Proceedings of MATSUS Fall 2024 Conference (MATSUSFall24)
DOI: https://doi.org/10.29363/nanoge.matsusfall.2024.087
Publication date: 28th August 2024
The colloidal synthesis of two-dimensional (2D) lead chalcogenide semiconductors yields near-infrared emissive materials with strong excitonic contribution at room temperature.[1-4] They are model systems for efficient charge carrier multiplication and hold potential as intriguing candidates for fiber-based photonic quantum applications. However, synthetic access to the third family member, 2D lead telluride (PbTe), remains elusive due to a challenging precursor chemistry. Here, we report a direct synthesis for 2D PbTe nanoplatelets (NPLs) with tunable photoluminescence (PL, 910 – 1460 nm (1.36 – 0.85 eV), PLQY 1 – 15 %), based on aminophosphine precursor chemistry.[1] Our NMR study underpins the synthetic importance of an ex-situ transamination of tris(dimethylamino)phosphine with octylamine to yield a reactive tellurium precursor for the formation of 2D PbTe NPLs at temperatures as low as 0 °C. Associated GIWAXS measurements confirm the 2D geometry of the NPLs and the formation of superlattices. The importance of a post-synthetic passivation of PbTe NPLs by PbI2 to ensure colloidal stability of the otherwise oxygen sensitive samples is supported by X-ray photoelectron spectroscopy. Our results expand and complete the row of lead chalcogenide-based 2D NPLs, opening up new ways for further pushing the optical properties of 2D NPLs into the infrared and toward technologically relevant wavelengths.