查找使用阿拉丁产品的科研文献

Air-stable formamidinium/methylammonium mixed lead iodide perovskite integral microcrystals with low trap density and high photo-responsivity

Guangbao Wu,Jiyu Zhou,Rui Meng,Baoda Xue,Huiqiong Zhou,Zhiyong Tang,Yuan Zhang

Here based on integral microcrystal (IMC) thin films of halide perovskites containing formamidinium (FA)/methylammonium (MA) mixed cations, afforded by a facile approach combining an anti-solvent and inverse temperature crystallization, we investigate the impact of the addition of MAPbBr3 on the phase, thermal and environmental stabilities as well as the opto-electronic properties in FA-based IMC films. By single-crystal XRD, FA based IMCs have been found to possess a perfect cubic structure showing a slight lattice contraction compared to pristine FAPbI3 crystals. In conjunction with optical and electrical analyses, the essential role of the introduced MA and Br ions in stabilizing the black phase in FA-based IMCs has been clarified, which explains the observed enhancement of photoluminescence and reduced trap densities. We also achieve stable pure FAPbI3 crystals that do not exhibit a yellow-phase transition after one month in air. By utilizing (FAPbI3)1−x(MAPbBr3)x IMCs as the photo-absorber, we realize highly photo-responsive photodiodes with a satisfactory stability in air and thermal stability upon heating. Of interest, the best photoresponsivity exceeding 300 A W−1 is achieved upon appropriate air-exposure, which is among the highest values reported for FA-based perovskite photodetectors. The air-modified optoelectronic behaviour can be related to the trap passivation through the surface physisorption of the environmental O2, leading to reduced trap densities and resultant harmful SRH recombination.

Visible to Near-Infrared Light Detectors Based on Au/SnS/Ag Schottky Structure With Ultrahigh Responsivity and Fast Response

Biao He,Yongkai Jing,Xinfa Zhu,Chao Fan,Chun Sun,Yonghui Zhang,Mengjun Wang,Hongxing Zheng,Erping Li

In this work, light detectors utilizing p-type tin monosulfide (p-SnS) few layers with an Au/SnS/Ag Schottky structure are demonstrated. These detectors exhibit broad-spectrum light detection capabilities spanning the visible to near-infrared (NIR) wavelength range. Notably, under NIR 850 nm illumination, the detectors exhibit exceptional photodetection performance with an ultrahigh responsivity of up to 1652.87 $\text{A}\cdot \text{W}^{-{1}}$ , an extremely specific detectivity of $8.05\times 10^{{12}}$ cm $\cdot $ Hz $^{\text {1/{2}}}\cdot \text{W}^{-{1}}$ , and a rapid response time of approximately 6.5 ms. These characteristics surpass those of most 2-D materials-based detectors and even outperform commercial InGaAs (Hamamatsu, InGaAs G8370-85) and Silicon (Hamamatsu, Si S9119-01) detectors. The remarkable photoresponse is attributed to the SnS/Ag Schottky structure, which facilitates the separation of excited electron–hole pairs. Our findings suggest a promising route for developing high-performance optoelectronics based on p-SnS.

Self-assembly of positively charged polymer patchy micelles in organic solutions and the reversible ultrasound responsivity of the assemblies

Ya Zhao,Weijing Fan,Hanying Zhao

Self-assembly of asymmetric structures has been attractive for applications in the fabrication of hierarchical structures. However, the role of the electrostatic interaction in the self-assembly of charged asymmetric particles in organic solvents has not been fully understood. In this research, self-assembly of positively charged patchy micelles in organic solutions and the reversible ultrasound responsivity of the assemblies are studied. Surface micelles (s-micelles) with cross-linked/quaternized poly(2-(dimethylamino)ethyl methacrylate) (q-PDMAEMA) cores and poly(oligo(ethylene glycol) monomethyl ether methacrylate) (POEGMA) coronae were prepared on the surfaces of silica particles. Positively charged patchy micelles were synthesized upon cleavage of the s-micelles. In THF, the patchy micelles self-assemble into vesicles with positively charged q-PDMAEMA in the walls and POEGMA in the coronae. The average size of the vesicles is dependent on POEGMA chain length. The repelling electrostatic interaction between the positively charged q-PDMAEMA patches in the walls is unfavorable for the achievement of low free energy of the assemblies, but it is energetically favorable for the vesicles to overcome energy barriers in the dissociation of the structures under ultrasound irradiation. The vesicle structures present reversible ultrasound responsivity. Under sonication the vesicles formed by patchy micelles dissociate into transient nanostructures, including aggregates and isolated patchy micelles. When the ultrasound is switched off, the transient nanostructures self-assemble into vesicles. By contrast, crosslinked vesicles do not show ultrasound responsivity. This research provides a new approach to the fabrication of responsive assemblies based on asymmetric structures, and the assemblies could find potential applications in medicine and bioengineering.

