Preparation And Performance Of Luminescent Solar Concentrators Based On Carbon Dots And Perovskite Quantum Dots

Luminescent solar concentrator（LSC）is a new type of optoelectronic device integrating collection,conduction and conversion of solar energy,which plays an important role in the development of Building Integrated Photovaltaic（BIPV）.Unlike traditional photovoltaic equipment,LSC has the advantages of low cost,simple preparation,high light collection efficiency,the use of scattered light,a variety of shapes,and adjustable transparency/color.However,the current efficiency of LSC is relatively low,and the stability of the device is relatively poor.As the core component of LSC,fluorescent materials play a key role in determining the performance of LSC,therefore,this thesis uses blue-white/yellow-white carbon dots with wide photoluminescence（PL）emission and high photoluminescence quantum yield（PLQY）perovskite quantum dots as fluorescent materials to prepare single-node and multi-node LSCs,and then explores the effects of different fluorescent materials,material concentrations and different structures on LSC performance,and the main results are as follows:（1）Carbon dots with blue-white emission（BWCD）and carbon dots with yellow-white emission（YWCD）were synthesized by solvothermal method and applied to LSCs.Specifically,trisodium citrate dihydrate and glutathione were used as carbon and nitrogen sources,and the synthesized carbon dots had uniform particle size（2.5-4 nm）,wide PL emission range（400-700 nm）and stable properties.Using citric acid and urea as carbon and nitrogen sources and toluene as solvent,yellow-white emission carbon dots with high PL quantum yield（PLQY）and double emission peaks（450 nm and 580 nm）were synthesized.The PL emission range of YWCD also covered 400-700 nm.In addition,the application of this YWCD to a luminescent solar concentrator exhibits excellent transmittance（～70%）and good external optical efficiency（up to 1.36%）.And external optical efficiency of LSC based on YWCD reach to 2.61%,with 50%of transmittance in the range of 500 nm to 800 nm.（2）CsPbI₃（RQD）/CsPbBr₃（GQD）quantum dots with red/green emission were synthesized by thermal injection,and LSCs based on G/RQD were prepared at different concentrations,among which the external optical efficiency of G/RQD-based LSCs reached the highest 3.08%and 2.55%,respectively.Moreover,by combining with the previously synthesized BWCD,three different tandem LSCs were prepared,among which the fluorescence spectrum of multi-node LSCs with blue-white,red,and green light emission covered the entire visible spectral range,and this tandem structure made the external optical efficiency of LSCs reach to3.76%.（3）By using the above synthesized yellow-white light carbon dots and perovskite quantum dots.LSCs based on yellow-white light carbon dots and GQD,yellow-white light carbon dots and RQD,yellow-white light carbon dots and G/RQD have been made,respectively.The optical and photoelectric properties of three kinds of LSCs were studied.The fluorescence emission spectra of the three-tandem fluorescent solar collector based on G/RQD and yellow-white light carbon dot have four emission peaks of 450 nm,515 nm,580 nm and 670nm,covering the whole visible spectrum.Due to the high PLQY of the three fluorescent materials,the PLQY of the yellow-white light carbon dot is 51.36%,the PLQY of GQD is71.05%,and the PLQY of RQD is 68.29%,the external optical efficiency of the three-tandem LSC reache to 6.04%,while maintaining the optical transmittance of more than 60%within550 nm to 800 nm.