Metal ion mediated mesomorphism and thin film behaviour of amphitropic tetraazaporphyrin complexes

2001 ◽  
Vol 11 (6) ◽  
pp. 1576-1584 ◽  
Author(s):  
S. Holger Eichhorn ◽  
Duncan W. Bruce ◽  
Daniel Guillon ◽  
Jean­Louis Gallani ◽  
Thomas Fischer ◽  
...  
Keyword(s):  
2013 ◽  
Vol 764 ◽  
pp. 266-283 ◽  
Author(s):  
Ibram Ganesh ◽  
Rekha Dom ◽  
P.H. Borse ◽  
Ibram Annapoorna ◽  
G. Padmanabham ◽  
...  

Different amounts of Fe, Co, Ni and Cu-doped TiO2 thin films were prepared on fluorine doped tin oxide (FTO) coated soda-lime glass substrates by following a conventional sol-gel dip-coating technique followed by heat treatment at 550 and 600°C for 30 min. These thin films were characterized for photo-current, chronoamperometry and band-gap energy values. The chemical compositions of metals-doped TiO2 thin films on FTO glass substrates were confirmed by XPS spectroscopic study. The metal-ions doped TiO2 thin films had a thickness of <200 nm="" optical="" transparency="" of="">80%, band-gap energy of >3.6 eV, and a direct band-to-band energy transition. The photoelectrochemical (PEC) studies revealed that all the metal-ions doped TiO2 thin films exhibit n-type semi-conducting behavior with a quite stable chronoamperometry and photo-currents that increase with the increase of applied voltage but decrease with the dopant metal-ion concentration in the thin film. Furthermore, these thin films exhibited flat-band potentials amenable to water oxidation reaction in a PEC cell. The 0.5 wt.% Cu-doped TiO2 thin film electrode exhibited an highest incident photon-to-current conversion efficiency (IPCE) of about 21%.


2021 ◽  
Vol 14 (02) ◽  
pp. 2151012
Author(s):  
Natangue Heita Shafudah ◽  
Hiroki Nagai ◽  
Mitsunobu Sato

Cubic or tetragonal zirconia thin films of transparent and 100 nm thickness were selectively formed on a quartz glass substrate by heat-treating the molecular precursor films involving Zr(IV) complexes of nitrilotriacetic acid, at 500[Formula: see text]C in air for 1 h. A precursor solution was prepared by a reaction of the ligand and zirconium tetrabutoxide in alcohol under the presence of butylamine. By the addition of H2O2 or H2O into the solution, the spin-coated precursor films were converted to cubic zirconia thin films by the abovementioned procedure. Further, the identical phase was produced also in the case of the electro-sprayed precursor film which was formed by an addition of H2O2 into the solution. On the other hand, the tetragonal zirconia thin film was obtained from a precursor film formed by using a solution dissolving the original Zr(IV) complex of the ligand, without H2O2 nor H2O. The crystal structure of all thin films was determined by using both the X-ray diffraction (XRD) patterns and Raman spectra. Thus, the zirconia thin films of both crystals could be facilely and selectively obtained with no use of hetero-metal ion stabilizers. The XPS spectra of the thin films show that the O/Zr ratio of the cubic phase is 1.37 and slightly larger than tetragonal one (1.29), and also demonstrate that the nitrogen atoms, which may contribute to stabilize these metastable phases at room temperature, of about 5−7 atomic% was remained in the resultant thin films. The adhesion strengths of cubic zirconia thin film onto the quartz glass substrate was 68 MPa and larger than that of tetragonal one, when the precursor films were formed via a spin coating process. The optical and surface properties of the thin films were also examined in relation to the crystal systems.


Molekul ◽  
2009 ◽  
Vol 4 (1) ◽  
pp. 6
Author(s):  
Kapti Riyani ◽  
Tien Setyaningtyas

TiO2­ photocatalyst can be used to reduce heavy metal ions into common metal ion or metal ion with lower coordination number. This research aimed to (1) study the influence of pH on the photoreduction activity of Pb2+ion by TiO2­, (2) study the influence of hole scavenger on the photoreduction activity of Pb2+ ion by TiO2­, (3) study the influence of light source on the photoreduction activity of Pb2+ ion by TiO2­. The method used on this research is laboratory experiment consist of the making of TiO2 thin film, standard Pb2+ photoreduction with the variation of pH, standard Pb2+ photoreduction with the variation of light source. The results of Pb2+ photoreduction are analyzed by Atomic Absorption Spectroscopy. The result of the research showed that the activity of TiO2 to reduce Pb2+ can be optimum at pH 6, oxalic acid as hole scavenger and UV lamp use. The sunlight can also be used as the light source to reduce Pb2+ by TiO2 photocatalyst.


1992 ◽  
Vol 53 (3) ◽  
pp. 289-292 ◽  
Author(s):  
S.F. Belykh ◽  
R.N. Evtukhov ◽  
U.Kh. Rasulev ◽  
I.V. Redina

2006 ◽  
Vol 957 ◽  
Author(s):  
Shubra Singh ◽  
N Rama ◽  
M.S. Ramachandra Rao

ABSTRACTThe effect of doping of transition metal ions (Fe and Co) on transport properties of ZnO has been studied in both bulk and thin films. The solubility limit of these ions have been found to be higher in thin films compared to bulk. Optical measurements reveal the presence of Fe in both 2+ and 3+ state. Co is believed to be in 2+ states. Electrical resistivity measurements show that while for bulk Fe doped ZnO samples there is a decrease in resistivity compared to undoped ZnO, it increases for bulk Co doped ZnO samples. However, thin film samples of both types of doped compounds show a decrease in resistivity compared to undoped ZnO. This difference in bulk and thin film behaviour has been explained on the basis of experimental results.


2013 ◽  
Vol 13 (6) ◽  
pp. 2459-2465 ◽  
Author(s):  
Chi-Hsien Huang ◽  
I.-Shun Wang ◽  
Kuan-I. Ho ◽  
Yi-Ting Lin ◽  
Chien Chou ◽  
...  

2020 ◽  
Vol 20 (11) ◽  
pp. 7130-7134
Author(s):  
Seong Gwan Shin ◽  
Hyung Wook Choi

Over the past three decades, the development of renewable energy technologies has attracted significant attention to overcome both environmental pollution and global warming. Recently, a new type of solar cell based on an organic–inorganic halide perovskite material has been developed. Perovskite solar cells (PSC) were first reported in 2009; their efficiencies increased rapidly from 3.8% to 22%. PSCs have many advantages owing to their use of simple processing technology and stable materials. Perovskite materials have a general formula of ABX, where A is generally methyl ammonium CH3NH3+ (MA), B is a metal ion, such as Pb or Sn, and × represents a halogen ion. A distinct advantage of lead-based perovskites (i.e., MAPbX3) is that their band gaps can be easily tuned, from 1.2 to 2.3 eV, by varying their compositions and anions. Titanium dioxide is as often used as an electron transport layer due to its high chemical and optical stability, non-toxicity, low cost, and resistance to corrosion. TiO2 films can be characterized by the defects in their preparation, such as density fluctuations, pinholes, and cracks; these defects can reduce electrical conductivity and cause recombination. In this study, we have demonstrated that the electrical conductivity of TiO2 thin films is improved by its doping with Al3+. When applied to a PSC, the doped thin film improves the charge transfer of the solar cell and increases its efficiency. Our results suggest that Al3+ nanoparticles in the TiO2 layer may contribute to the improvement of the PSC.


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