Regensburg 2025 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 4: 2D Materials and their Heterostructures II (joint session DS/HL)

DS 4.9: Vortrag

Dienstag, 18. März 2025, 12:15–12:30, H3

Investigation of 1T-TaS2 phase transition and charge transfer phenomena at interfaces with perovskites — •Georgios Chatzigiannakis^1,2, Anastasia Soultati¹, Spiros Gardelis², and Maria Vasilopoulou¹ — ¹Institute of Nanoscience and Nanotechnology, National Centre of Scientific Research Demokritos, 15341 Athens, Greece — ²Department of Physics, National and Kapodistrian University of Athens, 15784 Athens, Greece

1T-TaS2 is a distinguished 2D-layered transition metal dichalcogenide with a rich phase diagram upon cooling including charge density wave (CDW) states and a Mott insulating phase. On the other hand, halide perovskites (HPs) are emerging as a unique class of materials in the field of photonics due to their intriguing optoelectronic properties. The combination of 1T-TaS2 with HPs is proposed as a viable solution to overcome the drawbacks of each category thanks to charge transfer phenomena.

In this work, we studied the phase transitions of 1T-TaS2 as a function of the cooling rate. In the case of nanothick crystals, CDW phase transitions were observed upon gradual cooling but they were totally absent afrer a vigorous cooling. On the contrary, for bulk crystals the CDW phase transitions were totally independent of the cooling rate. Furthermore, we developed 1T-TaS2/HPs heterostructures and we investigated charge transfer phenomena by XPS and UPS spectroscopy, both revealing electron transfer from 1T-TaS2 towards perovskite. Charge transfer could also enable the development of high-performance hybrid optoelectronic devices based on these materials.

Keywords: tantalum disulfide; perovskites; heterostructures; phase transitions; charge transfer