A Facile Aqueous Solution Route for the Growth of Chalcogenide Perovskite BaZrS3 Films

Abstract

The prototypical chalcogenide perovskite, BaZrS3 (BZS), with its direct bandgap of 1.7–1.8 eV, high chemical stability, and strong light–matter interactions, has garnered significant interest over the past few years. So far, attempts to grow BaZrS3 films have been limited mainly to physical vapor deposition techniques. Here, we report the fabrication of BZS thin films via a facile aqueous solution route of polymer-assisted deposition (PAD), where the polymer-chelated cation precursor films were sulfurized in a mixed CS2 and Ar atmosphere. The formation of a single-phase polycrystalline BZS thin film at a processing temperature of 900 °C was confirmed by X-ray diffraction and Raman spectroscopy. The stoichiometry of the films was verified by Rutherford Backscattering spectrometry and energy-dispersive X-ray spectroscopy. The BZS films showed a photoluminescence peak at around 1.8 eV and exhibited a photogenerated current under light illumination at a wavelength of 530 nm. Temperature-dependent resistivity analysis revealed that the conduction of BaZrS3 films under the dark condition could be described by the Efros–Shklovskii variable range hopping model in the temperature range of 60–300 K, with an activation energy of about 44 meV.

Chalcogenide Perovskite, An Emerging Photovoltaic Material: Current Status and Future Perspectives

“…Processing of thin film devices is not compatible at high temperature. So far only BaZrS 3 , [24,93,[108][109] LaYS 3 , [12,96] BaHfS 3 [110] and CaSnS 3 [111] have been realized in thin film form. New techniques such as solution processed moderate temperature synthesis using a single phase molecular precursor, [110,112] liquid flux assisted mechanism, [113] colloidal nanoscale synthesis, [114][115][116] molecular beam epitaxy [117] and post processing techniques need to be explored more for synthesis of chalcogenide perovskite.…”

Photoconductive Effects in Single Crystals of BaZrS3

“…■ RESULTS AND DISCUSSION Crystal Growth and Contact Fabrication. Single crystals of BaZrS 3 were grown in an evacuated sealed ampoule using BaCl 2 flux, as reported earlier 21,22 (Methods Section). We were able to achieve relatively larger single crystals of BaZrS 3 using the slower cooling rate (i.e., cubes with sides of ∼250 μm).…”

“…Polycrystalline − and epitaxial , thin films of BaZrS 3 have been used to realize prototypical metal–semiconductor heterojunctions with appreciable photoresponsivity. Solution-processed BaZrS 3 nanoparticles − and thin films − have been explored to realize low-cost optoelectronic devices. However, the role of extended defects, e.g., grain boundaries, dislocations, and crystalline domains, and interfaces during thin film growth and device fabrication, has not been systematically studied yet.…”

Synthesis of BaZrS3 and BaS3 Thin Films: High and Low Temperature Approaches

“…They prepared aqueous solutions containing either Ca 2+ or Zr 4+ ions bound directly to polymer molecules. A precursor film then is deposited using these two solutions, which subsequently has to be annealed to first remove the polymer, then sulfurize the film using CS 2 at 900 • C [34]. The solution approach by Turnley et al manages to reduce the synthesis temperature significantly by using a slurry of dissolved barium thiolate and zirconium hydride nanoparticles to deposit precursor films, which have to be dried and then sulfurized at 550 • C to obtain BZS as the primary product [35].…”