| As one of the main forces of new photovoltaic technology,perovskite solar cells(PSCs)have a flexible spectral response range in the visible-near infrared wavelength band,strong light absorption ability and good low light effect,compatibility with solution processing and other characteristics,thus enabling a wide range of prospects for application in the field of flexible photovoltaic devices,mobile wearable devices and so on.Although PSCs can rival conventional silicon-based PVs in terms of efficiency,the inherent instability under long-term operating conditions remains a serious challenge to their commercialization.Constructing a low-dimensional perovskite structure by introducing large spacer cations can effectively improve the integrated stability of the crystalline material,while the irregularly oriented quantum well structures with different widths that can be spontaneously formed.This process leads to excessive exciton binding energy and energy losses,which would limit the device performance.The development of large spacer cationic species and regulated crystal growth have provided opportunities to study and optimize the carrier transport properties of highly efficient low-dimensional PSCs.However,the vast majority of optimization strategies have been validated in the spin-coating process,and further studies on large-area low-dimensional PSCs based on the printing process remain elusive due to the variability of the film formation process.This paper addresses the unclear crystallization regularity of low-dimensional perovskite crystals,poor film homogeneity and difficult compatibility with printing processes.Focusing on the interaction mechanism of large spacer cations involved in the formation of quantum well structures,we realize highly efficient,stable and reproducible low-dimensional perovskite devices and their module fabrication by exploring the molecular configuration differences,colloidal self-assembling behaviors,and repairing the humidity-induced interfacial degradation in air.The specific studies are as follows:1.Three phenylammonium compounds with different alkyl chain lengths were introduced as large spacer cations to construct lattice-reinforced structures on the surface of three-dimensional perovskite films,and the differences in molecular configuration were used to regulate the hydrogen bonding and van der Waals interactions between the large spacer cations and inorganic octahedral skeletons,so as to establish an intrinsic relationship between the lattice distortion,interfacial low-dimensional structures formation,and the release of residual stresses.It is demonstrated that the target devices based on the lattice reinforcement strategy exhibit champion photoelectric conversion efficiency(PCE)of 22.90%and suppress the multi-path phase transition process under various environments.In addition,a mini-module with a PCE of 17.10%was prepared on a 25 cm~2 substrate,which validated the feasibility of large-area printing fabrication.2.To address the limitations of surface-constructed lattice-reinforced structures in improving stability,the colloidal assembly behavior in precursor solution was modulated to induce intermediate-phase structures,enabling printing fabrication of efficient bulk low-dimensional PSCs.The assembly behavior of organic cations in the lead iodide-dominated colloidal soft framework was visualized by exploring species differences in precursor solutions under hydrogen bonding interactions.The significantly suppressed multiple quantum well distribution in pure formamidine low-dimensional perovskite films was verified,and the corresponding small-area devices(n=9)had a PCE of 20.28%and maintained an initial efficiency of 91%after 1500 h of storage in air at 40-50%relative humidity.In addition,the mini-module with a PCE of 15.35%was printed in air,suggesting that the colloidal assembly strategy is instructive for the printing fabrication of large-area low-dimensional PSCs.3.In order to further improve the device performance of printed low-dimensional perovskite photovoltaics,alternating-cation interlayer(ACI)perovskites capable of reducing the van der Waals gap were selected for this study.Due to the moisture sensitivity of guanidinium cations,adsorbed water was utilized as a nucleation medium for atomic layer deposition to repair humidity-induced interfacial degradation in the air,while expanding the humidity processing window for scalable ACI PSCs.The PCE of the target device(n=5)was 21.0%and 19.7%at an effective area of 0.09 cm~2 and 1.01 cm~2,respectively,which is one of the highest PCE in large-area low-dimensional perovskite photovoltaics.The target device maintained an initial efficiency of 93%after 170 days(4080 hours)of storage in an air environment.Subsequently,the scalability of the strategy was verified on an ACI perovskite module with 100 cm~2 substrate area. |
