Tailoring the properties of luminescent downshifting layers with POSS Nanoparticles Helen Tunstall-Garcia, Bethan L. Charles, Rachel C. Evans University of Cambridge, UK Solar power has great promise as a renewable energy source. However, current photovoltaic (PV) technologies suffer from losses such as thermalisation and recombination, limiting their efficiencies. Spectral converters can overcome these problems by converting incident sunlight into wavelengths that better match the spectral response of an attached PV cell, for example by converting UV to visible light through luminescence downshifting (LDS). (1) These layers are deposited on top of the PV cell and thus must withstand significant weathering. While previous work has investigated nano-reinforced protective coatings with potential for solar cells (2) , such materials are yet to be adapted as host materials for LDS. In this work, we investigate the effect of polyhedral oligomeric silsesquioxanes (POSS) as additives in a polyethylene-co-glycidyl methacrylate (PE-GMA) host, both in the presence and absence of a fluorescent dye (Coumarin 1). POSS nanoparticles have shown great potential as thermal and mechanical reinforcements in polymeric materials, (3) and the resulting material is easily processable and tunable. Furthermore, the properties of light-emitting materials can be improved by the introduction of POSS, which has been shown to reduce aggregation-caused quenching and increase photostability.(4) Here, the host properties are assessed by studying the compatibility and polymer properties of a series of POSS-[PE-GMA] hybrid composite films without Coumarin 1. In order to examine the performance as LDS layers, the optical properties of the Coumarin 1-doped composite films are investigated using microscopy, transmittance, steady-state and time-resolved photoluminescence measurements. The knowledge gleaned through these studies will enable us to identify the optimum POSS reinforcement loading to obtain highly robust and efficient luminescent downshifters.
References 1. McKenna and R. C. Evans, Adv. Mater. , 2017, 29 , 1606491.
2. Fang, P. Wang, L. Sun and L. Wang, Nanomaterials , 2021, 11 , 472. 3. Zhou, Q. Ye and J. Xu, Mater. Chem. Front. , 2017, 1 , 212–230. 4. Tunstall-Garcia, B. L. Charles and R. C. Evans, Adv. Photonics Res. , 2021, 2 , 2000196.
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