Fluorinated 2D Lead Iodide Perovskite Ferroelectrics

Abstract

electrical transport performance, and long carrier lifetime. Besides these factors, the ferroelectric photovoltaic effect (FEPV) was also believed to contribute to the good performance in PSC. [6] Conventional photovoltaic devices utilize heterojunctions to create asymmetric electric potential to separate the photoinduced charge carriers. While, for FEPV, the photogenerated electron-hole pair is separated by the spontaneous polarization or domain walls in homogeneous ferroelectric materials. [7] Since FEPV is independent to the bending of energy band, it can generate extremely large open-circuit voltage comparable to the bandgap and is expected to enhanced efficiency in PSC. Although FEPV draws a very exciting picture, the ferroelectricity of MAPbI 3 is still controversial. [8] To study the detailed contribution of FEPV in PSC, obtaining a lead-iodide-based polar perovskite materials with settled ferroelectricity is very necessary as a useful complement to the current PSC materials and model system to investigate the role of ferroelectric polarization in photovoltaics.Besides the intensive competition on PCE, PSC are facing a more severe problem of stability. During operation, the applied electric field or optoelectrical field may induce migration of organic molecules and halogen ions. Even without light and electric field, in ambient condition, the moisture and oxygen may also decompose the perovskite. [9] Those factors limit the lifetime of PSC for only ≈1000 h, which is far away from that of conventional silicon-based solar cell panel (20-25 years). One possible solution to this problem is reducing the dimensionality from 3D to quasi-2D, which has large formation energy, high moisture stability, and long lifetime, however, such low-dimensional perovskite will affect transport properties and reduce PCE. [5,10] Until very recently, fluorination on 2D lead iodide perovskite was reported to enhance charge transport and PCE. [11] Thus, in order to achieve a good balance between PCE and stability, a fluorinated 2D lead iodide perovskite ferroelectric material is highly demanded, which is also a good platform to study the fundamental mechanism behind high PCE.Although we have reported several lead-based perovskite ferroelectrics with 2D layered structure, the ferroelectricity can only coexist with chlorine or bromine, even slight doping of iodine would alter the crystal structure and vanish the precious ferroelectric property. [12] Until now, rational design and synthesis of HOIP ferroelectrics is still very challenging and Hybrid perovskite materials are famous for their great application potential in photovoltaics and optoelectronics. Among them, lead-iodide-based perovskites receive great attention because of their good optical absorption ability and excellent electrical transport properties. Although many believe the ferroelectric photovoltaic effect (FEPV) plays a crucial role for the high conversion efficiency, the ferroelectricity in CH 3 NH 3 PbI 3 is still under debate, and obtaining ferroelectric lead i...

Polarization-enhanced photoelectric performance in a molecular ferroelectric hexane-1,6-diammonium pentaiodobismuth (HDA-BiI5)-based solar device

“…[46][47][48] Even in the organic-inorganic hybrid perovskite solar cells, it is very likely that the polarization could be responsible for their outstanding photovoltaic performances. [49][50][51] Thus, aer poling the HDA-BiI 5 lm at different electric elds, the effect of ferroelectric polarization on the photoelectric properties of the (HDA-BiI 5 )-based solar device has been detected under sunlight simulator illumination (Fig. 4).…”

Piezoelectric Energy Harvesting Based on Multiaxial Ferroelectrics by Precise Molecular Design

“…Furthermore, investigations to reveal the domain structure and polarization switching behavior of (TMFM)FeBr 4 , (TMCM)FeBr 4 , (TMBM)FeBr 4 , and (TMIM)FeBr 4 were performed by piezoresponse force microscopy (PFM), which allows identification of the polarization distributions in both vertical (out-of-plane) and lateral (inplane) components. 43 Figure 5 displays the vertical and lateral PFM amplitude and phase images of (TMFM)FeBr 4 thin film. The acquired PFM images show that the domains in as-grown films have an irregular shape.…”

[(C8H17)4N]4[SiW12O40] (TASiW‐12)‐Modified SnO2 Electron Transport Layer for Efficient and Stable Perovskite Solar Cells

“…The performance parameters of the different S‐SnO 2 devices are summarized in Table S1, Supporting Information. Hysteresis is generally regarded as a barrier leading to a misestimated PSC performance and four main types have been identified and widely studied: ion migration, [ 67,68 ] unbalanced charge transport, [ 69,70 ] ferroelectricity, [ 71,72 ] and trap‐assisted charge recombination. [ 73 ] Figure 5d shows the J – V curves of the S‐SnO 2 ‐based device in the forward and reverse scan directions.…”