RSC Advances

Carlier, Thomas; Ferri, Anthony; Saitzek, Sébastien; Huvé, Marielle; Bayart, Alexandre; Da Costa, Antonio; Desfeux, Rachel; Tebano, Antonello

doi: 10.1039/c8ra00824hpmid: 35542786

Artificial [(Nd2Ti2O7)4/(SrTiO3)n]10 superlattices (n = 4 and 8) were successfully epitaxially grown on SrTiO3 substrates by pulsed laser deposition using the in situ high energy electron diffraction reflection diagnostic. The crystallographic relationships between Nd2Ti2O7 (NTO) and SrTiO3 (STO) (layers and substrate) were: [100]NTO//[001]STO, [010]NTO//[1̄10]STO, and (00l)NTO//(110)STO. Nanoscale current variation was detected on both superlattices, with the (NTO4/STO4)10 heterostructure showing a higher density. The (NTO4/STO4)10 sample did not show a piezoelectric response when measured by piezo-force microscopy (PFM), while ambiguous piezoactivity was observed on the (NTO4/STO8)10 superlattice. Scanning transmission electron microscopy energy dispersive spectroscopy analysis showed the diffusion of Nd3+ cations on Sr2+ sites in SrTiO3 structure into the multilayers, which was more pronounced when the value of n was lower. These particular nanoscale electrical behaviors, evidenced by electrical conducting channels and misleading PFM signals, were mainly attributed to the presence of oxygen vacancies in the SrTiO3 layers at higher concentrations near the interface and to the mixed valence state of the titanium (Ti3+/Ti4+). This work showed the strong influence of interface structure on nanoscale electrical phenomena in complex oxide superlattices.

Zhang, Fan; Hu, Yufeng; Lou, Zhidong; Xin, Xige; Zhang, Meng; Hou, Yanbing; Teng, Feng

doi: 10.1039/c7ra13143gpmid: 35542823

The properties of semiconductor/dielectric interfaces are crucial to the performance of polymer field-effect transistors. The key to fabricating high-performance polymer transistors by spin-coating is solving solvent corrosion issues, wherein the solvent of the top polymer produces a rough interface or damage on the underlying polymer layer during deposition. Herein, we propose a mixed-solvent method that employs a mixture of an orthogonal solvent of the underlying polymer and a good solvent of the top polymer as the solvent of the top polymer to prepare polymer bilayers and produce a comparative study of the trap density at the semiconductor/dielectric interface of the corresponding transistor. By changing the ratio of orthogonal solvent to good solvent, namely the degree of orthogonality of the mixed solvent with respect to the underlying polymer, the interface and film qualities of polymer bilayers can be well controlled. We applied this method to spin-coat poly(3-hexylthiophene) (P3HT) on poly(methylmethacrylate) (PMMA) with a mixture of cyclohexane (orthogonal solvent) and chloroform (good solvent). The results of morphology characterizations and electrical property studies indicate the optimal ratio of cyclohexane to chloroform for preparing high-quality P3HT/PMMA bilayers for field-effect conduction is 7 : 3. Transistors based on the optimal bilayers with a bottom-gate/top-contact configuration and a long channel length show good performance. The trap density at the P3HT/PMMA interface is evaluated to be 3.6 × 1012 cm−2 eV−1 from the subthreshold swing, characterizing the distribution of the interface trap levels across the bandgap in P3HT. Furthermore, based on deviations from ideality in the capacitance–voltage characteristics of the metal–insulator–semiconductor capacitor in the device, the traps at the interface are found to be acceptor-type, with the trap density determined to be 2.3 × 1011 cm−2. This value is in a good agreement with that estimated from the subthreshold swing.

Lin, Qingna; Han, Lipeng; Liu, Guoqin; Cheng, Weiwei; Wang, Liqing

doi: 10.1039/c8ra01072bpmid: 35542782

The formation of food-derived glycated phosphatidylethanolamine (PE) in thermal process was investigated by designing a 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE)-glucose model system heated from 40 to 100 °C for 8 h. The main products of glycated PE were determined by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results showed that the glycation of DPPE formed three major glycated compounds: amadori-glycated-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (Amadori-DPPE), carboxymethyl-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (CM-DPPE), and carboxyethyl-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (CE-DPPE). Amadori-DPPE was identified to generate CM-DPPE through oxidative cleavage of glycated polar head group under high temperature and extended incubation time. Additionally, during thermal processing, retro-aldol reactions of glucose led to the formation of two reactive dicarbonyl intermediates: glyoxal (GO) and methylglyoxal (MGO), both of them reacted with amino group of DPPE to form CM-DPPE and CE-DPPE, respectively. Thus, the formation pathways of CM-PE might involve the irreversible rearrangements of Amadori-PE following oxidative cleavage, as well as the glycation of amino group of PE with GO. CE-PE could only be formed by reaction of PE with MGO. Moreover, the content of CM-DPPE was higher than that of CE-DPPE in the same incubation conditions, which indicated that CM-PE might be a more useful predictive marker for food-derived glycated amino-phospholipid, rather than Amadori-PE, particularly in thermal processed foodstuffs.

Duan, Dong; Hao, Chunxi; Shi, Wenyu; Wang, Haiyang; Sun, Zhanbo

doi: 10.1039/c8ra01219apmid: 35542790

A series of Co3O4 catalysts modified by Sm were prepared by a combined dealloying and calcination approach, and the catalytic activities were evaluated using CO catalytic oxidation. The Sm2O3/Co3O4 catalysts were composed of a large number of nanorods and nanosheets, and exhibited a three-dimensional supporting structure with pores. The experimental results revealed that the addition of a small amount of Sm into the precursor AlCo alloy led to a dealloyed sample with improved catalytic activity, and the dealloyed Al90Co9.5Sm0.5 ribbons (0.5 Sm2O3/Co3O4) calcined at 300 °C showed the highest activity for CO oxidation with complete CO conversion at 135 °C, moreover, CO conversion almost no attenuation, even after 70 hours of catalytic oxidation, which is superior to that of Co3O4. The enhanced catalytic activity of the Sm2O3/Co3O4 catalyst can be attributed to the large specific surface area, more reactive oxygen species and Co3+ ion, as well as electronic interactions between Sm and Co.

