Design And Synthesis Of Inorganic CsPbX₃ Quantum Dots And Their Potential Application For Solar Cells

Lead perovskite halide in the form of quantum dots or nanocrystals has attracted extensive attention by materials scientists due to its unique optical versatility,high photoluminescence quantum yield and mild synthesis conditions.In addition,the suitable band gap of such materials(for example,the band gap of a-CsPbI3 is 1.73eV)and simple solution process to form film expedite their potential application for solar cells.Recently,solar cells using a-CsPbI3 or CsPbIxBr(3-x)quantum dots as absorber have been developed in the different fields.However,the structure of CsPbX3 quantum dot is unstable when being exposed to polar solvent,light,oxygen and high temperature.It is easy to transfer from the excellent cubic phase into a more stable orthorhombic phase of poor performance.In addition,as for a-CsPbI3 perovskite quantum dot solar cells,the presence of long chain insulating ligands between the active layer a-CsPbI3 quantum dots is disadvantage to the charge transfer while thin thickness of a-CsPbI3 thin films limits the light absorption layer.Accordingly,these detrimental facts play negative role on the performance of solar cells.Herein,we carry out the following research for the above issues:1.CsPbI3 quantum dots with different emission wavelengths are firstly synthesized by thermal injection at different temperatures.Secondly,an epitaxial growth method is explored to grow Cs4PbBr6 shell materials.Finally,the study is found that aluminum doped in the shell by adding aluminum isopropanol is greatly helpful to stabilize CsPbBr3 quantum dots.2.To solve the problems of carrier transport and light absorption,well aligned titanium dioxide array is fabricated with a-CsPbI3 perovskite quantum dot for solar cells.Firstly,we design the forward structure ?-CsPbI3 perovskite quantum dot solar cells.Secondly,titanium dioxide array doped with niobium is grown to be the electron transport layer replacing the traditional plane titanium dioxide,and the height of the array is adjusted to 50nm by optimizing the preparation process.Finally,the investigation is obtained that the array layer has the positive effect of enhancing light transmittance and carrier collection.The efficiency of solar cells based on the array layer are better than that based on the normal structure.