Grain engineering for improved charge carrier transport in two-dimensional lead-free perovskite field-effect transistors

Abstract
Controlling crystal growth and reducing the number of grain boundaries are crucial to maximize the charge carrier transport in organic–inorganic perovskite field-effect transistors (FETs). Herein, the crystallization and growth kinetics of a Sn(II)-based 2D perovskite, using 2-thiopheneethylammonium (TEA) as the organic cation spacer, were effectively regulated by the hot-casting method. With increasing crystalline grain size, the local charge carrier mobility is found to increase moderately from 13 cm2 V−1 s−1 to 16 cm2 V−1 s−1, as inferred from terahertz (THz) spectroscopy. In contrast, the FET operation parameters, including mobility, threshold voltage, hysteresis, and subthreshold swing, improve substantially with larger grain size. The optimized 2D (TEA)2SnI4 transistor exhibits hole mobility of up to 0.34 cm2 V−1 s−1 at 295 K and a higher value of 1.8 cm2 V−1 s−1 at 100 K. Our work provides an important insight into the grain engineering of 2D perovskites for high-performance FETs.

Citation
Wang, S., Frisch, S., Zhang, H., Yildiz, O., Mandal, M., Ugur, N., Jeong, B., Ramanan, C., Andrienko, D., Wang, H. I., Bonn, M., Blom, P. W. M., Kivala, M., Pisula, W., & Marszalek, T. (2022). Grain engineering for improved charge carrier transport in two-dimensional lead-free perovskite field-effect transistors. Materials Horizons. https://doi.org/10.1039/d2mh00632d

Acknowledgements
S. Wang thanks the China Scholarship Council (CSC, 201906890035) for financial support. M. Mandal acknowledges postdoctoral support from the Alexander von Humboldt Foundation. T. Marszalek acknowledges the Foundation for Polish Science financed by the European Union under the European Regional Development Fund (POIR.04.04.00-00-3ED8/17). The authors thank Dr Hao Wu for the help with UPS measurements. This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – project number 424708673 and by the KAUST Office of Sponsored Research (OSR). Open Access funding provided by the Max Planck Society.

Publisher
Royal Society of Chemistry (RSC)

Journal
MATERIALS HORIZONS

DOI
10.1039/d2mh00632d

Additional Links
http://xlink.rsc.org/?DOI=D2MH00632D

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