Strain Engineering and Its Mechanism in the Detection of Responsivity to Cu2+ and Pb2+ Based on Two-Dimensional g-C3N4

Feng Lin,He Liu,Yu Tang,Xuejun Zheng,Hui Dong

Two-dimensional (2D) materials are widely used in heavy metal ion detection due to their high specific surface area and abundant active sites. Herein, we prepared highly selective and sensitive electrochemical sensors based on 2D graphitic-phase carbon nitride for the detection of Cu2+ and Pb2+ ions and investigated the effects of both tensile and compressive strains on the corresponding detection sensitivity, together with their mechanism. The prepared carbon nitride nanosheet sensors showed detection sensitivities of 3.63 and 0.41 μA·μM·cm–2, detection ranges of 0.2–100 and 6–100 μM, and detection limits of 0.0033 and 0.23 μM for Cu2+ and Pb2+, respectively. The induced compressive strain of −0.25% in the 2D CNNS significantly improved the sensitivity by 40.5% and 31.7%, while the tensile strain of +0.25% reduced the sensitivity by 41.9% and 43.9% in detecting Cu2+ and Pb2+ as compared to those at zero strain, respectively. Through DFT calculations, the corresponding compressive strain of −0.25% reduced the band gap from 1.21 eV under zero strain to 0.94 eV. On the contrary, the tensile strain of +0.25% increased the band gap from 1.21 to 1.45 eV, resulting from the contribution of orbitals of C-p and N-p. The declined and raised band gaps, respectively, result in increased and decreased electron transport rates, thereby improving and degrading the sensitivities of the sensors. Our research provides guidance on the design of flexible wearable sensors integrated into the construction of sensitive and reliable heavy ion detection systems.

Enabling robust broad-spectrum photodetection with ultra-high responsivity through vapor growth of 2D all-inorganic lead-free Cs2SnI6 perovskites

Jun Xie,Mei Zhao,Youqing Dong,Chao Zou,Shuang Pan,Quanlong Xu,Yun Yang,Shun Wang,Lijie Zhang

The all-inorganic lead-free perovskite Cs 2 SnI 6 has gained considerable research attention due to its outstanding characteristics, including non-toxicity, robust stability, and superior photoelectric performance. In this research, we employed a simple yet robust chemical vapor deposition technique to successfully grow ultra-thin 2D Cs 2 SnI 6 flakes on a mica substrate, achieving a minimal thickness of just 8 nm and a significant lateral size of up to 48 μm. The obtained 2D Cs 2 SnI 6 flakes displayed an extended photoluminescent lifetime of approximately 1.44 ns and exceptional stability, maintaining their crystal structure intact over a period of 60 days. The photodetectors fabricated from Cs 2 SnI 6 flakes demonstrated a broad ultraviolet to near-infrared response range (365–1342 nm), with a responsivity of up to 6.25 × 10 5  A W −1 . They additionally displayed rapid rise and decay times of 31.32 ms and 72.42 ms, respectively, with an external quantum efficiency reaching as high as 1.92 × 10 6 %, and a detectivity achieving 1.27 × 10 11 Jones. This research serves as a critical step forward in enabling the facile yet robust synthesis of stable, all-inorganic ultra-thin lead-free perovskites, paving the way for innovation in environmentally friendly optoelectronic devices.

Micron-Scale Photodetectors Based on One-Dimensional Single-Crystalline Sb2–xSnxSe3 Microrods: Simultaneously Improving Responsivity and Extending Spectral Response Region

Xue Luo,Shuo Chen,Lixiang Liu,Jianhang Lv,Akeel Qadir,Khurram Shehzad,Xvsheng Qiao,Yang Xu,Lorenz Kienle,Andriy Lotnyk,Xianghua Zhang,Guodong Qian,Xianping Fan

Among various one-dimensional (1D) materials, antimony selenide (Sb2Se3) has the large visible to near-infrared (vis–NIR) absorption cross section and excellent stability; thus, it shows a huge potential to be applied as photodetectors. However, low electrical conductivity (10–6 Ω–1·m–1 in bulk state) largely limits the extensive applications of Sb2Se3. By a hot-injection-based Sn/Sb substitution strategy, we prepare 1D Sb2–xSnxSe3 microrods to further improve photodetecting performances of Sb2Se3 microrods. Phase and microstructural analysis revealed the formation of orthorhombic 1D Sb2–xSnxSe3 microrods with the length of 20–30 μm. From Hall effect measurements and absorption spectra, the Sb2–xSnxSe3 microrods were evidenced as a p-type semiconductor with a higher electrical conductivity (6.95 × 10–4 Ω–1·m–1) and a smaller band gap (0.97 eV) compared with Sb2Se3 microrods. Accordingly, the photodetector based on a single Sb2–xSnxSe3 microrod exhibited a remarkable response to 980 nm light at 10 V with a high responsivity (1.84 × 104 A·W–1), a fast response/recovery time (0.134 s/0.153 s), and a long-term durability. Because of the small band gap, the photodetector also exhibited a broadband photoresponse at vis–NIR spectral range. Given their high-responsivity and broadband response, the photodetector based on a single Sb2–xSnxSe3 microrod is a promising candidate for applications in next-generation microdevices.

