Department of Physics; Institute of Advanced Material
Methylammonium-based perovskite compounds are generally grown on conducting or semiconducting substrates for high performance solar cell applications. In this study, we explore the growth of these compounds on insulators and test for their field-effect transistor performance. The key challenge is to find a surface that favors the crystal growth of perovskites without compromising the adhesion of the crystals. A family of methacrylate-based polymers has been identified as the insulators. Onto these insulators, methylammonium lead iodide polycrystalline thin films were grown. Generally, we found that the crystal size in the perovskite layers is well-correlated with the surface hydrophobicity. More hydrophobic polymer layers favor the growth of larger crystals, but result in less favorable adhesion of the perovskite. Methacrylate polymers with a phenyl substituent can give better adhesion and crystal sizes despite their hydrophobic properties. Among the different insulating polymer layers, we found that poly(phenyl methacrylate) (PPhMA), a derivative of the common commercial plastic poly(methyl methacrylate) (PMMA), produces the best perovskite films. The molecular origin of these properties is discussed. To test the electronic properties of these films, we employed them for thin-film transistor applications. Under optimal conditions, the thin-film transistors fabricated on PPhMA produce the best device with an electron mobility of 0.4 cm2 V−1 s−1. Our results are also supported by photothermal deflection spectroscopy investigations of the subgap optical absorptions of these films.
Source Publication Title
Royal Society of Chemistry
This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Support of this research by the research committee of HKBU and the Research Grant Council of Hong Kong under Grant #’s FRG2/14-15/092, HKBU211913 and HKBU12201914 is gratefully acknowledged.
Link to Publisher's Edition
Ngai, J., Ho, J., Chan, R., Cheung, S., Leung, L., & So, S. (2017). Growth, characterization, and thin film transistor application of CH3NH3PbI3 perovskite on polymeric gate dielectric layers. RSC Advances (78), 49353-49360. https://doi.org/10.1039/C7RA08699G
Additional FilesGrowth, characterization, and_suppl.pdf (478 kB)