Study On Preparation Of Luminescent Solar Concentrator Based On Carbon Dots And Copper Iodide Based Hybrid Nanoparticles

As a new type of solar energy collection device,the principle of luminescent solar concentrator（LSC）is mainly to use luminophores to absorb sunlight and re-emit fluorescence at longer wavelengths,most of which will be confined in the waveguide due to total reflection effect and converge at the edge of the LSC,and then be absorbed by the side-coupled solar cells and converted into electricity.Among the many luminophores used in LSC,carbon dots（CDs）stand out for their tunable absorption spectra,high photoluminescence quantum yield（PL QY）,low toxicity,low cost and easy synthesis.To further prepare high-efficiency LSC based on CDs,this thesis focuses on optimizing the optical properties of luminophores,improving the compatibility between luminophores and polymer matrix,and rationally designing the structure of tandem LSCs.The specific research results are as follows:（1）Organosilane grafted carbon dots（Si-CDs）were synthesized by hydrothermal method using anhydrous citric acid,ethanolamine and N-[3-（trimethoxysilyl）propyl]ethylenediamine（KH-792）as raw materials.Meanwhile,Polyvinyl alcohol（PVA）was used as a film-forming agent to chemically disperse Si-CDs in the PVA matrix through the dehydration condensation reaction between the silicon hydroxyl group of Si-CDs and the hydroxyl group of PVA and hydrogen bonding,which resulted in the preparation of Si-CDs/PVA based LSC with high Si-CDs loading（25 wt%）.Si-CDs/PVA based LSC not only exhibits excellent absorption properties in the ultraviolet part,but also has a high transmittance of about 90%in the visible part.In addition,Si-CDs/PVA based LSC can achieve a power conversion efficiency（PCE）of 2.09%.（2）Yellow emissive carbon dots（CDs:Ba）prepared with sodium citrate,urea and barium chloride dihydrate as raw materials via the solvothermal method.Since the introduction of Ba²⁺ions facilitates the formation of high crystallinity carbon cores by dehydration and carbonization among the raw materials,CDs:Ba can exhibit an ultra-high PL QY of 91.1%.Meanwhile,CDs:Ba/PMMA based LSC with a PCE of 2.82%were prepared by the drop-coasting method using polymethylmethacrylate（PMMA）as the film-forming agent and CDs:Ba as the luminophores.（3）The nano-sized Cu₄I₆（pr-ted）₂ nanoparticles（Cu₄I₆（pr-ted）₂NPs）were prepared by dispersion and stabilization of copper iodide inorganic modules(Cu₄I₆^2-)with long-chain polymers polyvinylpyrrolidone（PVP）followed by reaction with pr-ted ligands.Cu₄I₆（pr-ted）₂ NPs not only have large Stokes shift but also exhibit up to92.2%of PL QY.Then,Cu₄I₆（pr-ted）₂ NPs/PVP based LSC with a PCE of 3.59%was prepared by spin-coating method using PVP as the film-forming agent.When Cu₄I₆（pr-ted）₂ NPs/PVP based LSC and CDs:Ba/PMMA based LSC consist of tandem LSCs,the PCE of the tandem LSCs can reach 6.29%.