Study On The Interface Engineering Of Perovskite/Organic Bulk Heterojunction Integrated Photovoltaic Devices

Energy is essential for the development of human society.Perovskite solar cells（PSCs）have attracted extensive attention due to their excellent optoelectronic properties.In recent years,benefiting from the composition regulation,interface optimization and device structure optimization,the power conversion efficiencies（PCE）of perovskite solar cells have increased from 3.8%to 25.7%.The light absorption edge of typical perovskites is generally around 800 nm,but the photon in the near-infrared region（NIR）is not effectively utilized,which restricts the improvement of device performance.By constructing a narrow-bandgap organic heterojunction（BHJ）,the new structure of perovskite/BHJ integrated device can effectively extend the spectral utilization range to the near-infrared region,which is an important feasible method to further improve the device performance.However,compared with pure perovskite solar cells,the open circuit voltage and fill factor of perovskite/BHJ integrated devices are reduced,which indicates the hindered carrier transport or interface charge recombination.Therefore,exploring the interface properties of perovskite/BHJ integrated devices becomes the key to improve the photovoltaic performance of the devices.The specific research contents are shown as follows:1.Regarding the weak conductivity of NiO_x hole transport layer commonly used in devices and the blocked interfacial charge transport,the oxidizing metal ions Fe³⁺and Cr⁶⁺doped in NiO_x to change the ratio of Ni³⁺/Ni²⁺,which can not only improve the film formation and conductivity,but also effectively reduce the work function of NiO_x.Under the condition of doping 0.5%molar ratio,the highest PCE of the device exceeds 17%.2.The interfacial properties of perovskite/BHJ were explored,and it was proved that charge recombination exists at the perovskite/BHJ interface.The ultrathin wide-bandgap semiconductor BCP and Zr Acac were used as interface modification layers to suppress the interfacial charge recombination of perovskite/BHJ.After using BCP and Zr Acac,the work function of the perovskite film was reduced,which enhanced the built-in electric field between the perovskite and BHJ,and effectively reduced the defect state at the perovskite/BHJ interface.Benefiting from the enhanced transport and extraction of interfacial carriers,the PCE of the integrated device exceeds 19%,and the stability of the device is greatly improved,with 80%of the PCE stored in the atmospheric environment for 20 days.This work provides a feasible strategy for perovskite/BHJ interface engineering,which is expected to further improve the performance of integrated devices.