Matsumura, Kunihiro; Nishikawa, Keisuke; Yoshida, Hiroaki; Doe, Matsumi; Morimoto, Yoshiki

doi: 10.1039/c8ra02011fpmid: 35542821

The efficient formal total synthesis of histrionicotoxin alkaloids was achieved. In this process, two key reactions were used to construct a core 1-azaspiro[5.5]undecane framework common to histrionicotoxins: a mercuric triflate (Hg(OTf)2)-catalyzed cycloisomerization of a linear substrate, which was developed in our laboratory, and a samarium iodide (SmI2)-mediated ring expansion.

Zhang, Shaoan; Hu, Yihua; Chen, Li; Ju, GuiFang; Wang, Tao; Wang, Zhonghua

doi: 10.1039/c8ra90024hpmid: 35544439

Correction for ‘Luminescence properties of the pink emitting persistent phosphor Pr3+-doped La3GaGe5O16’ by Shaoan Zhang et al., RSC Adv., 2015, 5, 37172–37179.

Zhang, Xiaobin; Dai, Chengli; You, Yuanyuan; He, Lizhen; Chen, Tianfeng

doi: 10.1039/c8ra00151kpmid: 35542779

A comprehensive assessment was conducted in this study to examine the antioxidant and antitumor activities of tea extract produced by Tie Guanyin hybridization. Two radical-scavenging systems of assay in vitro, namely ABTS and DPPH assays, were used to investigate the antioxidant activity of the summer tea and autumn tea extract (STE and ATE) derived from the Jin Guanyin. The results indicated that the major active ingredients were catechins, and the theaflavin is rare in the STE and ATE. Moreover, STE and ATE could significantly suppress the growth of human breast cancer cells MDA-MB-231 in a dose-dependent manner, and wrecked the morphology of mitochondria, activated caspase families, leading to the cancer cell death by both apoptosis and cell cycle arrest pathways. Based on the results from an MDA-MB-231 xenograft nude mice model, STE could effectively prevent the tumor formation, and greatly improve the mice immunity and thus improve their living conditions. Taken together, ATE and STE could act as a healthy and prospective substitute for natural antioxidants and a promising prophylactic agent against cancer. This finding provides a great promising nutritional approach to treat diseases related with oxidative stress.

Lim, Ae Ran

doi: 10.1039/c8ra01315bpmid: 35542796

The 1H chemical shifts and the spin-lattice relaxation time, T1ρ, in the rotating frame of (NH4)2ZnX4 (X = Cl, Br) are observed in order to investigate local phenomena related to successive phase transitions. The temperature dependence of T1ρ values for 1H showed a minimum, and the T1ρ values for 1H appeared to be governed by tumbling molecular motions at high temperatures. In addition, 14N NMR spectra are studied in each phase of (NH4)2ZnX4 single crystals in the laboratory frame. The phase transition temperatures strongly affect the 14N number of symmetry related nitrogen centers within the unit cell. The 1H MAS NMR and 14N NMR results are discussed to elucidate the roles of NH4 ions during the phase transitions of (NH4)2ZnX4.

Onishi, Kaito; Oikawa, Kei; Yano, Hiroki; Suzuki, Takeyuki; Obora, Yasushi

doi: 10.1039/c8ra01410hpmid: 35542799

We show that N,N-dimethylformamide-stabilized Pd nanoclusters (NCs) have high catalytic activity in the reaction of substituted 2-iodoanilines with alkynes to give 2,3-disubstituted indoles. This indole synthesis does not require phosphine ligands and proceeds with low Pd catalyst loadings. The Pd NCs were separated from the mixture after the reaction, and recycled at least three times. Transmission electron microscopy images showed that the Pd particle size before the reaction was 1.5–2.5 nm. The particle size after the reaction was 2–3 nm. X-ray photoelectron spectroscopy showed that the binding energy of the Pd NCs before the reaction was 335.0 eV.

Susha, N.; Nandakumar, K.; Nair, Swapna S.

doi: 10.1039/c7ra13116jpmid: 35542820

Development of novel materials for thin film solar cells are gaining significant attention due to their tunable wide bandgap and extensive application potential in flexible energy harvesters. CdS is a known window material for thin film solar cells. Tuning of the photoconductivity of CdS by doping, substitution and grain size tailoring is widely attempted by researchers. Inorganic core/shell structures like CdS/CdSe, CdS/ZnS etc. are other possible candidates with band gap tailorability. However, such attempts are rare in tailoring the photoconductivity by providing an organic shell over the inorganic core. Here the authors synthesised CdS/betanin core/shell structures using wet chemical routes. Spectroscopic studies show that the composite structure is core/shell like, with CdS as the core and betanin (a natural dye), as the outer shell with an average core particle size of 10 nm. The absorption spectra of the composite system show the signature of an additional band in the lower wavelength region and it is redshifted with increase in betanin percentage. The intermediate band observed in the energy of ∼1.75 eV, helps CdS to enhance the rate of absorption. Simultaneous absorbance of lower and higher energy photons from the solar radiation can increase the efficiency of CdS based solar cells. A huge enhancement in conductivity is observed in CdS/betanin composites on illumination with white light due to the transfer of photogenerated electrons from the conduction band of betanin dye to the conduction band of CdS.