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Unravelling Defect Passivation Mechanisms in Sulfur-treated Sb2Se3

preprint
submitted on 16.02.2021, 09:57 and posted on 17.02.2021, 05:13 by Rajiv Ramanujam Prabhakar, Thomas Moehl, Dennis Friedrich, Marinus Kunst, Sudhanshu Shukla, Damilola Adeleye, Vinayaka H. Damle, Sebastian Siol, Wei Cui, Laxman Gouda, Jihye Suh, Yaakov R. Tischler, Roel van de Krol, David Tilley

Sb2Se3 has emerged as an important photoelectrochemical (PEC) and photovoltaic (PV) material due to its rapid rise in photoconversion efficiencies. However, despite its binary nature, Sb2Se3 has a complex defect chemistry, which reduces the maximum photovoltage that can be obtained. Thus, it is important to understand these defects and to develop passivation strategies in order to further improve this material. In this work, a comprehensive investigation of the charge carrier dynamics of Sb2Se3 and the influence of sulfur treatment on its optoelectronic properties was performed using time resolved microwave conductivity (TRMC), photoluminescence (PL) spectroscopy and low frequency Raman spectroscopy (LFRS). The key finding in this work is that upon sulfur treatment of Sb2Se3, the carrier lifetime is increased by the passivation of deep defects in Sb2Se3 in both the surface region and the bulk, which is evidenced by increased charge carrier lifetime of TRMC decay dynamics, increased radiative recombination efficiency and decreased deep defect level emission (PL), and improved long-range order in the material (LFRS). These findings provide crucial insights into the defect passivation mechanisms in Sb2Se3 paving the way for developing highly efficient PEC and PV devices.

History

Email Address of Submitting Author

david.tilley@chem.uzh.ch

Institution

University of Zurich

Country

Switzerland

ORCID For Submitting Author

0000-0002-7542-1147

Declaration of Conflict of Interest

None.

Licence

Exports