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

authored by

Denis Pluta, Henning Kuper, Rebecca T. Graf, Christoph Wesemann, Pascal Rusch, Joerg August Becker, Nadja C. Bigall

Abstract

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.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry
Laboratory of Nano and Quantum Engineering
PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines

Type

Article

Journal

Nanoscale Advances

Volume

5

Pages

5005-5014

No. of pages

10

Publication date

14.08.2023

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Bioengineering, Atomic and Molecular Physics, and Optics, Chemistry(all), Materials Science(all), Engineering(all)

Electronic version(s)

https://doi.org/10.1039/d3na00404j (Access: Open)