| Quantum dot-sensitized solar cells(QDSSCs)have received much attention due to their tailored light-harvesting range,solution-deposition processing,and low cost.In the QDSSCs,the porous film of photoanode govern the adsorption of the quantum dots and the transport of the photoelectron.The interface manipulation is generally used in the porous film to increase the absorbed quantum dots and reduce the trap states,which can affect the power conversion efficiency(PCE)of QDSSCs.Nevertheless,the interface manipulation strategy is limited and introduced to the new issues of the porous film,such as poor chemical controllability,structure defect.The novel,stable,and effective interface manipulation strategy plays a crucial role in the performance enhancement of QDSSCs.To address these problems,the regulation chemical ratio of seed layer,the noncorrosive necking treatment of passivating layer,and the distensible pore strategy of novel materials are studied to take to optimizing the interface manipulation on the porous film.The pointed researches are as follows:1.Sol-gel method was used to construct the stoichiometric CdS seed layer.The CdS plays an important role as the seed layer and energy barrier in photovoltaic performance enhancement of CdSe QDSSCs.However,the CdS(CdS-CBD)seed layer is generally synthesized by the chemical bath deposition method(CBD)and suffers from excessive Cd due to the poor controllability of interfacial chemical reactions.Here,we employed a novel sol-gel method to prepare a CdS seed layer(CdS-SG)with a stoichiometric ratio of Cd to S.The results revealed that the stoichiometric CdS-SG seed layer significantly reduced the charge recombination and prolonged the lifetime of photogenerated electrons.The PCE of CdS-SG QDSSCs was almost 28%higher compared to that of reference CdS-CBD QDSSCs.2.Common ion effect was employed to achieve noncorrosive necking treatment of the BaSnO3 porous film.The BaSnO3 is regarded as a promising porous film material because of the high electrical mobility and inferior UV-stimulated photochemical activity.The often-adopted necking strategy involves the treatment in TiCl4 solution with low pH,which can lead to the leaching of Ba2+from BaSnO3 and increase the charge recombination results from trap states.To address this issue,we report herein a novel noncorrosive necking strategy based on the common ion effect.The strategy involved treating the BaSnO3 porous film with a mixture solution of TiCl4 and BaCl2.The TiC14-BaCl2 treatment not only formed the TiO2 passivating layer,but also suppressed the leaching of Ba2+from BaSnO3.The photoelectrical measurements showed that the BaSnO3 porous film with TiCl4-BaCl2 treatment contained fewer trap states and exhibited longer electron lifetime than those based on the BaSnO3 porous film with TiCl4 treatment.Cells with TiCl4-BaCl2 treatment showed ca.37%increase in PCE in comparison with that of reference TiCl4 treatment cell.3.A distensible pore strategy for the photovoltaic performance enhancement of BaSnO3 porous film-based QDSSCs.BaSnO3 nanoparticles were commonly prepared by coprecipitation method and presented high crystallinity.Nevertheless,the BaSnO3 nanoparticles prepared with this method were inducing the small diameter(10～20 nm)and difficult mixing them with organic pore-introducing agent(ethyl cellulose).This leads to small pores of BaSnO3 porous film,which hindered the penetration of electrolyte and deposition of quantum dot.To solve this problem,large-size SnO2 nanoparticles(50～70 nm)were induced as pore-distending agent to prepare a SnO2-BaSnO3 porous film.The added SnO2 nanoparticles efficiently increased average pore diameter of BaSnO3 porous film by ca.75%.The electron transmission measurements revealed that the SnO2-BaSnO3 porous film significantly reduced the charge recombination and increased the charge collection efficiency.The SnO2-BaSnO3 porous film-based QDSSCs showed ca.11%increase in PCE than that of reference BaSnO3 porous film-based QDSSCs. |
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