Issue 41, 2019

Colloidal PbS nanoplatelets synthesized via cation exchange for electronic applications

Abstract

In this work, we present a new synthetic approach to colloidal PbS nanoplatelets (NPLs) utilizing a cation exchange (CE) strategy starting from CuS NPLs synthesized via the hot-injection method. Whereas the thickness of the resulting CuS NPLs was fixed at approx. 5 nm, the lateral size could be tuned by varying the reaction conditions, such as time from 6 to 16 h, the reaction temperature (120 °C, 140 °C), and the amount of copper precursor. In a second step, Cu+ cations were replaced with Pb2+ ions within the crystal lattice via CE. While the shape and the size of parental CuS platelets were preserved, the crystal structure was rearranged from hexagonal covellite to PbS galena, accompanied by the fragmentation of the monocrystalline phase into polycrystalline one. Afterwards a halide mediated ligand exchange (LE) was carried out in order to remove insulating oleic acid residues from the PbS NPL surface and to form stable dispersions in polar organic solvents enabling thin-film fabrication. Both CE and LE processes were monitored by several characterization techniques. Furthermore, we measured the electrical conductivity of the resulting PbS NPL-based films before and after LE and compared the processing in ambient to inert atmosphere. Finally, we fabricated field-effect transistors with an on/off ratio of up to 60 and linear charge carrier mobility for holes of 0.02 cm2 V−1 s−1.

Graphical abstract: Colloidal PbS nanoplatelets synthesized via cation exchange for electronic applications

Supplementary files

Article information

Article type
Paper
Submitted
20 Mar 2019
Accepted
31 May 2019
First published
05 Jun 2019
This article is Open Access
Creative Commons BY license

Nanoscale, 2019,11, 19370-19379

Colloidal PbS nanoplatelets synthesized via cation exchange for electronic applications

L. Sonntag, V. Shamraienko, X. Fan, M. Samadi Khoshkhoo, D. Kneppe, A. Koitzsch, T. Gemming, K. Hiekel, K. Leo, V. Lesnyak and A. Eychmüller, Nanoscale, 2019, 11, 19370 DOI: 10.1039/C9NR02437A

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