Search

Hydroxyapatite (HAP) was co-doped with tellurium and vanadium ions via the co-precipitation method.

The present work pointed out the effect of adding different concentrations of MnO2 (0.25, 0.50, 1.00 and 2.00 wt%) on the structure and crystallization performance of wollastonite glass. Nominal MnO2-containing wollastonite glass was prepared with the addition of 10% Na2O to decrease the melting temperature through melt quenching technique. The thermal history of glasses indicated that the crystallization temperature was between 864 and 895°C. The heat treating of glasses at ∼900 and 1,100°C gave combeite (Na4Ca4Si6O18), rankinite (Ca3Si2O7), pseudowollastonite (Ca3Si3O9), bustamite (CaMnSi2O6) and cristobalite. The later sample densities increased with the incorporation of MnO2 from 1.88 to 2.24 g/cm3 concomitant with decrease of porosities from 32.59 to 20.83%. The microstructure showed nano-size crystals in rounded, angular or irregular micro-size clusters, whereas after soaking in simulated body fluid for 1 month showed submicron crystals of carbonated calcium phosphate phase. Both fourier transform infrared spectroscopy and scanning electron microscopy/energy dispersive X-ray delineated the samples’ biocompatibility. Also, the negative zeta potential results enabled bone cell activity. Moreover, the bone healing with complete mineralization was remarked in case of the in vivo implantation of the G0.50 group. These results can be of a great significance in the application of MnO2-containing combeite, rankinite phases for bone treatment and biomedical applications.

This work reports on the performance of vertical organic field effect transistors (VOFETs) fabricated using two dissimilar dielectric materials, namely poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) and poly(vinylidene fluoride) (PVDF). A comparison of the devices shows that integrating P(VDF-TrFE) enables the VOFET to exhibit significantly higher current of 0.10 mA with mobility of 6.874 × 10−4 m2 V−1 s−1 as compared with PVDF, which has a current of 0.034 mA and mobility equal to 4.24 × 10−5 m2 V−1 s−1. VOFET fabricated with a P(VDF-TrFE) dielectric layer shows a high current, high mobility, substantial ON/OFF ratio and low threshold voltage. The obtained results demonstrate that the VOFET fabricated with P(VDF-TrFE) dielectric layer allows smooth current flow between electrodes and appreciably improves the device characteristics.

In this work, we presented experimental observation on solution-processed bulk heterojunction organic photodiode using vanadyl 2,11,20,29-tetra tert-butyl 2,3 naphthalocyanine (VTTBNc) as a p-type material. VTTBNc is blended with two different acceptors, which are PC61BM and PC71BM, to offer further understanding in evaluating the performance in organic photodiode (OPD). The blend film of VTTBNc:PC71BM with a volumetric ratio of 1:1 exhibits optimized performance in the VTTBNc blend structure with 2.31 × 109 Jones detectivity and 26.11 mA/W responsivity at a −1 V bias. The response and recovery time of VTTBNc:PC71BM were recorded as 241 ms and 310 ms, respectively. The light absorption measurement demonstrated that VTTBNc could extend the light absorption to the near-infrared (NIR) region. The detail of the enhancement of the performance by adding VTTBNc to the blend was further explained in the discussion section.

A novel structured of nanoporous vanadyl 2,11,20,29-Tetra Tert-Butyl 2,3 Naphthalocyanine (VTTBNc) films were prepared by template-assisted method. The structure and morphology of the fabricated VTTBNc nanostructures were studied by field emission scanning electron microscopy (FESEM) and micro-Raman spectroscopy. The VTTBNc nano-porous films showed a potential application in humidity sensors. 2017 Elsevier B.V. We would like to acknowledge University Malaya Research Grant (RP026C-15AFR) and Fundamental Research Grant Scheme (FP046-2015A) for project funding. Appendix A Scopus

