1 cm2 and compare them with the use of a commonly used commercial transparent
conducting oxide. The effects of sheet resistance (Rs) and surface roughness are both closely linked to the
film thickness. In order to separate out these effects the characteristics of the deposited FTOs were carefully
controlled by changing the fluorine doping levels and the number of passes under the coating head to give
films of specific thicknesses or Rs. Under AM 1.5 Sun illumination and maximum power point tracking, the
optimised FTOs yielded a steady-state power conversion efficiency of 17.8%, higher than that of the
reference cell fabricated from the commercial FTO. We attribute the improved cell efficiency to increased
fill factor and a lower series resistance resulting from the lower Rs and increased thickness of these FTO
substrates. This low-cost and viable methodology is the first such type of study looking independently at the
significance of FTO roughness and resistance for highly efficient mesoporous perovskite solar cells.

• Journal Article Type: Article
• Acceptance Date: Apr 24, 2017
• Publication Date: May 12, 2017
• Deposit Date: Jun 5, 2017
• Publicly Available Date: May 12, 2018
• Journal: Journal of Materials Chemistry C
• Print ISSN: 2050-7526
• Publisher: Royal Society of Chemistry
• Volume: 5
• Issue: 20
• Pages: 4946-4950
• DOI: https://doi.org/10.1039/c7tc01248a
• Publisher URL: https://doi.org/10.1039/c7tc01248a
• Related Public URLs: http://pubs.rsc.org/en/journals/journalissues/tc#!recentarticles
• Additional Information: Projects : PLIANT