Functionalisation of InP quantum dot surfaces Ashleigh Cartlidge , T. A. Gazisand, Peter Matthews Department of Chemistry, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, a.j.cartlidge@keele.ac.uk In recent decades, Quantum Dots (QDs) have captured the attention of researchers spanning several fields due to their tuneable optoelectronic properties. First discovered in the 1980’s, these nanoscale ‘artificial atoms’ are typically formed from II-VI semiconductors, such as CdSe; however, with rising concerns over the safety of such materials, attention has shifted towards III-V types, most notably InP. 1-4 Fundamentally, InP QDs should exhibit good emissive properties, but surface states and residual precursor dangling bonds result in the need for further modification of InP. Several examples of surface modification see the use of hard etchants, and multi-layer shelling as a means to passivate deep trap states, but doing so can impact the overall size tuneability. 1-4 As part of a scoping study, purified InP QDs were treated with an array of halogen sources in an attempt to functionalise the surface of the QD, and thereby enhance the overall fluorescent properties by overcoming the issues associated with the surface chemistry of InP QDs. It was observed that the addition of a select halide source appears to functionalise the QD surface, resulting in an observable blue-shift of ~ 200 nm and improved fluorescent behaviour. The mechanism for this was investigated systematically to better understand the way in which halide addition alters the starting QD. Armed with this functionalisation, attempts were then made to enforce cyclability within the system whereby altering reaction conditions could yield either the QD at 560 nm, or the functionalised species at 360 nm and 320 nm (Figure 1).
Figure 1 The UV data for an experiment whereby the starting Quantum Dot (QD) is functionalised through the addition of a halide source. This functionalisation is observed by the significant blue-shift to the species forming at 360 nm and 320 nm. References 1. T. A. Gazis, A. J. Cartlidge, P. D. Matthews, J. Mater. Chem. C., 2023, 11 , 3926-3935. 2. T. A. Gazis, P. D. Matthews, Chem. Commun., 2022, 58 , 13799. 3. B. M. Cossairt, Chem. Mater., 2016, 28 , 7181-7189. 4. S. M. Click, S. J. Rosenthal, Chem. Mater., 2023, 35 , 3, 822 – 836.
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