CSPBI3 perovskites have attracted great attention in photovoltaic applications due to their ideal bandgap and good thermal stability. However, due to the severe interfacial energy loss inside CSPBI3 perovskite solar cells (PSCs), there is an obvious problem of insufficient photovoltage in PSCs, which greatly affects the photovoltaic performance of PSCs.
March 4, 2024, Beijing University of Aeronautics and AstronauticsZhang XiaoliangThe team of professors is inangewThe journal was published with the title "Dipolar Chemical Bridge Induced CSPBI3 Perovskite Solar Cells with 21".86% efficiency", team membersjunming qiuHe is the first author, and Professor Zhang Xiaoliang is the corresponding author.
In this study, a dipole chemical bridge (DCB) was constructed between the perovskite layer and the TiO2 layer to reduce the interfacial energy loss and thus improve the charge extraction of PSCs. The results show that DCB can form a favorable interfacial dipole between the perovskite layer and the TiO2 layer, thereby optimizing the interfacial energy of the perovskite TiO2 layer and improving the energy level arrangement inside the PSCS. At the same time, the constructed DCB can also passivate the surface defects of the perovskite and TiO2 layers at the same time, which greatly reduces the interfacial recombination. Therefore, the problem of insufficient photovoltage of PSCS was alleviated, and 21Record efficiency of 86%. At the same time, the operational stability of PSCS is also significantly improved due to the high-quality perovskite thin film obtained after the formation of DCB in the PSCS, which releases the interfacial tensile strain.
The researchers used 4-aminobutyric acid (Ca) and 3-amino-1-propanesulfonic acid (SA) molecules to construct a viable bipolar chemical bridge (DCB) between the perovskite and TiO2 layers, thereby greatly reducing the interfacial energy loss of PSCs. Based on theoretical calculations and experimental studies, the interface functionalization of perovskite TiO2 and its influence on the operation of PSCS devices are clarified. The results show that SA can strongly anchor the surface of TiO2 and coordinate with the perovskite, so that the defects on the surface of TiO2 and the bottom surface of the perovskite film can be passivated at the same time, and the charge recombination can be inhibited. In addition, a beneficial interfacial dipole is formed at the perovskite TiO2 interface, which facilitates electron extraction at the interface. Therefore, thanks to the significant reduction in interfacial energy loss, the PCE of DCB-based PSCS is as high as 2186% with a VOC of 1At 26 V, it is the most efficient CSPBI3 PSCS available.
In conclusion, a novel and feasible DCB was constructed in PSCS to reduce the interfacial energy loss, so that PSCS has high photovoltaic performance and stability. Functional SA molecules can be firmly anchored to the surface of TiO2 and chemically bonded to the [PBI6]4-octahedral framework of perovskite, thereby improving the interfacial tensile strain at the perovskite TiO2 interface and promoting the transport of charge carriers at the interface. At the same time, SA can also improve the crystallinity of perovskites by mitigating the interfacial lattice distortion, thereby significantly reducing non-radiative recombination. As a result, the efficiency of the SA-based PSCS reached a record 2186%, and the stability of the device is also greatly improved. The reason for the improved performance of SA-based PSCs may be that the interfacial energy loss at the perovskite TiO2 interface is greatly reduced. This work provides an important principle for the interface functionalization of PSCS by dipole chemical bridging method, and also provides a new way to construct high-performance PSCS or other perovskite optoelectronic devices.