LUminescent nanocoMposites by pulsed Injection of solutions iN plasmA – LuMINA

Because of their potential applications in lighting devices, white light emitting materials are of great interest to researchers. Application areas covered include information display devices, fluorescent sensors and solid-state lighting. In order to protect the phosphors and maintain their emission performance, one strategy is to embed them in a transparent organic or preferably inorganic matrix. Indeed, an inorganic matrix generally has a better UV resistance. Among the possible oxides meeting the specifications of the host matrix, silica has been identified as a suitable candidate due to its transparency, chemical stability, biocompatibility, and non-toxicity. The joint use of optically active nanoparticles (NPs) uniformly distributed within such a matrix offers numerous possibilities for the application of these new composite materials (NC).
LuMINA aims to synthesise NC films based on photoluminescent, optically efficient ZnO NPs embedded in a protective and transparent silica matrix. Indeed, with about 125,000, 1,000 and 300 publications and an increase of 4, 3 and 20 times identified in the Web of Science in March 2021 on "NC", "NC based on ZnO NPs", and "NC SiO2 and ZnO", these materials have all the properties for the targeted applications.
On the one hand, from a material point of view, our objective is to prepare photoluminescent thin films from stable colloidal solutions of ZnO NPs smaller than 10 nm, fabricated in the laboratory. Stabilised in organic solutions by ligands, the NPs will be injected to form an aerosol and dispersed in a high optical quality silica matrix prepared in a plasma enhanced chemical vapour deposition (PECVD) reactor. We will monitor their spatial dispersion in the matrix and evaluate if and how the surface defects of the NPs are affected by the plasma process. To this end, the variations in the emission wavelength and light intensity of the photoluminescence (PL) signal of the NPs will be studied. We will also determine the optimal amount of NPs to incorporate in order to maximise the PL properties.
On the other hand, in terms of process, our objective is to characterize and optimize the aerosol-assisted plasma process coupling the pulsed injection of a colloidal solution of NPs to a low pressure and low temperature plasma, for the deposition of NC thin films. This requires a better description and control of the aerosol and its interaction with the plasma, called, in this case, misty plasma by analogy with dusty plasma.
The consortium allows for a multidisciplinary approach, ranging from chemistry at the LCC, plasma physics at Laplace to the fabrication of NC, their structural characterisation and the evaluation of their properties at IMN. More precisely, the proposed work extends from organometallic chemistry to the characterisation of the final materials and their optical properties by considering the different stages of the process: dispersion, injection, plasma physics, plasma-aerosol interactions as well as plasma-surface mechanisms. In order to study these different steps, the proposal is organised around 4 research tasks and one project management task.
The researchers from IMN, Laplace and LCC, whose skills are complementary, already have experience of working in a multidisciplinary approach, which will facilitate exchanges and interactions between the partners and guarantee the smooth progress of the project.