| Perovskite was used in solar cells a decade ago,and the energy efficiency of cells has risen from 3.8 percent to 25.2 percent today.The excellent material properties of perovskite guarantee its great development potential.In the current research,the influence of perovskite solar cell element ratio and electron transport layer?ETL?on device performance has always been a frontier hotspot.In order to understand the perovskite ETL in the role of perovskite solar cells,this study pointed the preparation of the 5 groups of different layers of tin oxide thin film samples,first by contour instrument measured the 5 sample set of concrete thickness,and through the contour curve of instrument can be observed at a layer of film sample surface apparent ups and downs,a layer of samples by microscope in the mulch is not complete,so that a layer of film cannot into thin film samples.Followed by spin coating deposition of the tin oxide prepared by the device,and USES the method of space charge limited current?SCLC?to measure the tin oxide film thickness and defects exist close relationship,the study found that a thin film of unable to present the SCLC curve,this is because the film can't completely cover phenomenon resulted in direct contact with the surface of the ITO electrode.The comparison shows that the defects in the three layers are the least.Followed by atomic force microscopy?AFM?measurement,found that the surface topography of the surface roughness of the film there is a relationship between film thickness and,among them in order to facilitate observation of monolayer film and double film roughness,chose the spin coating film good position measurement,finally came to the conclusion that 5 batch of samples,sample the roughness of the lowest three layers membrane,the surface morphology is the best.In order to understand the influence of film thickness on work function?WF?,the work function of tin oxide film was measured by using the Kelvin probe system,and it was found that the matching effect of work function between the 3-layer tin oxide film and perovskite film was the best.In order to study the effect of the element ratio in the perovskite material on the quality of the film,four groups of ternary cationic perovskite films with a drug ratio were prepared,and XRD diffraction was performed on them.According to the comparison of the peak shapes obtained,the molecular formula was obtained Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 perovskite film has the best crystallization effect.At this time,the ratio of Pb to MA/FA is 0.98:1,and it is observed by AFM It is found that this ratio of perovskite crystal grain size is close to 1 micron,indicating that the crystal quality of the prepared perovskite film is very good.Got the best proportion of perovskite membrane,make use of this ratio,the study in the preparation of the five groups of different thickness of the tin oxide based perovskite solar cells,and by using the standard of the solar cells I-V test conditions,analysis of the photoelectric test 5 samples,according to the test results,we get the samples of 5 groups of series parallel resistance and photoelectric characteristic parameters,such as efficiency,after found tin oxide film thickness and the device has a large connection between efficiency,three layer film corresponding to the highest efficiency of the device was 17.06%,and the layer 1 and layer 2 sample is characterized by low efficiency,this has to do with the tin oxide film quality has the very big relations.The decrease of the efficiency of the 4-layer film and the 5-layer film is mainly due to the deterioration of the resistance performance of the material itself.Therefore,it can be concluded that excessively thin tin oxide film will lead to the decrease of device efficiency due to poor film quality or even failure of film formation,while excessively thick tin oxide film will reduce the performance of the battery due to the increase of film resistance and defects.The optimum film thickness should be 23 nm for a 3-layer film sample. |
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