Albumin-stabilized manganese-based nanocomposites with sensitive tumor microenvironment responsivity and their application for efficient SiRNA delivery in brain tumors

Kai Xu,Zhenghuan Zhao,Junfeng Zhang,Wei Xue,Haipeng Tong,Heng Liu,Weiguo Zhang

Mn(IV)-Based nanoparticles (NPs) are effective in improving tumor oxygenation (hypoxia) and reducing endogenous hydrogen peroxide and acidity in the tumor region. However, the optimized reduction conditions of conventional Mn(IV)-based NPs are generally reported at pH ≤ 6.5, while the usual pH range of the tumor microenvironment (TME) is 6.5–7.0. The dissatisfactory imaging performance in the weakly acidic environment may limit their further application in tumor diagnosis. In this study, Mn(III) was introduced in a nanoplatform, because it is reduced into Mn(II) in weakly acidic environments. Arg-Gly-Asp (RGD) peptide-decorated bovine serum albumin (BSA) was employed as the stabilizer and scaffold to fabricate Mn(III)- and Mn(IV)-integrated nanocomposites (RGD-BMnNPs) with suitable size, good stability, and excellent biocompatibility. The as-prepared NPs showed clear contrast enhancement at pH 6.5–6.9 in vitro as well as sensitive and rapid T1-weighted imaging performance within the tumor region in a glioblastoma (U87MG) orthotopic model, owing to the intrinsic disproportionation reaction of Mn(III) in the weakly acidic environment. In addition, these NPs could be used for efficient siRNA delivery. They showed superior advantages in this process, including increased tumour uptake, improved tumor accumulation and enhanced therapeutic effects with the modulation of the TME. These novel albumin-stabilized manganese-based NPs combined with efficient drug delivery capacity hold great potential to serve as intelligent theranostic agents for further clinical translation.

Preparation of high electromagnetic interference shielding and humidity responsivity composite film through modified Ti3C2Tx MXene cross-linking with sodium alginate

Chenxiang Zhao,Bihua Xia,An Hu,Mingxuan Hou,Ting Li,Shibo Wang,Mingqing Chen,Weifu Dong

This paper established a new kind of L-citrulline-modified MXene cross-linked sodium alginate composite film through solution blending and casting film methods. The L-citrulline-modified MXene cross-linked sodium alginate composite film exhibited high electromagnetic interference shielding efficiency of 70 dB and high tensile strength of 7.9 MPa, which were much higher than the sodium alginate film without L-citrulline-modified MXene. In addition, the L-citrulline-modified MXene cross-linked sodium alginate film appeared humidity responsibility in a water vapor environment, the weight, thickness, and current appeared to increase trend and the resistance appeared to decrease trend after it absorbed water, and these parameters recovered to their original values after drying.

Deep Ultraviolet Photodetector with Ultrahigh Responsivity based on a Nitrogen-Doped Graphene-Modified Polypyrrole/SnO2 Organic/Inorganic p–n Heterojunction

Shihao Fu,Renjing Song,YueFei Wang,Yurui Han,Chong Gao,Jiangang Ma,Haiyang Xu,Bingsheng Li,Aidong Shen,Yichun Liu

Deep ultraviolet monitoring is realized via a high crystal quality SnO 2 microwire (MW)-based photodetector (PD). This is then combined with 2D nitrogen-doped graphene (NGr), conducting polymer polypyrrole (PPy), and an in situ polymerization-fabricated composite film PPy-NGr to construct an organic–inorganic p–n heterojunction PD. The long response time brought on by the oxygen adsorption of SnO 2 MW is greatly decreased via coating with the aforementioned materials. A defect response is created by the surface dangling bonds of SnO 2 MW, which can be effectively suppressed by the PPy. Absorption in the deep ultraviolet region (<240 nm) by PPy results in a blue shift of the response peak of the PPy/SnO 2 heterojunction PD compared to that of a single SnO 2 PD. The introduction of NGr improves the detection performance by providing a smoother energy band migration to reduce photogenerated carrier recombination and stacking at the potential barrier. The ultrahigh responsivity of PPy-NGr/SnO 2 PD is 4594.25 A W −1 and the detectivity is 6.47 × 10 11 Jones, 40 and nine times greater, respectively, than those of a PPy/SnO 2 PD under a 5 V reverse bias and 240-nm light irradiation (18.75 µW cm −2 ). The novel strategy provides a reference for the future design of high-performance heterojunction PDs.

