| In recent years,silver antimony sulfide（Ag Sb S2）as the absorber layer of photovoltaic materials has attracted the interest of many researchers,due to its good physical properties,such as the characteristics of a suitable energy gap（1.4-1.7e V）,in the near-infrared large absorption coefficient of 104～105cm-1in the range of near IR and visible region,and and the earth-abundant elements that are less expensive than Ga and In.However,due to the immature manufacturing technology and low device performance,the application of Ag Sb S2is very limited.In order to obtain higher photoelectric conversion ability,the most important method nowadays is to improve the quality of the film,and ion substitution is a common method to improve the Ag Sb S2crystal film.Therefore,this thesis uses the ultrasonic spray method to prepare Ag Sb S2thin films with mesoporous morphology,and subsequently uses anion substitution（Se instead of S）to improve the quality of the Ag Sb S2crystal film.The effects of ultrasonic spraying process parameters on the quality of Ag Sb S2films are discussed,and the effects of anion substitution on film morphology,crystal defects,energy band structure and carrier transport properties are focused on.The content specifically includes the following aspects:（1）The Ag Sb S2film was prepared by ultrasonic spray pyrolysis.The single-phase Ag Sb S2film was obtained by controlling the substrate temperature and the ratio of Ag/Sb in the precursor fluid,and the influence of the above process parameters on the optical properties and morphology of the film was discussed.The results show that when the substrate temperature is 350℃,Ag Sb S2single-phase film with mesoporous morphology can be obtained.Combined with the anion substitution method（completed by annealing process）to construct the ITO/Cd S/Ag Sb S2（Se）/Au solar cell structure,it is found that different Ag/Sb ratios have different performance parameters of photovoltaic devices.Among them,when Ag/Sb When=1:1,the photovoltaic device has a stronger light response at 300-600nm,showing better external quantum efficiency.Simultaneously,the AC impedance results also show that the photovoltaic device with Ag/Sb=1:1 has the smallest series resistance（206Ω）and carrier transmission time（7.48ms）,indicating that the device has lower carrier recombination and more effective Charge transfer.The subsequent discussion on the influence of Ag Sb S2film deposition thickness on the photovoltaic performance of the device shows that when the film thickness is 4.5 cycles（about 850nm）,the device exhibits better open circuit voltage and external quantum efficiency.（2）In order to improve the quality of the Ag Sb S2crystal film,the Se element of the same main group as S is selected.The Ag Sb S2film prepared by the ultrasonic spray method is selenized,and the selenization time is optimized to control the content of the film.Compared with the Se concentration（～0.6%）and vacuum treatment（～0.42%）devices,it can be found that the 8min selenization conversion efficiency reaches the best（～1.3%）.The data results show that in terms of energy level matching,the band gap energy level changes from 1.15 e V on the surface to a cascade energy level of 1.68 e V inside the deep layer,which is specifically represented by the Ag Sb S2（Ag Sb S2）next to the Cd S and the Ag Sb S2（Se）gradient next to the Au electrode.The energy band structure of the formula reduces the hole transport barrier between the Au electrode and the Ag Sb S2（Se）absorption layer,and promotes hole transport.In the Hall effect test,the data of vacuum treatment(5.7×1012cm-3)and vulcanization treatment(1.03×1013cm-3)are also compared.As the selenization treatment partially replaces the S element,the carrier concentration is greatly increased(3.31×1018cm-3),the film resistivity of selenization8min is 98.4Ω.cm,the carrier concentration increases and the resistivity decreases,the device performance after selenization treatment shows better short-circuit current（～8.59m A/cm2）,the conversion efficiency of the device is increased from 0.27%of the unannealed treatment to 1.30%.In summary,this thesis uses spray pyrolysis to prepare Ag Sb S2thin films,through anion substitution,a gradient band structure is formed,which effectively improves the photoelectric conversion efficiency of the device,and provides a theory for the photovoltaic characteristics of Ag Sb S2（Se）devices.Support and provide new ideas for the research of AgSbS2... |
