Vacancy-Ordered Double Perovskite Cs2TeI6 Thin Films for Optoelectronics



Vazquez-Fernandez, Isabel, Mariotti, Silvia, Hutter, Oliver S, Birkett, Max, Veal, Tim D, Hobson, Theodore DC, Phillips, Laurie J, Danos, Lefteris, Nayak, Pabitra K, Snaith, Henry J
et al (show 4 more authors) (2020) Vacancy-Ordered Double Perovskite Cs2TeI6 Thin Films for Optoelectronics. Chemistry of Materials, 32 (15). pp. 6676-6684.

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Abstract

Alternatives to lead- and tin-based perovskites for photovoltaics and optoelectronics are sought that do not suffer from the disadvantages of toxicity and low device efficiency of present-day materials. Here we report a study of the double perovskite Cs<sub>2</sub>TeI<sub>6</sub>, which we have synthesized in the thin film form for the first time. Exhaustive trials concluded that spin coating CsI and TeI<sub>4</sub> using an antisolvent method produced uniform films, confirmed as Cs<sub>2</sub>TeI<sub>6</sub> by XRD with Rietveld analysis. They were stable up to 250 °C and had an optical band gap of ∼1.5 eV, absorption coefficients of ∼6 × 10<sup>4</sup> cm<sup>-1</sup>, carrier lifetimes of ∼2.6 ns (unpassivated 200 nm film), a work function of 4.95 eV, and a p-type surface conductivity. Vibrational modes probed by Raman and FTIR spectroscopy showed resonances qualitatively consistent with DFT <i>Phonopy</i>-calculated spectra, offering another route for phase confirmation. It was concluded that the material is a candidate for further study as a potential optoelectronic or photovoltaic material.

Item Type: Article
Uncontrolled Keywords: 3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 3406 Physical Chemistry, 7 Affordable and Clean Energy
Depositing User: Symplectic Admin
Date Deposited: 14 Jul 2020 10:01
Last Modified: 21 Jun 2024 00:48
DOI: 10.1021/acs.chemmater.0c02150
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3093535