Poly(lactic acid)/poly(ethylene glycol) supramolecular diblock copolymers based on three-fold complementary hydrogen bonds: Synthesis, micellization, and stimuli responsivity

Xiaohua Chang,Chenlei Ma,Guorong Shan,Yongzhong Bao,Pengju Pan

Thymine-terminated poly(lactic acid) (PLA-THY) and diaminotriazine-terminated poly(ethylene glycol) (PEG-DAT) are synthesized and they can form the supramolecular amphiphilic diblock copolymers in solution through the thymine/diaminotriazine complementary hydrogen bonding interactions. Such supramolecular copolymers self-assemble into the stimuli-responsive micelles in aqueous solution. Micelle size, crystalline state, stimuli responsibility, drug loading and release behavior of the supramolecular micelles can be readily tuned from the block length, stereostructure, homo and stereocomplex crystallizations of hydrophobic PLA blocks. The enantiomerically-mixed supramolecular copolymers with both poly( l -lactic acid) (PLLA) and poly( d -lactic acid) (PDLA) blocks assemble into the stereocomplexed micelles, while those having the isotactic PLLA (or PDLA) and atactic poly( d , l -lactic acid) (PDLLA) blocks form the homocrystalline and amorphous micelles, respectively. The stereocomplexed and amorphous micelles exhibit smaller size than their homocrystalline analogs, all of which are much larger than the micelles formed from the conventional covalently-bonded diblock copolymers. The supramolecular micelles are sensitive to the external stimuli such as pH and ion. The homocrystalline and stereocomplexed micelles undergo fast aggregation in the acidic and salted solutions due to the disassociation of complementary hydrogen bonds. The stereocomplexed micelles exhibit larger drug loading content and slower drug release rate than the amorphous and homocrystalline ones, because of the larger polymer/drug interactions and tighter chain packing inside the micelle cores.

High-responsivity and self-powered photoelectrochemical ultraviolet photodetector based on self-supporting SiC/GaN heterojunction nanoarrays for reliable underwater optical communication applications

Runchao Dong,Bartosz Orwat,Beata Luszczynska,Jia Zhang,Hongxin Yin,Genqiang Liu,Weijun Li,Dongdong Zhang,Zhentao Du,Weiyou Yang,Huan He,Fengmei Gao,Shanliang Chen

Controlling the interface properties and surface carrier dynamics of nanostructured semiconductors is crucial for enhancing the electrical and optical performance of photoelectrochemical (PEC) photodetectors (PDs). Herein, a novel self-powered PEC ultraviolet (UV) PD applicable to harsh underwater environments is developed based on integrated self-supporting SiC/GaN heterojunction nanowire arrays. Whole single-crystal integrated self-supporting SiC nanoarrays are encapsulated by high-quality GaN films via two-step anodization and high-temperature nitridation processes. The optimized heterojunction nanoarrays PEC UV PD with 40 min nitridation duration (SiC/GaN-40) demonstrates outstanding photodetection capabilities with high responsivity ( R λ , 698 mA/W), excellent detectivity ( D ⁎ , 1.66 × 10 11 Jones), remarkable external quantum efficiency ( EQE , 231.2 %), and rapid rise/decay times ( τ r / τ d , 127.93/214.92 ms) under 375-nm light illumination at 0.6 V bias voltage. Moreover, the SiC/GaN-40 device demonstrates excellent self-powered performance, achieving exceptional R λ , D ⁎ , EQE, and τ r / τ d , of 588.24 mA/W, 9.3 × 10 10 Jones, 194.9 %, and 160/199 ms, respectively. Furthermore, the device exhibits excellent long-term operational and aging stability even under harsh underwater environments, such as pH-universal and wide-temperature solutions. This study provides a valuable reference for exploring high-responsivity and reliable PEC PDs suitable for harsh underwater optical communication, thus advancing the heterojunction and interfacial engineering strategies for next-generation optoelectronics.

Strong interlayer coupling in p-Te/n-CdSe van der Waals heterojunction for self-powered photodetectors with fast speed and high responsivity

Yanjie Hu,Xiaohui Song,Dongliang Jia,Wanhan Su,Xiaojing Lv,Lin Li,Xueping Li,Yong Yan,Yurong Jiang,Congxin Xia,Congxin Xia