TY - JOUR

T1 - Interparticle Distance Variation in Semiconductor Nanoplatelet Stacks

AU - Graf, Rebecca T.

AU - Schlosser, Anja

AU - Zámbó, Dániel

AU - Schlenkrich, Jakob

AU - Rusch, Pascal

AU - Chatterjee, Atasi

AU - Pfnür, Herbert

AU - Bigall, Nadja C.

N1 - Funding Information: R.T.G. and A.S. contributed equally to this work. N.C.B. thanks the European Research Council (ERC) for financial support under the European Union's Horizon 2020 research and innovation program (grant agreement 714429). Furthermore, this work was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) under Germany's excellence strategy within the cluster of excellence PhoenixD (EXC 2122, project ID 390833453). R.T.G. and A.S. thank the Hannover School for Nanotechnology (HSN) for funding. D.Z. acknowledges the program financed by the National Research, Development, and Innovation Office of the Ministry for Innovation and Technology, Hungary (TKP2021‐NKTA‐05). The authors are thankful to the Laboratory of Nano and Quantum Engineering (LNQE) for providing the TEM facilities and Jürgen Caro and Armin Feldhoff for the SEM‐EDX facilities. Additionally, the authors are grateful to Frank Steinbach for the SEM cross‐section measurements. Furthermore, the authors would like to thank Jörg Fohrer and the whole NMR department of the Institute of Organic Chemistry at Leibniz Universität Hannover for the NMR measurements. Funding Information: R.T.G. and A.S. contributed equally to this work. N.C.B. thanks the European Research Council (ERC) for financial support under the European Union's Horizon 2020 research and innovation program (grant agreement 714429). Furthermore, this work was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) under Germany's excellence strategy within the cluster of excellence PhoenixD (EXC 2122, project ID 390833453). R.T.G. and A.S. thank the Hannover School for Nanotechnology (HSN) for funding. D.Z. acknowledges the program financed by the National Research, Development, and Innovation Office of the Ministry for Innovation and Technology, Hungary (TKP2021-NKTA-05). The authors are thankful to the Laboratory of Nano and Quantum Engineering (LNQE) for providing the TEM facilities and Jürgen Caro and Armin Feldhoff for the SEM-EDX facilities. Additionally, the authors are grateful to Frank Steinbach for the SEM cross-section measurements. Furthermore, the authors would like to thank Jörg Fohrer and the whole NMR department of the Institute of Organic Chemistry at Leibniz Universität Hannover for the NMR measurements. Open access funding enabled and organized by Projekt DEAL.

PY - 2022/6/8

Y1 - 2022/6/8

N2 - In the large field of research on nanoplatelets (NPLs), their strong tendency to self-assemble into ordered stacks and the resulting changes in their properties are of great interest. The assembly reveals new characteristics such as the charge carrier transport through the NPL assembly or altered optical properties. In particular, a reduced distance should enhance the charge carrier transport due to higher electronic coupling of neighboring NPLs, and therefore, is the focus of this work. To modify the inter-particle distances, the straightforward method of ligand exchange is applied. Various CdSe and CdSe/CdX (hetero-) NPLs serve as building blocks, which not only display different material combinations but also different types of heterostructures. The surface-to-surface distance between the stacked NPLs can be reduced to below 1 nm, thus, to less than the half compared to assemblies of pristine NPLs. Moreover, for certain NPLs stacking is only enabled by the ligand exchange. To characterize the ligand exchanges and to investigate the influences of the reduced distances, photo-electrochemical measurements, fluorescence spectroscopy, energy dispersive X-ray spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy are performed. It is possible to show higher photocurrents for smaller distances, indicating enhanced charge transport ability within those stacks.

AB - In the large field of research on nanoplatelets (NPLs), their strong tendency to self-assemble into ordered stacks and the resulting changes in their properties are of great interest. The assembly reveals new characteristics such as the charge carrier transport through the NPL assembly or altered optical properties. In particular, a reduced distance should enhance the charge carrier transport due to higher electronic coupling of neighboring NPLs, and therefore, is the focus of this work. To modify the inter-particle distances, the straightforward method of ligand exchange is applied. Various CdSe and CdSe/CdX (hetero-) NPLs serve as building blocks, which not only display different material combinations but also different types of heterostructures. The surface-to-surface distance between the stacked NPLs can be reduced to below 1 nm, thus, to less than the half compared to assemblies of pristine NPLs. Moreover, for certain NPLs stacking is only enabled by the ligand exchange. To characterize the ligand exchanges and to investigate the influences of the reduced distances, photo-electrochemical measurements, fluorescence spectroscopy, energy dispersive X-ray spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy are performed. It is possible to show higher photocurrents for smaller distances, indicating enhanced charge transport ability within those stacks.

KW - charge carrier transport

KW - distance variation

KW - ligand exchange

KW - nanoplatelets

KW - photo-electrochemistry

KW - self-assembly

KW - stacks

UR - http://www.scopus.com/inward/record.url?scp=85125376701&partnerID=8YFLogxK

U2 - 10.1002/adfm.202112621

DO - 10.1002/adfm.202112621

M3 - Article

AN - SCOPUS:85125376701

VL - 32

JO - Advanced functional materials

JF - Advanced functional materials

SN - 1616-301X

IS - 24

M1 - 2112621

ER -