TY - JOUR

T1 - Optical properties of NIR photoluminescent PbS nanocrystal-based three-dimensional networks

AU - Pluta, Denis

AU - Kuper, Henning

AU - Graf, Rebecca T.

AU - Wesemann, Christoph

AU - Rusch, Pascal

AU - Becker, Joerg August

AU - Bigall, Nadja C.

N1 - Funding Information: N. C. B. would like to thank the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) for funding under Germany's excellence strategy within the cluster of excellence PhoenixD (EXC 2122, project ID 390833453). D. P. and R. T. G. are thankful for support from the Hannover School for Nanotechnology (HSN). The authors thank the Laboratory of Nano and Quantum Engineering (LNQE) for providing the TEM facility.

PY - 2023/8/14

Y1 - 2023/8/14

N2 - The assembly of nanocrystals (NCs) into three-dimensional network structures is a recently established strategy to produce macroscopic materials with nanoscopic properties. These networks can be formed by the controlled destabilization of NC colloids and subsequent supercritical drying to obtain NC-based aerogels. Even though this strategy has been used for many different semiconductor NCs, the emission of NC-based aerogels is limited to the ultraviolet and visible and no near-infrared (NIR) emitting NC-based aerogels have been investigated in literature until now. In the present work we have optimized a gelation route of NIR emitting PbS and PbS/CdS quantum dots (QDs) by means of a recently established gel formation method using trivalent ions to induce the network formation. Thereby, depending on the surface ligands and QDs used the resulting network structure is different. We propose, that the ligand affinity to the nanocrystal surface plays an essential role during network formation, which is supported by theoretical calculations. The optical properties were investigated with a focus on their steady-state and time resolved photoluminescence (PL). Unlike in PbS/CdS aerogels, the absorption of PbS aerogels and their PL shift strongly. For all aerogels the PL lifetimes are reduced in comparison to those of the building blocks with this reduction being especially pronounced in the PbS aerogels.

AB - The assembly of nanocrystals (NCs) into three-dimensional network structures is a recently established strategy to produce macroscopic materials with nanoscopic properties. These networks can be formed by the controlled destabilization of NC colloids and subsequent supercritical drying to obtain NC-based aerogels. Even though this strategy has been used for many different semiconductor NCs, the emission of NC-based aerogels is limited to the ultraviolet and visible and no near-infrared (NIR) emitting NC-based aerogels have been investigated in literature until now. In the present work we have optimized a gelation route of NIR emitting PbS and PbS/CdS quantum dots (QDs) by means of a recently established gel formation method using trivalent ions to induce the network formation. Thereby, depending on the surface ligands and QDs used the resulting network structure is different. We propose, that the ligand affinity to the nanocrystal surface plays an essential role during network formation, which is supported by theoretical calculations. The optical properties were investigated with a focus on their steady-state and time resolved photoluminescence (PL). Unlike in PbS/CdS aerogels, the absorption of PbS aerogels and their PL shift strongly. For all aerogels the PL lifetimes are reduced in comparison to those of the building blocks with this reduction being especially pronounced in the PbS aerogels.

UR - http://www.scopus.com/inward/record.url?scp=85170679981&partnerID=8YFLogxK

U2 - 10.1039/d3na00404j

DO - 10.1039/d3na00404j

M3 - Article

AN - SCOPUS:85170679981

VL - 5

SP - 5005

EP - 5014

JO - Nanoscale Advances

JF - Nanoscale Advances

IS - 18

ER -