Influence of Fermi Level Alignment with Tin Oxide on the Hysteresis of Perovskite Solar Cells

Meltem F Aygüler; Alexander G Hufnagel; Philipp Rieder; Michael Wussler; Wolfram Jaegermann; Thomas Bein; Vladimir Dyakonov; Michiel L Petrus; Andreas Baumann; Pablo Docampo

doi:10.1021/acsami.8b00990

Influence of Fermi Level Alignment with Tin Oxide on the Hysteresis of Perovskite Solar Cells

ACS Appl Mater Interfaces. 2018 Apr 11;10(14):11414-11419. doi: 10.1021/acsami.8b00990. Epub 2018 Mar 28.

Authors

Affiliations

¹ Department of Chemistry and Center for NanoScience (CeNS) , LMU Munich , Butenandtstrasse 5-13 , 81377 München , Germany.
² Experimental Physics VI , Julius Maximilian University of Würzburg , 97074 Würzburg , Germany.
³ Materials Science Department , Technische Universität Darmstadt , Otto Berndt Strasse 3 , D-64287 Darmstadt , Germany.
⁴ Bavarian Center for Applied Energy Research (ZAE Bayern) , 97074 Würzburg , Germany.
⁵ Physics Department, School of Electrical and Electronic Engineering , Newcastle University , Newcastle upon Tyne NE1 7RU , United Kingdom.

PMID: 29557162
DOI: 10.1021/acsami.8b00990

Abstract

We tune the Fermi level alignment between the SnO _x electron transport layer (ETL) and Cs_0.05(FA_0.83MA_0.17)_0.95Pb(I_0.83Br_0.17)₃ and highlight that this parameter is interlinked with current-voltage hysteresis in perovskite solar cells (PSCs). Furthermore, thermally stimulated current measurements reveal that the depth of trap states in the ETL or at the ETL-perovskite interface correlates with Fermi level positions, ultimately linking it to the energy difference between the Fermi level and conduction band minimum. In the presence of deep trap states, charge accumulation and recombination at the interface are promoted, affecting the charge collection efficiency adversely, which increases the hysteresis of PSCs.

Keywords: Fermi level alignment; hysteresis; perovskite solar cells; perovskite-contact interface; tin oxide; trap depth energy.