Proceedings of nanoGe Fall Meeting 2021 (NFM21)
Publication date: 23rd September 2021
Ligand-free CsPbBr3 rounded cubes (RC) with average size of 3 μm have been prepared via a facile solution process under ambient conditions. The ability to grow directly the microcrystals onto electrodes provides a simple and low-cost method for the fabrication of high-performance perovskite-sensing elements, operating at room temperature without external stimuli (heating or UV irradiation). We show that the ambient synthesis conditions results in the growth of imperfect, rounded cube-shaped crystals. It is revealed that this shape favored the gas sensing process and as a consequence the RC-based sensors exhibited superior sensing performance compared to regular CsPbBr3 cubes (capable to detect 187 ppb ozone concentration) synthesized in inert atmosphere.1 The RC detect 4 ppb of ozone concentration with sensitivity of 13% at room temperature. Their response and recovery times at this low concentration, lays at 74 s and 15 s, respectively. RC-based sensor show also remarkable stability over consecutive cycles and after 3 months its storage in ambient conditions, without obvious alterations in morphology and crystal structure. At the same time, RCs proved to be superior hydrogen sensors, exhibiting capability to detect 1 ppm of hydrogen concentration. Both gas sensors developed, exhibit the lowest reported gas detection limits at room temperature compared to state-of-the art semiconductor materials, providing new opportunities in gas sensing applications. The enhanced sensitivity as well as the ease of the preparation method makes CsPbBr3 RCs as a good candidate for the detection of other types of gases as well.
This work was supported by the FLAG-ERA grant PeroGaS by General Secretariat for Research and Innovation (GSRI) (MIS 5070514). K.B. acknowledges E.U. H2020 Research and Innovation Program under Grant Agreement N820677 and Greek State Scholarships Foundation (IKY) through the operational Program «Human Resources Development, Education and Lifelong Learning» in the context of the project “Reinforcement of Postdoctoral Researchers - 2nd Cycle” (MIS-5033021). A.K. acknowledges the Hellenic Foundation for Research and Innovation (HFRI) and the General Secretariat for Research and Innovation (GSRI), under Grant Agreement No 1179 funded this project. We would like also to thank Mrs Alexandra Manousaki technical assistant of the SEM microscope at the Electron Microscopy Laboratory of the University of Crete.This work is a collaboration with the Transparent Conductive Materials (TCM) Laboratory at IESL-FORTH and Dr. Emmanuel Gagaoudakis, Mrs Vasiliki Faka, Dr. Vassilios Binas and Prof. George Kiriakidis.