AIBN Seminar Series: Student Seminars

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Universal Electrochemical Synthesis of Mesoporous Chalcogenide Semiconductors
This study aims to report a novel route for mesoporous chalcogenide semiconductor synthesis by employing soft-template-assisted electrochemical deposition. Mesoporous semiconductors have emerged as a new class of materials that can enable light reflection/scattering inside the nanopore structures, thus attracting a great deal of interest for optical sensors and solar cells. In addition, mesopores of chalcogenide semiconductors can be down-scaled below the electron mean free path, leading to interesting physical phenomena such as quantum confinement and surface scattering. Furthermore, the mesoporous structure enhances an electrochemical active surface area and facilitates ion exchange in alkaline ion batteries. These features expectedly open up the pathway to engineering optoelectronic systems, bio-sensor, and rechargeable batteries with unexplored capabilities. This work introduces an innovative and simple electrochemical approach to synthesizing 5 types of mesoporous chalcogenide semiconductors by employing a soft-template process with block copolymer micelles. The resulting mesoporous CdSe, CdTe, Cu2Se, CuTe, and Bi2Se3 films are stoichiometrically equivalent and contain mesopores homogeneously distributed over the entire surface. To demonstrate the versatility of this study, two block-copolymers with different molecular weights were used, yielding films with pores of either 9 or 18 nm diameter. This study shows three types of applications, photodetector by CdSe, glucose sensor by Bi2Se3, and Na-ion battery anode by Cu2Se. Those exhibit superior performance than the nonporous samples, proving that mesoporous structure has outstanding potential for optical, catalytic, and rechargeable battery applications. This work pioneers a new synthesis route for nanostructured semiconductors.

About Tomota:
Tomota is a final year PhD student at Yamauchi group. Tomota has received PhD in chemistry from the University of Tsukuba in Japan and has MPhil and undergraduate degrees in materials science in the Tokyo Institute of Technology. Tomota worked for 10 years as an engineer in R&D section in JX Nippon Mining and Metals, corp., and obtain the company's scholar to study in UQ. The company has been recently generating high profits from functional semiconductor and metallic materials, supported by the large demand in the semiconductor market. The synthesis method for mesoporous materials innovated by Yamauchi group would have much potential and benefit for developing novel functional materials. In fact, Tomota has reported four novel mesoporous chalcogenides in a peer-reviewed paper and demonstrated their respective applications.