| As an emerging photovoltaic technology,perovskite solar cells(PSCs)have attracted much attention due to the impressive photovoltaic performance and simple solution-based fabrication process.Particularly,printable mesoscopic PSCs based on triple-mesoscopic-layer Ti O2/Zr O2/Carbon architecture have shown advantages in stability and upscaling,providing promising prospects for applications.At present,the power conversion efficiency(PCE)of printable mesoscopic PSCs is still lower than that of traditional PSCs,which is mainly due to the low open-circuit voltage.Therefore,this thesis focuses on improving the photovoltage and efficiency of printable mesoscopic PSCs by modifying the interface between electron transport layer and perovskite active layer.The main work is listed as below:(1)Triple-mesoscopic PSCs based on the structure of Ti O2/Zr O2/Carbon by adopting screen printing technique are fabricated.A mixed-cation perovskite of(5-AVA)x(MA)1-xPb I3(5-AVA,5-ammonium valeric acid;MA,methylammonium)containing 3.5%5-AVAI is used as the light absorber.The devices deliver PCE of 13.86±0.34%,VOCof 0.94±0.01 V,JSC of 22.65±0.25 m A/cm2,and FF of 0.65±0.02.These statistical results are used as the control data for device optimization.(2)2-phenylbenzimidazole-5-sulfonate-X(PBS-X,X=Li,Na,K)is introduced to post-treat the triple-mesoscopic structured scaffold.It is found that the conduction band of the mesoporous Ti O2 layer(electron transport layer,ETL)is significantly shifted up,which favors the electron transfer from the perovskite absorber to the ETL,and can effectively inhibit the recombination at the interface of ETL/(5-AVA)x(MA)1-xPb I3.With optimal post-treatment conditions,the champion device delivers a VOC of 1.02 V and an FF of 0.70 with JSC of 23.06 m A/cm2,showing an overall PCE of 16.51%.The PCE and VOCare increased by 13.78%and 8.5%respectively compared with the control devices.(3)The penetration of perovskite precursors in the triple-mesoscopic structured scaffold is investigated.By exploring the relationship between the diffusion distance,diffusion rate and time,a diffusion model is established.This model provides essential data for homogeneously depositing perovskite absorber in large-area mesoporous scaffolds.The viability for deposing perovskite absorber in large-area mesoporous scaffolds by slot-die coating is also evaluated. |
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