In this letter, a p-type organic material from metal phthalocyanine (MPc) derivative, vanadyl 3,10,17,24-tetra-tert-butyl-1,8,15,22-tetrakis (dimethylamino)-29H,31H-phthalocyanine (VTP) has been utilized for fabrication of an organic electronic device. Prior to the fabrication of a vertical organic field effect transistor (VOFET), fundamental work in investigating the energy level of VTP has been done through determination of oxidation and reduction potentials. Energy levels of VTP were calculated based on the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of cyclic voltammetry (CV) and UV–vis analyses. Subsequently, the soluble VTP was employed as an active layer in VOFET with different thicknesses of 90.4 nm, 66.4 nm, and 52.1 nm. It is found that a device with 66.4 nm VTP’s thickness showed the optimum performance, by giving the maximum current density and lowest threshold voltage of around 37 mA/cm2 and 7.1 V, respectively. The effects of the channel thickness on the semi-transparent VOFET devices are explained in this work.

The use of organic materials has become an increasingly important issue in sensing devices in recent times. Phthalocyanine is among the most promising materials in this undertaking. Zinc phthalocyanine (ZnPc) based microporous device was fabricated and its capacitance was utilized as the sensing mechanism for a humidity sensor. The effect of the electrode gap of the device on the electrical properties was investigated along with the correlation between the device’s performances and the morphology of the sensing film. Using the solution-processed spin coating method, the capacitive type humidity sensor devices have been fabricated in a planar geometry of Al/ZnPc/Al with the presence of a microporous template. The size of electrode gaps measured with a surface profiler was 53.00 ± 0.06 μm, 119.00 ± 0.03 μm and 286.00 ± 0.01 μm. The surface morphology was characterized by using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). Analysis of the experimental results showed that the device with the shortest electrode gap (53.00 μm) produced the best sensitivity of 1.03 ± 0.04 pF/%RH than that of the longer gaps. Additionally, hysteresis as well as response and recovery performances have also been investigated.

In the present study, p-type conducting polymer of poly [N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) has been explored for nanostructures. A novel approach has been adopted to transform nanorods into nanotubes by altering template-wetting methods. PCDTBT nanorods are fabricated by infiltrating porous alumina template with various solution concentrations of 5, 10 and 15 mg/ml. Upon thermal annealing PCDTBT beyond its melting point, the nanorods are transformed into nanotubes. The morphological and optical investigations reveal that the nanorods prepared with a concentration of 10 mg/ml are longer, denser, well-arranged and red shifted as compared to other nanorods. The PCDTBT nanotubes of the same concentration prepared at 300 °C are found the best among all other nanotubes with improved length, density and alignment as compared to their nanorod counterparts. Furthermore, the optical spectra of the nanotubes demonstrate broad spectral region, augmented absorption intensity and significant red-shift. The changes observed in Raman shift indicate improvement in molecular arrangement of the nanotubes. Optimization of the solution concentration and annealing temperature leads to improvement of PCDTBT nanostructures. PCDTBT nanotubes, with better molecular arrangement and broad optical spectrum, can be exploited in the state-of-the-art photovoltaic devices. Keywords: PCDTBT, Nanorods, Nanotubes, Template, Polymer melt

Gallium oxide (Ga 2 O 3 ) nanospheres were successfully synthesized via electron beam evaporation of gallium nitride (GaN) pellets on anodic aluminium oxide (AAO) template. Raman analysis proves the formed nanospheres were Ga 2 O 3 with all Raman peaks of the Ga 2 O 3 was present with very good intensities. FESEM analysis proves formation of the Ga 2 O 3 nanospheres on the surface of the alumina template with diameters of around ∼300 nm. Further annealing of the sample eliminates the presence of the nanospheres. Surface roughness analysis via the AFM proved smoother surface was achieved upon higher annealing temperature of 600 and 900 °C. In addition, FESEM analysis of the annealed sample at 600 °C indicates that the nanospheres were empty hollow spheres rather than full-filled nanospheres.

