Development And Performance Of Near Infrared Quantum Dots Luminescent Solar Concentrator

Among the photons available to crystalline Si solar cells, about 60% of the solar photon flux occurs at wavelength greater than 600 nm. In order to utilize the solar radiation effectively and decrease the price of photovoltaic electricity, this thesis presented the fabrication process and performance of near infrared luminescent solar concentrator (NIR LSC), which utilizes 2.4±0.4 nm monodisperse lead sulfide (PbS) quantum dots (QDs) as the active fluorescent material. The dissertation contains three chapters. The first chapter gives a literature review. The second chapter is the synthesis and characterization of PbS quantum dots. The third chapter is the fabrication and characterization of NIR LSC.The first chapter is the introduction. First, the crisis of traditional energy and the importance of the renewable energy cause every country to develop solar energy. Second, the history of photovoltaic power, the principle and classification of solar cells and the development direction of solar cells are illustrated. Third part of this chapter reviews the luminescent solar concentrator. The concept and principle of LSC are explained. The fourth part reviews quantum dots, including the concept and physics properties of QDs, the progress of QDs synthesis by colloidal method and the advantages of QDs in NIR range. Finally, the significance of this research subject and the content of this dissertation are presented.The second chapter is the synthesis process, characterization and result analysis of PbS QDs. Lead oxide and bis(trimethylsilyl)sulfide were chosen as precursors, and trioctylphosphine was added as stabilizer to prepare PbS QDs using organometallic synthetic method. The XRD, HR-TEM and fluorescence spectroscopy characterization show that the monodisperse PbS QDs have uniform size and estimated about 30% quantum yield. The size and optical property of PbS QDs are affected by the concentration of reaction reagents. Controlling the synthesis condition, PbS QDs with 700-1000 nm absorption spectrum and 750-1100 nm emission spectrum was prepared.The third chapter is the construction and characterization of QD-LSC. By sandwiching the PbS QDs hexane solution, the 78 mm×78 mm NIR QD-LSC was constructed, coupling 17% commercial monocrystalline Si solar cells to the four edges of the QD-LSC, which absorbs 700-1000 nm solar radiation. The standard efficiency of the NIR LSC is upto 1.38%. Cascaded LSC was also formed with dye LSC, which extends the available spectral range of LSC. The total efficiency of cascaded LSC is increased to 3.4%.