The importance of oxygen exposure of perovskite solar cells with a PEDOT:PSS hole transport layer
Bardo Bruijnaers a, Eric Schiepers a, Christ Weijtens a, Stefan Meskers a, Martijn Wienk a, René Janssen a
a Molecular Materials and Nanosystems, Eindhoven University of Technology, Netherlands, Netherlands
International Conference on Hybrid and Organic Photovoltaics
Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV18)
Benidorm, Spain, 2018 May 28th - 31st
Organizers: Emilio Palomares and Rene Janssen
Oral, Bardo Bruijnaers, presentation 120
DOI: https://doi.org/10.29363/nanoge.hopv.2018.120
Publication date: 21st February 2018

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a frequently used as hole transport layer in planar p-i-n perovskite solar cells. We show that processing of a metal halide perovskite layer on top of PEDOT:PSS via spin coating of a precursor solution chemically reduces the oxidation state of PEDOT:PSS. The partial reduction of PEDOT:PSS from the highly oxidized bipolaron state to the polaron state, reduces the work function of the PEDOT:PSS whereby the work function becomes equal to the ionization potential. This reduction in the work function of the PEDOT:PSS also reduces the work function of the perovskite layer that is positioned on top of it. As a consequence, the solar cells display inferior performance with a reduced open-circuit voltage and a reduced short-circuit current density. Additionally, the increase of current density with light intensity becomes more sublinear. The reduced PEDOT:PSS can be (partially) re-oxidized even by short (8 min.) exposure to oxygen during thermal annealing of the PEDOT:PSS/perovskite layer stak, restoring its functionality in the solar cell. Therefore, annealing the PEDOT:PSS/Perovskite stack in the presence of oxygen results in solar cells with increased open-circuit voltage, short-circuit current density and high efficiency. Additionally, we show that the bulk properties of the perovskite layer do not change by annealing in different atmospheres.

© FUNDACIO DE LA COMUNITAT VALENCIANA SCITO
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info