| China has put forward the strategic goal of "achieving peak carbon in 2030 and carbon neutralization in 2060".Solar photovoltaic will show a doubling trend in the next few decades,and it is an important topic to develop new and high efficiency solar cells.Since the report of 2009,the rapid improvement of PCE has brought new vitality into the field of photovoltaic.The researchers have done a lot of work on the active materials of metal halide perovskite from the aspects of composition control,morphology control,defect passivation,interface modification,and made important progress in theory and technology.PCE of organicinorganic hybrid PSCs has been increased to 25.5%,which is close to crystalline silicon solar cells,which surpasses commercial CIGS and CdTe thin film solar cells.However,organicinorganic hybrid perovskite materials are sensitive to water,oxygen,heat,UV and other environmental factors,which results in poor long-term stability of PSCs devices,which limits the commercialization process.The all-inorganic PSCs can effectively solve the problem of poor environmental stability.The most widely studied is cesium lead perovskite(CsPbX3),in which CsPbBr3(2.3 eV)has superior wet and thermal stability.As a light absorbing layer,CsPbBr3 is expected to form a top cell of laminated battery with silicon solar cells.Indium sulfide(In2S3)is an n-type semiconductor,which has the advantages of high electron mobility,suitable optical band gap(2.0-2.8 eV),good stability,etc.,and can be used as a new type of electronic transmission layer(ETL)material of PSCs.In this paper,the preparation of In2S3 thin film by condensation reflux method is proposed as ETL.Compared with the hydrothermal method reported in the literature,the prepared In2S3 film is compact,uniform and crystal,and has high production efficiency and controllable process.All-inorganic PSC with FTO/In2S3/CsPbBr3/Carbon structure was prepared by optimizing the growth process of CsPbBr3 perovskite crystal by solvent engineering,which is expected to further enhance PCE.The main research work is as follows:In view of the lack of crystallinity of In2S3 thin films prepared by traditional process,In2S3 thin films were prepared by condensation refluxing spin coating process,and the morphology,phase,UV-vis absorption spectrum,band structure and energy level matching of In2S3 thin films were studied.The thickness of In2S3 ETL with different thickness was controlled by adjusting spin coating speed,and the effects of different thickness of In2S3 ETL on CsPbBr3 crystal growth and photovoltaic performance of devices were studied The results show that In2S3 ETL has better energy level matching and electron extraction ability.Finally,PCE,Jsc,Voc and FF are 5.83(4.64)%,6.74(6.81)mA cm-2,1.34(1.29)V and 65(53)%,respectively,for In2S3 ETL based devices,while PCE,Jsc,Voc and FF are 4.99(3.61)%,6.51(5.95)mA cm2,1.24(1.21)V and 62(50)%for TiO2 ETL based devices%The two devices have good stability when placed in air for 720 h at 25?(60?)without package.Aiming at the difficulty of preparing high-purity CsPbBr3 thin films by traditional solution method,the growth of CsPbBr3 thin films was optimized,and the nucleation and crystal growth process was controlled from the perspective of crystallization kinetics.Using low polarity 2-methoxyethanol instead of methanol as the solvent of CsBr,high-quality CsPbBr3 thin films were prepared by solvent engineering.Under the same conditions,PCE increased from 5.83%to 6.42%.By adjusting the condensation reflux temperature(80?,100?,120?,140?)and controlling the aggregation of In2S3 colloidal particles,In2S3 thin films with different surface roughness were prepared,which mainly enhanced the Jsc of the device and further enhanced the PCE to 6.54%.This is mainly due to the smallest surface roughness and stronger electron extraction ability of In2S3 films at 120?. |
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