Critical Thinking

1- visible range (Green), while, Ni doped emission

1-   
Problem
Statement

Spinel
compounds based on Magnesium and aluminum are widely distributed in the earth.
They are comparative cheaper photo catalytic compound but problem being
prepared of MgAl2O4 by using high energy route. Second
problem is to attain high degree of uniform crystallinity/chemical homogeneity.
Transition metal ion doping in Spinel structure is another difficult task to
control its magneto-optical properties.  

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

2-   
Research
Methodology

Magnesium
aluminate spinel (MgAl2O4) doped with transition metal
ions (Mn, Ni, Co and Fe) will be prepared by using Hydrothermal method and
physical evaporation method. First task is to prepare the spinel structure with
the help of hydrothermal method. Afterward, use the spinel powder in physical
evaporation such as chemical vapor deposition method to improve the crystal
quality of spinel structure will be employed. Moreover, physical evaporation
method will be used to dope with transition metal ions. Microstructure of
spinel doped with transition metal ion will be characterized by using optical
tools such as Raman spectroscopy, Photoluminescence and UV absorption spectra.
For structural information Xrd measurement will be used to study the phase
transition under different growth temperature, time and dopant effect. Finally,
VSM will be used to study the magnetic response. Optically active material and
transition metal ion doping make it useful for magneto-optical application.

3-   
Possible
Outcome

Spinel
compound is quite efficient photo-catalyst material and widely used as sensing
material in various areas of research. Transition metal ion doping in Spinel
compound make it suitable for tunable optical application. Mn doped in MgAl2O4
emission spectra is in visible range (Green), while, Ni doped emission spectral
range is in infrared region. Emission intensity and decay life time is the
function of doping ratio that can be observed in spinel microstructures with
the help of optical characterization. Moreover, transparent property of MgAl2O4
is also suitable for solar application.

4-   
present
research work 

Spinel
compound is quite efficient photo-catalyst material and widely used as sensing
material in various areas of research. Transition metal ion doping in Spinel compound
make it suitable for tunable optical application. Mn doped in MgAl2O4
emission spectra is in visible range (Green), while, Ni doped emission spectral
range is in infrared region. Emission intensity and decay life time is the
function of doping ratio that can be observed in spinel microstructures with
the help of optical characterization. Moreover, transparent property of MgAl2O4
is also suitable for solar application.

5-   
Literature
Review

Spinel
structures are important ternary metal oxide crystal structure and also named
as minerals spinel in the form of AIIBIIIO4 (2-3 spinel) or AIVBIIO4 (4-2 spinel). AII+ and AIV+ are divalent
and tetravalent cationsof type I and BIII+ and BII+ are
trivalent and divalentcations of type II. A and B cations with oxygen form two
kind of structuretetrahedral and octahedral which lead the formation of some
intermediate phases. Spinel compounds (AB2O4) are
mostly wide band gap
semiconductor (such as MgAl2O4,
ZnGa2O4, TiZn2O4) and
transparent in visible and IR region which make it
suitable for thin film solar cell, transparent electrode, gas sensors and flat
panel display.

Magnesium Aluminates (MgAl2O4)
naturally exists in crystalline cubic spinel structure. Existence of cationic
disorder (Mg2+ and Al+3) in spinel structure is
distributed between the tetrahedral (Td) and octahedral (Oh)
position. Transition metal ion doping in MgAl2O4 spinel
structure active its optical response and effective useful in photo-catalyst
application. Qiang et al. prepared magnesium aluminates spinel through
co-precipitation method in the presence of different cationic surfactant
solution such as CTAB, Triton X-100 and glucose. Different ratio of listed
cationic surfactant solution can be useful to control the particle size and
surface area 2. Pacurarir et al. prepared the Mg and Al based spinel
structure at low temperature with the help of organic precursor, combustion
method and sol gel method.Nature of precursor, temperature and their ratio are
useful to control the morphology and particle size 3. Different research
groups used different method to prepare spinel structure and explore their
optical behavior. Mn+2 doped in MgAl2O4
emission spectra is in visible range (Green), while, Ni+2 doped
emission spectral range is in infrared region. Emission intensity and decay
life time is the function of doping ratio that can be observed in spinel
microstructures with the help of optical characterization 4-5.

Zinc stannate (ZnSn2O4 also
known as ZTO) is wide band gap spinel compound and suitable for transparent
conducting oxide predominantly used in optoelectronics devices. ZTO
crystallizes in fcc spinel structure, where, Zn+2 (B) ion occupy
tetrahedral voids; B+2 and A+4 ions randomly occupied
octahedral voids. Ali et al. reported that ZTO nanoparticles synthesized via
Hydrothermal method exhibits excellent photo-catalytic properties.
Photodegradation of RhB dye under visible light occurred via two competitive
processes: (i) photo-catalytic process and (ii) photo-sensitized process 6.
Transition metal ion (Mn, Co, Fe) doped in zinc stannate improve the structure,
optical and magnetic properties prepared by physical evaporation and chemical
route. Deng et al. reported the room temperature ferromagnetism of Mn doped ZTO
prepared by chemical vapor deposition. Ferromagnetic coupling indicated thatMn
ion replaced Zn site and exhibits the strong ferromagnetic behavior at room
temperature 7. Sumithra et al. reported the band gap tuning of ZTO cubic
inverse spinel structure by effect of Co doping. Moreover, the dopant
concentration tuned the shape and size of particle; and also exhibits the
strong red shift by increasing dopant concentration. Photoluminescence of ZTO
doped with Mn+2 and Fe+3 confirm the presence of
interstitial defect and oxygen vacancies 8-9. Doping concentration of
transition metal in zinc stannate show magnetization transition from
diamagnetic to ferromagnetic and linear increase in the saturation
magnetization of Fe doping. Such attractive optical and magnetic response made
spinel compounds as suitable candidate for opto-electronics and spintronics
applications.

x

Hi!
I'm Simon!

Would you like to get a custom essay? How about receiving a customized one?

Check it out