Preparation Of CdS Quantum Dots For Solar Cells

Solar energy,as a kind of environment-friendly,renewable energy was widely concerned all over the world.With the development of solar energy utilization technology,Solar cell industry has gradually grown up.Semiconductor CdS quantum dots（CdS QDs）shows the advantages of adjustable emission wavelengths and high electron transport efficiency.It can be used as both light-absorbing material and battery transmission material in the solar cell.So,it Plays an important role in the field of dye-sensitized solar cells（DSSCs）and perovskite solar cells（PSCs）.In this paper,Oil-soluble monodisperse CdS quantum dots was prepared through homogeneous hydrothermal method,And applied to QDSSCs and PSCs,respectively.Then,the photoelectric properties of the batteries was studied.The main research contents and results are as follows:（1）Synthesis of CdS Quantum Dots with controlled particle size Homogeneous Method.In the high-pressure reactor,CdCl₂ as cadmium source,sublimed sulfur as sulfur source,CdS quantum dots were successfully synthesized.The quantum dots with different particle sizes are obtained by regulating the reaction time of water heat and the reaction temperature.The UV-Vis absorption spectra of the synthesized products shown: with the increase of reaction time and reaction temperature,the first absorption peak of uv absorption spectra are red-shifted,The emission peak of the fluorescence emission spectrum of the synthesized product also showed a red shift phenomenon.When the reaction temperature was 180 ℃,the reaction time increased from 0.5h to 4h,TEM analysis showed that the product particles increased gradually,The particle size range is 3 to 7 nm.This result is consistent with the results of UV and fluorescence analysis.At 180℃and 2 h,The well dispersibility of the synthesized product was observed by transmission electron microscopy（TEM）,and the particle size was about 6.4 nm.The results of XRD,HRTEM and SAED analysis can be used to determine the successful preparation of CdS quantum dots.（2）CdS QDs was used as light-absorbing material for quantum dot-sensitized cells,The TiO₂ nanometer tree array（TNTs）was synthesized on the surface of FTO glass by secondary hydrothermal method,The CdS quantum dots with particle size of 6.4 nm were spin-coated on the TiO₂ nanostructures was arrayed to form the photocathodes of solar cells.The results show that CdS QDs can be successfully used as a light-absorbing material for batteries to prepare solar cells with better photoelectric performance.When the number of spin coating is 12 times,the battery short-circuit current can reach 17.84 mA/cm²,the total efficiency of the battery is 3.69 %.At the same time,the photoelectric properties of TiO₂-TNTs films were compared with the traditional TiO₂ mesoporous films.The short-circuit current and photoelectric conversion efficiency of TiO₂-TNTs were increased from 9.60 mA·cm^-2 and 2.46 % of conventional TiO₂ mesoporous films to 17.84 mA·cm^-2 and 3.69 %,respectively.However,the electrochemical impedance decreased from 241.77 ? to 195.3 ?.（3）This paper have studied the Photoelectric Properties of Perovskite Solar Cells（PSCs）with Electronically Transferable Materials of CdS QDs.The CdS QDs with a particle size of 6.4 nm were spin-coated onto the surface of the blank glass,then the material was prepared by low temperature heat treatment as the electron transport material of PSCs.The effect of thin layer thickness of CdS QDs on the photoelectric properties of the cells was studied.The results show that CdS QDs,as the electron transport material of PSCs,exhibited good electron transport capacity.When the solubility of CdS cyclohexane solution is 0.6 mol / L and the number of spin coating is 4 times,the thickness of CdS layer is 337 nm,the performance of the battery is the best,the electron transport rate is fast and the compound is slow.At this time,the battery short-circuit current is 17.36 mA/cm²,open circuit voltage is 1.04 V,fill factor is 0.671,the battery photoelectric conversion efficiency is12.11 %.