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Research On Organic Molecule Blending Environment-friendly Anti-solvent Perovskite Solar Cell

Posted on:2020-04-07Degree:MasterType:Thesis
Country:ChinaCandidate:H Y MaoFull Text:PDF
GTID:2432330602458125Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
With the development of society,the demand for energy is increasing continuously.It is urgent for us to find an environmentally friendly energy source to replace traditional fossil fuels.Solar energy is clean and abundant,in which solar cells are the most effective way to utilize solar energy.Since 2009,Perovskite solar cells(PSCs)have attracted extensive attention due to their high conversion efficiency,simple preparation process and low material cost.Perovskite absorption layer is the key layer for the generation and separation of carriers.Improving perovskite absorption layer is one of the most important strategies to improve the performance of perovskite solar cells.The trap states at grain boundary(GBs)of perovskite films lead to charge recombination and perovskite film decomposition,which deteriorate the stability of PSCs.It has been demonstrated that the grain boundary passivation is an effective way to eliminate trap states and enhance the stability of PSCs.Therefore,in this work,we used small organic molecules to passivate the surface grain boundary of perovskite film,reduce the defects at the grain boundary and improve the quality of perovskite film.Thus it can improve the efficiency and stability of PSCs.On this basis,using an environment-friendly solvent partially to replace toxic solvent chlorobenzene as anti-solvent to prepare perovskite film,which could not only coordinate with small organic molecules to control the perovskite crystallization,but also reduce the environmental pollution caused by devices The corresponding work is shown as follows:(1)By using Rubrene mixed with CB as anti-solvent to prepare perovskite film,π bond in rubrene will connect with MA+in CH3NH3PbI3(MAPbI3)making rubrene evenly covered on the surface of perovskite.Thus,rubrene will uniformly cover the surface of perovskite,passivate grain boundary and the defects.It can reduce carrier recombination,facilitate interface contact between perovskite layer and hole transport layer,and thus improve carrier transport performance.Meanwhile,the invasion channels of water molecules are reduced and the hydrophobic properties of the films are improved.By optimizing the addition of rubrene,the power conversion efficiency(PCE)of perovskite solar cell increased from 15.45%to 17.88%,and the stability of the device was also improved significantly.(2)EA and CB mixed with PC61BM was used as anti-solvent to replace pure anti-solvent CB to prepare perovskite film.The mixed morphology of phase separation and heterogeneous junction of CH3NH3PbI3 and PC61BM were used to uniformly cover the surface of perovskite.It can control the grain boundary passivation of perovskite film and reduce the defects and carriers recombination on the GBs effectively.The hydrophobicity of perovskite films can be effectively improved by reducing the invasion channels of water molecules.Meanwhile,PC61BM can also provide an effective transmission channel for electrons and improve the transmission performance of carriers in the interface.Correspondingly,with optimizing the volume ratio of EA/CB,the PCE of perovskite solar cells based on CH3NH3PbI3 increased from 14.4%to 16.1%and the stability is greatly improved.By using environmentally friendly solvent EA to partially replace CB can also reduce the pollution to the human body and the environment.
Keywords/Search Tags:perovskite solar cells, perovskite absorption layer, grain boundary passivation, organic molecules, hydrophobic, stability
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