The present study demonstrates a novel nanoporous structure of aluminium 1,8,15,22-tetrakis 29H,31H phthalocyanine chloride (AlPcCl) prepared by template-assisted method for a humidity sensor. The nanoporous sensing layer was fabricated by solution wetting of anodic aluminium oxide template. The solutions of AlPcCl in different concentrations were spun cast over the template at various speeds. Both capacitive and resistive responses were measured as a function of different relative humidity levels. The sensor showed wide operating relative humidity range and responded at quite low humidity levels. Morphological changes were investigated by field emission scanning electron microscopy. The sensor showed wide operating relative humidity range. The sensor demonstrated better performance with improved sensing parameters, highlighting unique advantages of the low-molecular nanostructured sensing layer for the humidity sensors. We acknowledge the University of Malaya for project funding under the University Malaya Research Grant (RP026C-15AFR) and Ministry of Education Malaysia for project funding under the Fundamental Research Grant Scheme (FP046-2015A). This research was financially supported by Hibah Penelitian Dasar Unggulan Perguruan Tinggi No. 385/UN2.R3.1/HKP05.00/2018 from Ministry of Research, Technology and Higher Education Republic of Indonesia. Scopus

In this study, the performance of organic-based photodetectors using poly(3-hexylthiophene) (P3HT) and o-xylenyl-C60-bisadduct (OXCBA) as the donor and acceptor material, respectively, is reported. Four different ratios of 1:0.25, 1:0.50, 1:1.00 and 1:1.50 of P3HT:OXCBA binary blended thin films are used as photoactive layers for organic photodetectors. Optimizing the ratio of photoactive layers dramatically enhances the performance of photodetectors, with rise and decay time of 445 and 309 ms, respectively, are recorded from 1:0.50 ratio. The responsivity of the optimized device is 252.69 mA/W while its specific detectivity is 1.85 × 101°Jones at −1 V, and has shown good stability for over 336 h. External quantum efficiency of 52.77 % and low surface roughness of 0.596 nm are obtained from the 1:0.50 P3HT:OXCBA device. These results imply a high detection potential of P3HT:OXCBA-based photodetector.

This work demonstrates the improvement in photo-current response of poly(3-hexylthiophene) (P3HT)-based thin film organic photodetector by introducing [6,6]-phenyl C71 butyric acid methyl-ester (PC71BM) as an acceptor in binary blended thin films and vanadyl 3,10,17,24-tetra-tert-butyl-1,8,15,22-tetrakis(dimethylamino)-29H,31H-phthalocyanine (VTP) as a complementary holes’ component in ternary blended thin films. The combination of these materials creates favorable energy levels that facilitates the transport of charge carriers from one material to another until it reaches at the respective electrodes. The increase in optical absorption across broader spectral range, the increase in interfacial area and the enhancement in electrical parameters were observed and discussed. In this study, device with ternary P3HT:PC71BM:VTP blended thin films with ratio of 1:1:1 shown the best photo-current response (at 1 V), in which the increase in short-circuit photocurrent density (Jsc) (6.0 mA/cm2) is 78% higher than that of P3HT:PC71BM:VTP with ratio of 1:1:2. The Jsc of ternary blended thin film device (1:1:1) is 5 times higher than that of single material device and it appeared to be 58% higher than that of binary P3HT:PC71BM devices. The increase electrical parameters indicated a significant enhancement in photo-current with the introduction of ternary blended thin films organic photodetector that constitutes of well-matched materials based on their individual optical, morphological and electrical properties.

In this study, low-bandgap polymer poly{[4,4-bis(2-ethylhexyl)-cyclopenta-(2,1-b;3,4-b′)dithiophen]-2,6-diyl-alt-(2,1,3-benzothiadiazole)−4,7-diyl} (PCPDTBT) nanostructures have been synthesized via a hard nanoporous alumina template of centrifugal process. Centrifuge has been used to infiltrate the PCPDTBT solution into the nanoporous alumina by varying the rotational speeds. The rotational speed of centrifuge is directly proportional to the infiltration force that penetrates into the nanochannels of the template. By varying the rotational speed of centrifuge, different types of PCPDTBT nanostructures are procured. Infiltration force created during the centrifugal process has been found a dominant factor in tuning the morphological, optical, and structural properties of PCPDTBT nanostructures. The field emission scanning electron microscopy (FESEM) images proved the formation of nanotubes and nanowires. The energy-dispersive X-ray spectroscope (EDX) analysis showed that the nanostructures were composed of PCPDTBT with complete dissolution of the template.