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Subject of the Master's internship

Perovskite nanoplatelets for hybrid photodetectors

​​​PhD may follow. Page Web française.
Published on 12 October 2021
Interfaces between metal halide perovskite materials and two-dimensional (2D) transition metal dichalcogenides (TMDC) hold great promises for the development of smart photodetector devices, as they combine two classes of model materials displaying exceptional optoelectronic properties. The halide perovskites can be used as broadband TMDC sensitizer to enhance the optical absorption of the active layer and allow efficient separation of the photogenerated charges. Combined with the low dimensionality of electric field-tunable TMDCs it provides an ideal platform for smart photodetectors, which is a hot topic in modern science. In the framework of an ongoing collaborative project, we aim at fabricating of CsPbX3-nanocrystalX/MoS2 photodetectors. As a first step, we have recently optimized the synthesis and deposition of colloidal metal halide perovskite nanocrystals on Si and MoS2.

Perovskite nanoplatelets (NPs) have a high potential for use in heterojunction photodetectors due to their enhanced electronic coupling with the TMDCs because of their ultrathin, smooth surfaces and atomic layer precise control of thickness, which via 2D quantum confinement gives a very precise control of the band gap and exciton binding energy.

In this internship project, we will study the influence of the thickness and composition of CsPbX3 NPs by controlling the synthesis conditions. As a starting point, we will use a simple one-pot approach giving access to high-purity ultrathin CsPbBr3 NPs, which can be modified to achieve thicker ones (4-6 unit cells). In addition, to date, all reported all-inorganic perovskite NPs are restricted to the blue emission range. Therefore, the composition and synthesis conditions will be optimised to obtain novel NPs to access narrower bandgaps. Special attention will be paid to the surface functionalisation before integrating the NPs in the TMDC-based detectors. The NPs and films will be studied using optical spectroscopies, electron (SEM/TEM) and near-field (AFM, KPFM) microscopies.

Background and skills expected
Chemistry of (nano)materials: inorganic and/or organic chemical synthesis, Schlenk line experience are welcomed.

Competences that will be acquired during the internship
Nanocrystals synthesis; deposition; optical, electronic and morphological study of nanomaterials.

Supervisor(s): Dmitry Aldakov (mail - Bio - Phone: +33438784660 ), Benjamin Grévin (Bio )
Laboratory: SyMMES (Molecular Systems and Nanomaterials for Enregy and Health) laboratory
Team/Group: STEP (Synthesis, Structure and Properties of Functional Materials)
This Master internship could be followed into a PhD within the same research area

1 J. Ye, Y. Li, A. A. Medjahed, S. Pouget, D. Aldakov, Y. Liu and P. Reiss, Small, 2021, 17, 2005671.
2 P. A. Fernández Garrillo, L. Borowik, F. Caffy, R. Demadrille, B. Grévin ACS Appl. Mater. Interfaces 2016, 8, 31460
3 M. C. Weidman, A. J. Goodman, W. A. Tisdale Chem. Mater. 2017, 29, 5019