Affiliation: | 1. Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ UK;2. Department of Chemistry and Center for Plastic Electronics, Molecular Science Research, Imperial College London, White City Campus, Wood Lane, London, W12 0BZ UK;3. Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, WC1E 7JE UK;4. Department of Chemistry and Center for Plastic Electronics, Molecular Science Research, Imperial College London, White City Campus, Wood Lane, London, W12 0BZ UK Department of Materials and Center for Plastic Electronics, Imperial College London, South Kensington Campus, London, SW7 2AZ UK;5. Department of Materials and Center for Plastic Electronics, Imperial College London, South Kensington Campus, London, SW7 2AZ UK;6. Department of Chemistry and Center for Plastic Electronics, Molecular Science Research, Imperial College London, White City Campus, Wood Lane, London, W12 0BZ UK SPECIFIC, College of Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN UK |
Abstract: | The room temperature synthesis of perovskite nanocrystals (NCs) is typically achieved by employing a ligand-assisted reprecipitation (LARP) method, which can be handled in air, and its products are comparable to what is obtained using the traditional hot-injection method. However, the LARP method typically requires the use of coordinating polar solvents such as dimethylformamide, which are not appropriate for large-scale production due to toxicity concerns and can also degrade or form defective perovskite NCs. Herein, an amine and oleic-acid-free room temperature synthesis of lead bromide perovskite NCs is reported that uses a combination of trioctylphosphine oxide and diisooctylphosphinic acid ligands. This combination of ligands provides a stable platform for the polar-solvent-free synthesis in air of fully inorganic CsPbBr3 (fwhm ≈ 14 nm, emission = 519 nm) and hybrid organic-inorganic FAPbBr3 (fwhm ≈ 19 nm) NCs with photoluminescence emission between 530 and 535 nm, which is in line with the Rec. 2020 color standards. In addition, it is shown that compared to a traditionally used ligand combination, phosphine ligands can be easily removed from the surface of the NCs, which is important for the future development of this technology in optoelectronic devices. |