ChemPlusChem
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2020
·Vol. 85
·期 1
·240-246
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IF 2.753
Sheng Tang,Xinyu Xiao,Jing Hu,Bo Gao,Hunglin Chen,Zongyang Peng,Jianchun Wen,Masanao Era,Dechun Zou
Graphical Solvent-free is best : Mixed halide hybrid perovskites (MHPs) are prepared through a solvent-free mechanochemical synthesis (MCS) route with superior control over halide compositions. The MCS route eliminates the problem in the preparation of MAPb(I x Br 1− x ) 3 with continuously varying x , while maintaining the material properties and suppressing phase segregation in solvent synthesis (SS) routes. Thus, the optical band gaps can be tuned easily by compositional control. Hybrid perovskites have recently received much attention in optoelectronic applications. However, hybrid perovskites are unstable in a humid environment. Mixed halide perovskites (MHPs) show enhanced stability and band-gap tunability upon engineering of their halide composition. Here, MHPs are prepared through a solvent-free mechanochemical synthesis (MCS) route that allows superior control over halide compositions than the solvent synthesis routes (SS). The MCS route eliminates the problem in the preparation of MAPb(I x Br 1− x ) 3 with continuously varying x , while maintaining the material properties and suppressing phase segregation present in SS routes. UV-vis absorption and X-ray diffraction patterns confirm the production of the desired pure-phase MHPs. For MAPb(I x Br 1− x ) 3 (0≤ x ≤1), with increased ratio of halide ( x ), the cubic phase gradually transforms into the tetragonal phase and band-gap tunability is accomplished. The MCS route for the preparation of MHPs is a very promising and efficient technique for superior control in optoelectronic properties, leading to improved control in fabrication approaches.
研究领域:
材料科学
·
化学
·
光电技术
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
·
2024
·
IF 5.6
Luheng Wang,Maoyuan Nan,Xisi Long
To realize the simultaneous measurement of gap and gas concentration between narrow curved surfaces, in this article, a flexible spiral sensing element based on $\alpha $ -Fe2O3-doped multiwalled carbon nanotubes (MWCNTs) (mass ratio is 100) coated with polytetrafluoroethylene (PTFE) is prepared by spraying and spin coating technology using polyimide (PI) film as the substrate. The spiral structure has eddy current effect under ac excitation, which is sensitive to the change in the gap between the sensing element and metal target. Meanwhile, the $\alpha $ -Fe2O3-doped MWCNTs can respond to gas. The experimental results indicate that the gas response values of impedance amplitude, impedance angle, and resistance are 0.509%, 0.216%, and 1.376% at ethanol vapor concentration of 5000 ppm when the curvature radius is 50 mm with a gap of 0.5 mm, respectively. The absolute/relative sensitivities of impedance amplitude and impedance angle to the gap are 175 $711.54~\pm ~1424.85~\Omega \cdot \text { mm}^{-1}$ /11.347% $\pm ~0.095{\%}\cdot \text { mm}^{-1}$ and $2.614^{\circ }~\pm ~0.015^{\circ }\cdot \text { mm}^{-1}$ /5.307% $\pm ~0.033{\%}\cdot \text { mm}^{-1}$ in the gap range of 0–0.5 mm, respectively. In addition, according to impedance complex plane diagram of the sensing element, a signal processing method based on R–X is proposed, and the ability of flexible spiral sensing element to simultaneously measure the gap and gas concentration between narrow curved surfaces is preliminarily verified.
研究领域:
传感器技术
·
材料科学
·
气体检测
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2018
·
IF 3.235
Yan Zhang,Lingqian Kong,Hongmei Du,Jinsheng Zhao,Yu Xie
Three novel donor-accept type electrochromic polymers with very low band gap, namely PMFTTP, PMFBTTP and PMFMOTTP, were prepared via electrochemical polymerization , employing 2,3-bis(5-methylfuran-2-yl)thieno[3,4- b ]pyrazine as the acceptor units and thiophene , butylthiophen and methoxythiophen as the donor units, respectively. All the polymers were comparatively studied by cyclic voltammetry (CV), scanning electron micrographs (SEM), UV–vis-NIR spectroscopy and colorimetry . The results revealed that PMFTTP and PMFBTTP showed obvious color change from green color to brown in the oxidation process , while PMFMOTTP exhibited color change from brick red to dark gray. And the three polymers possessed very low optical band gaps in the following order: PMFTTP (1.23 eV) > PMFBTTP (0.88 eV) > PMFMOTTP (0.74 eV), which demonstrated the different election-donating ability of thiophene or its derivatives. The electrochromic kinetic investigations manifested that the polymers presented satisfactory optical contrasts (ΔT%) in the near infrared region (NIR), which were 35%, 67% and 60% for PMFTTP, PMFBTTP and PMFMOTTP, respectively. Moreover, the polymers also displayed short switching times (lower than 1 s at any wavelengths), high coloration efficiencies (around about 200 cm 2 /C) and outstanding robust stabilities, suggesting the probability of being the promising candidates for the electrochromic devices. In summary, the above positive results, especially the neutral green color and the very low band gap, had important theoretical significance for the application and development of electrochromic polymers.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Zengxin Pu,Bing Xiao,Siman Mao,Yingxue Sun,Dandan Ma,Hongkang Wang,Jun Zhou,Yonghong Cheng,Jian-Wen Shi
Photocatalytic hydrogen evolution from water splitting presents an attractive prospect in dealing with the energy crisis, but the low efficiency of charge separation and migration still seriously hinders its further practical application. Here, an acidified boron-doped g-C 3 N 4 (HBCNN) and cobalt porphyrin metal organic frameworks (CoPMOF) self-assembled two-dimensional and two-dimensional (2D/2D) hybrid photocatalyst is fabricated successfully. The resultant HBCNN/CoPMOF with optimum ratio exhibits a superior H 2 evolution rate of 33.17 mmol g −1 h −1 , which is 3.04 and 100.50 times higher than the single HBCNN and CoPMOF, respectively. It is found that a coordination connection has formed between CoPMOF and HBCNN through Co-N bond, and the interfacial Co-N bond then forms a pseudo-gap in the up-spin channel of electronic states, establishing an electron-hole separation mechanism. It is this electron-hole separation mechanism that contributes to a Z-scheme transport mode of photogenerated carriers, which greatly promotes the photocatalytic H2 production performance of HBCNN/CoPMOF heterostructure. This work may provide an idea for the design of heterojunction to improve the photocatalytic performance by constructing electron-hole separation through interfacial bond.
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）