Study On Photovoltaic Performance Of Inverted Perovskite Solar Cells Based On Interface Regulation

In recent years,organic-inorganic hybrid perovskite materials have attracted a lot of attention in photovoltaics field due to their excellent photovoltaic properties and simple preparation process.However,the low-temperature solution preparation of perovskite films is prone to excessive defects,leading to severe non-radiative recombination and ion migration,which affects the further enhancement of photovoltaic device performance.Therefore,exploring how to reduce the defects in perovskite films has become an important direction to further improve the performance of perovskite solar cells.In this paper,based on inverted MAPbI₃perovskite solar cells,we analyze the effects of different interface regulation strategies on defect passivation and carrier transport at the top and bottom interfaces of perovskite through top-down sequential tuning,and investigate the mechanism of its device performance enhancement using a combination of experiments and simulations,and the main results are as follows:（1）The photovoltaic performance of inverted MAPbI₃solar cells was simulated using SCAPS to improve the filling factor of the devices by reducing the density of defects at the perovskte/PCBM interface.Dynamic spin-coating of Phenethylammonium bromide（PEABr）on the surface of the perovskite layer to achieve interface regulation demonstrates the interfacial optimization strategy,with PEA⁺diffusing into the perovskite grain boundaries to form 2D/3D perovskite structures during thermal annealing,filling the gaps in the perovskite grain boundaries,effectively passivating the suspension bonds on the perovskite grain boundaries and improving the perovskite/PCBM interfacial contacts.The passivation of interfacial defects effectively suppressed non-radiative recombination and ion migration,and improved charge transfer efficiency,prompting an increase in power conversion efficiency from 17.95%to 19.24%and an increase in fill factor from 72.46%to 78.36%for PEABr-modified devices.In addition,the 2D/3D perovskite structure can effectively hinder the intrusion of water and oxygen,which greatly improves the stability of the device.（2）The growth of perovskite films was regulated by introducing Poly（Ethylene Oxide）（PEO）polymers into the anti-solvent chlorobenzene.PEO acted on the perovskite wet film and triggered non-homogeneous nucleation,forming dense and pinhole-free perovskite films,and reduced the surface roughness of the perovskite films,greatly improving the perovskite/PCBM interfacial contact.A clear fluorescence quenching effect appears from the photoluminescence spectra and time-resolved photoluminescence spectra,indicating that PEO can effectively improve the charge transfer efficiency.At the same time,the ether bond and hydroxyl in PEO can interact with the undercoordinated Pb²⁺and I^-in perovskite,thus passivating the defects at the surface and grain boundaries of the perovskite films and reducing the electron-hole recombination at the perovskite/PCBM interface.The efficiency of the fabricated perovskite solar cells was increased from 16.07%to 19.35%,and the unencapsulated devices maintained 97%of their initial efficiency when stored in a glove box for 1000h.In addition,Silvaco simulation software was used to further analyze the source of the device performance improvement.It was found that the performance improvement was related to the reduction of interface defects and characteristic temperature changes,and the carrier mobility was reduced to compensate for the open-circuit voltage drop caused by the decrease in defect density.（3）By adding a Benzylammonium thiocyanate（BnASCN）bottom interface passivation layer between the PTAA/perovskite layers,the wettability of PTAA was improved and the crystalline growth of the perovskite films was regulated,leading to an increase in the grain size of the perovskite films.the absorption band edges of the BnASCN-modified perovskite films were blueshifted,indicating the formation of a wide band gap of 2D perovskite at the bottom interface,which is conducive to improving the PTAA/perovskite interface and accelerating charge transport.In addition,the measurement of space charge-limited current shows that the defect density of the perovskite film decreases,which is related to the passivation of the formed 2D perovskite and the interaction of the strong electronegative S and N in the pseudo-halogen with the uncoordinated Pb²⁺.The passivation of defects in the perovskite films reduced non-radiative recombination and inhibited ion migration,and the efficiency of the fabricated devices increased from 17.12%to 19.48%,and the BnASCN-modified devices showed almost no decrease in efficiency when stored in a glove box for 20 days.