Photocurrent Spectroscopy of Perovskite Layers and Solar Cells: A Sensitive Probe of Material Degradation

Holovský, Jakub; De Wolf, Stefaan; Werner, Jérémie; Remeš, Zdeněk; Müller, Martin; Neykova, Neda; Ledinský, Martin; Černá, Ladislava; Hrzina, Pavel; Löper, Philipp; Niesen, Bjoern; Ballif, Christophe

Photocurrent Spectroscopy of Perovskite Layers and Solar Cells: A Sensitive Probe of Material Degradation

Type

Article

Authors

Holovský, Jakub
De Wolf, Stefaan

Werner, Jérémie
Remeš, Zdeněk
Müller, Martin
Neykova, Neda
Ledinský, Martin
Černá, Ladislava
Hrzina, Pavel
Löper, Philipp
Niesen, Bjoern
Ballif, Christophe

KAUST Department

KAUST Solar Center (KSC)
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division

Online Publication Date

2017-02-06

Print Publication Date

2017-02-16

Date

2017-02-06

Abstract

Optical absorptance spectroscopy of polycrystalline CHNHPbI films usually indicates the presence of a PbI phase, either as a preparation residue or due to film degradation, but gives no insight on how this may affect electrical properties. Here, we apply photocurrent spectroscopy to both perovskite solar cells and coplanar-contacted layers at various stages of degradation. In both cases, we find that the presence of a PbI phase restricts charge-carrier transport, suggesting that PbI encapsulates CHNHPbI grains. We also find that PbI injects holes into the CHNHPbI grains, increasing the apparent photosensitivity of PbI. This phenomenon, known as modulation doping, is absent in the photocurrent spectra of solar cells, where holes and electrons have to be collected in pairs. This interpretation provides insights into the photogeneration and carrier transport in dual-phase perovskites.

Citation

Holovský J, De Wolf S, Werner J, Remeš Z, Müller M, et al. (2017) Photocurrent Spectroscopy of Perovskite Layers and Solar Cells: A Sensitive Probe of Material Degradation. The Journal of Physical Chemistry Letters 8: 838–843. Available: http://dx.doi.org/10.1021/acs.jpclett.6b02854.

Acknowledgements

The authors acknowledge financial support from Czech Science Foundation Project No. 17-26041Y, the Project KONNECT- 007 of the Czech Academy of Sciences, the Czech Ministry of Education, Youth and Sports Projects LM2015087 and CZ.02.1.01/0.0/0.0/15_003/0000464 Centre of Advanced Photovoltaics, and the Swiss National Science Foundation through Nanotera and PNR 70 program. We thank Prof. Roman Grill and Dr. Thomas Dittrich for fruitful discussions.