Preparation And Properties Of Carbon-based All-inorganic CsPbBr₃ Perovskite Solar

Environment-friendly and pollution-free perovskite solar cells（PSCs）have excellent photoelectric performance.In rencent years,the efficiency and stability of perovskite solar cells are steadily improving.However,the traditional organic-inorganic hybrid metal halide perovskite solar cells are relatively sensitive to heat and humidity due to the presence of organic components,and are prone to generate Pb I₂ under the environmental conditions of moisture,oxygen and heat,which is very unstable.In addition,the hole transport materials and precious metal electrode materials in the traditional PSCs structure are not only unstable in the atmospheric environment,but also very expensive.Special atmosphere protection is often required in the preparation process,which is very unfavorable to the production and application of perovskite solar cells from the laboratory.Therefore,in order to solve the above problems,we abandoned the traditional expensive hole transport layer,took carbon electrode as the back electrode,and selected all-inorganic perovskite material Cs Pb Br₃ as the light absorption layer of PSCs,and last but not least,the study was carried out in the air environment without any atmosphere protection.The research content of this paper is as follows:（1）Considering the heat and humidity resistance of the battery device and the cost of the battery itself,we adopt the all-inorganic perovskite film Cs Pb Br₃ as the light absorption layer of the perovskite solar cell.Cs Pb Br₃thin films were prepared by a two-step method in the air without any atmosphere protection,and were assembled as FTO/c-Ti O₂/m-Ti O₂/Cs Pb Br₃/C mesoscopic perovskite solar cells and preliminary-explored.The PCE of all inorganic Cs Pb Br₃ perovskite solar cells prepared with carbon electrode in air was 2.57%.（2）The all-inorganic Cs Pb Br₃perovskite film,which is the light absorbing layer of perovskite solar cell devices,was prepared by two-step spin-coating method in the air without any atmosphere protection.The influence of the number of spin-coating of Cs Br/methanol solution on Cs Pb Br₃ film and its devices was investigated.When the spin coating times of Cs Br is 7 times,the crystallization of Cs Pb Br₃ is the best,and the film formation is the best,and the photoelectric conversion efficiency of corresponding PSCs is 2.96%.Secondly,by introducing mixed green anti-solvent isopropanol IPA and ethyl acetate（1∶1）,the influence of mixed anti-solvent on Cs Pb Br₃ film formation and device was investigated.The photoelectric conversion efficiency of solar cell device assembled by perovskite film prepared by dropping anti-solvent was 4.2%.（3）The film formation of Cs Pb Br₃ was improved by introducing additive PEG with mass fraction of 1%～5%into Pb Br₂ precursor solution.Appropriate amount of PEG can improve the film formation of Cs Pb Br₃.Cs Pb Br₃ prepared with Pb Br₂precursor solution containing 3%PEG has good crystallinity,large size,dense film,few holes and defects,which can make the perovskite absorbent layer more effective contact with the electron transport layer,and better transmission of electrons.The PCE of the corresponding perovskite solar cells reaches 6.5%.This method opens a new idea for preparing perovskite thin films.