Abstract:Engineering the band gap chemically by organic molecules is a powerful tool with which to optimize the properties of inorganic 2D materials. The obtained materials are however still limited by inhomogeneous compositions and properties at nanoscale and small adjustable band gap ranges. To overcome these problems in the traditional exfoliation and then organic modification strategy, an organic modification and then exfoliation strategy was explored in this work for preparing 2D organic metal chalcogenides (OMCs)… Show more
“…Moreover, Ultraviolet photoelectron spectroscopy measurement shows that the Fermi level of PEPI deviate from the middle of the bandgap and is close to the valence band, which indicates that PEPI is P -type semiconductor material (Supplementary Fig. 9 ) 30 . Fig.…”
In terms of strong light-polarization coupling, ferroelectric materials with bulk photovoltaic effects afford a promising avenue for optoelectronic devices. However, due to severe polarization deterioration caused by leakage current of photoexcited carriers, most of ferroelectrics are merely capable of absorbing 8–20% of visible-light spectra. Ferroelectrics with the narrow bandgap (<2.0 eV) are still scarce, hindering their practical applications. Here, we present a lead-iodide hybrid biaxial ferroelectric, (isopentylammonium)2(ethylammonium)2Pb3I10, which shows large spontaneous polarization (~5.2 μC/cm2) and a narrow direct bandgap (~1.80 eV). Particularly, the symmetry breaking of 4/mmmFmm2 species results in its biaxial attributes, which has four equivalent polar directions. Accordingly, exceptional in-plane photovoltaic effects are exploited along the crystallographic [001] and [010] axes directions inside the crystallographic bc-plane. The coupling between ferroelectricity and photovoltaic effects endows great possibility toward self-driven photodetection. This study sheds light on future optoelectronic device applications.
“…Moreover, Ultraviolet photoelectron spectroscopy measurement shows that the Fermi level of PEPI deviate from the middle of the bandgap and is close to the valence band, which indicates that PEPI is P -type semiconductor material (Supplementary Fig. 9 ) 30 . Fig.…”
In terms of strong light-polarization coupling, ferroelectric materials with bulk photovoltaic effects afford a promising avenue for optoelectronic devices. However, due to severe polarization deterioration caused by leakage current of photoexcited carriers, most of ferroelectrics are merely capable of absorbing 8–20% of visible-light spectra. Ferroelectrics with the narrow bandgap (<2.0 eV) are still scarce, hindering their practical applications. Here, we present a lead-iodide hybrid biaxial ferroelectric, (isopentylammonium)2(ethylammonium)2Pb3I10, which shows large spontaneous polarization (~5.2 μC/cm2) and a narrow direct bandgap (~1.80 eV). Particularly, the symmetry breaking of 4/mmmFmm2 species results in its biaxial attributes, which has four equivalent polar directions. Accordingly, exceptional in-plane photovoltaic effects are exploited along the crystallographic [001] and [010] axes directions inside the crystallographic bc-plane. The coupling between ferroelectricity and photovoltaic effects endows great possibility toward self-driven photodetection. This study sheds light on future optoelectronic device applications.
“…DFT simulations were conducted to reveal the crystal structure of two stacked nanoplates in Co-MOF-3, according to SAED diffractions 44 , 45 . The smaller MOF nanoplate, with lattice constants of a = b = 14.3 nm and α = β = γ = 90°, in the nanostacked Co-MOF-3 was named MOF(s), while the crystal structural model of the larger MOF nanoplate, with lattice constants of a = b = 16.4 nm and α = β = γ = 90°, was named MOF(l).…”
Section: Resultsmentioning
confidence: 99%
“…Considering the charge transfer mainly happens at the contact interface, the interfacial electronic structures of monolayer MOF(l) and MOF(s) were investigated using total densities of states (TDOS) (Fig. 2j, k ), respectively 45 . Moreover, the bandgap of 2D MOF(s) and 2D MOF(l) was calculated to be 1.48 and 1.92 eV, respectively.…”
Section: Resultsmentioning
confidence: 99%
“…First, 10 mL of an aqueous solution containing 0.1-M HAuCl 4 and 0.1-M PVP was prepared. Then 0.5 mL of NaBH 4 solution (0.02 M) was added into it at 70 °C 45 . After 1-h reaction, Au NPs were obtained, followed by three times centrifugation/washing using pure water and finally stored in ethanol.…”
Conversion of clean solar energy to chemical fuels is one of the promising and up-and-coming applications of metal–organic frameworks. However, fast recombination of photogenerated charge carriers in these frameworks remains the most significant limitation for their photocatalytic application. Although the construction of homojunctions is a promising solution, it remains very challenging to synthesize them. Herein, we report a well-defined hierarchical homojunction based on metal–organic frameworks via a facile one-pot synthesis route directed by hollow transition metal nanoparticles. The homojunction is enabled by two concentric stacked nanoplates with slightly different crystal phases. The enhanced charge separation in the homojunction was visualized by in-situ surface photovoltage microscopy. Moreover, the as-prepared nanostacks displayed a visible-light-driven carbon dioxide reduction with very high carbon monooxide selectivity, and excellent stability. Our work provides a powerful platform to synthesize capable metal–organic framework complexes and sheds light on the hierarchical structure-function relationships of metal–organic frameworks.
“…The electrical conductivity of 1 was found to be approximately 10000-times higher than those of other crystalline nanotube arrays, and among one of the highest values for crystalline semiconductor materials containing copper or/and chalcogenide elements ( Supplementary Table 4). 6,7,[39][40][41][42] Moreover, the photoconductivity of 1 was investigated. As shown in Fig.…”
The interesting physical and chemical properties of carbon nanotubes (CNTs) have prompted the search for diverse inorganic nanotubes with different compositions to expand the number of available nanotechnology applications. Among these materials, novel crystalline inorganic nanotubes with well-defined structures and uniform sizes are extremely suitable for understanding structure–activity relationships. However, their preparation comes with large synthetic challenges owing to their inherent complexity. Herein, we report the first example of a crystalline nanotube array based on a supertetrahedral chalcogenide cluster, K3[K(Cu2Ge3Se9)(H2O)] (1). To the best of our knowledge, this nanotube array possesses the largest diameter of crystalline inorganic nanotubes reported to date and exhibits an excellent structure-dependent electric conductivity and an oriented photoconductive behavior. This work represents a significant breakthrough both in terms of the structure of cluster-based metal chalcogenides and in the conductivity of crystalline nanotube arrays (i.e. an enhancement of ~ 4 orders of magnitude).
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