Quasi-two-dimensional solar cells (2D PSC) have received much attention recently due to their unique optoelectronic properties and device stability. Among 2D perovskite, 2D Dion-Jacobson (DJ) perovskite has a close inter layer distance and does not depend on van der Waals interactions between adjacent spacer cations, which can break the dielectric restriction effect while maintaining its structural stability. Therefore, research interest in 2D DJ PSC is increasing. The polarization effect of electric field change observed in magnetic van der Waals heterostructures was investigated.
However, due to the high formation strength of 2D DJ perovskite, additional help is often required during the crystallization process to obtain the out-of-plane (OOP) crystal structure in a distributed structure, which is necessary to improve transmission plane and prevent radiative non movement.
Recently, a research group led by Professor ZHOU Huiqiong from the National Center for Nanoscience and Technology (NCNST) of the Chinese Academy of Sciences (CAS) conducted a (The polarization effect of electric field change observed) mixed solvent method to study the effect of solvents on the structure of films and device performance. PSC DJ 2D. The study was published online in Nano Letters.
The researchers developed a complex method that directly solves the crystallization process of 2D DJ perovskite by introducing methylamine acetate (MAAc) into the original material with N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Using in situ photoluminescence (PL) and in situ UV-vis absorption spectra, it was found that the nucleation process of perovskite is delayed during the production of the film, which can prevent the nucleation rate of the precursor and support the progress crystals are continuous. Due to the different nucleation rates of the different value systems, the films prepared by the ternary melting scheme achieve a gradient distribution, which is useful for carrier transfer between the systems.
Benefiting from better OOP crystal reconfiguration and gradient distribution, the trap states that 1,5-pentanediammonium (PeDA) based 2D DJ PSCs are very deep (from 0.276-0.510 eV to 0.133- 0.367 eV) and non-radiative accumulation. Energy loss is prevented (from 0.151 eV to 0.126 eV). As a result, the highest open circuit voltage (VOC = 1.25 V) was obtained by the 2D DJ PSC. The device also showed high temperature tolerance, which retains 80% of its original efficiency when used at 85 ° C after 3000 hours.
In situ crystal structure provides a deeper understanding of the mechanisms that control crystallization through solvent effects. This mixed-solvent method may be useful for work focused on perovskite solar cells.
