ppt file of M.Sc. research

1. A DFT Study on Pure and Transition Metals (Ti, Zr, Hf) Doped
Boron Nanoclusters (B6 and B8) to Explore the Structural,
Electrical and Optical Properties
Presented By
Abdullah Faiaz Alfi
Exam Roll No : 21712010
Registration No : 21712010
Session (M.Sc.) : 2016-17
Supervised By
Dr. Sajal Chandra Mazumdar
Associate Professor
Department of Physics
Comilla University

2. Outline
◙ Nanomaterials
◙ Aim of the Study
◙ Computational Techniques
◙ Results and Discussions
◙ Conclusions
◙ Future Aspects
◙ References

3. What are Nanomaterials?
◙ Single unit size of materials
are called nanomaterials
◙ Size range basically 1-100 nm
◙ Classified by four types
namely 0D, 1D, 2D and 3D
◙ Among them 2D
nanomaterials are most
promising Fig 1: Dimension based classification of
nanomaterials, Zero dimension, One dimension,
two dimension and Three dimension .

4. Why 2D Nanomaterials ?
◙ Atomic growth is possible in two direction only
◙ Large surface to volume ratio
◙ The novel properties: structural, electrical,
optical Surface Plasmon Resonance (SPR),
exceptional anisotropy and chemical
functionality
◙ Graphene the first 2D nanomaterial discovery of
by K. Novoselov and co-workers in 2004
◙ Borophene was the starting 2D nanomaterial in
the current study
Fig 2: Schematic illustration of
graphene nanosheet .

5. Borophene as 2D Nanomaterial
◙ 2D boron allotrope are called borophene
◙ The proposed unit of borophene
consisting of 36 boron atoms
◙ Boron atoms are electron deficient
◙ Different shapes of vacancies
◙ These vacancies are very crucial for
tuning the properties of any boron clusters
◙ Various doping based computational works
has been done to see different properties
and applications
Fig 3: Illustration of quasi-planar
and planar borophene

6. Aim of the Study
Pyramidal Shape
◙Structural properties
◙Electrical properties
◙Optical properties

7. Computational Techniques Why DFT?
 Computational quantum mechanical modelling method
 To investigate the electronic structure.
 The geometry optimization was done using DFT method.
 Advantages of DFT:
 Low computation cost
 Give accurate result within a short period of time
 Electron density is the only variable
 Deviation is very little with experiments

8. Computational Techniques Basis Sets
 Describe the possible positions of an electron in an atomic or
molecular system
 Transforms SE and SE like differential equations into
algebraic equations
 Popular basis sets: STO-3G, 3-21G, 6-31G, SDD and
LANL2DZ for gaseous molecules
 In the current work we used SDD and B3LYP

9. Results & Discussions Geometrical Stability Analysis
TiB6(-4.08eV) HfB6(-4.35eV) ZrB6 (-8.97eV)
Here calculated adsorption energy for doped structures are high
enough which show the great structural stability of the optimized
structures
Mulliken charge indicator

10. Results & Discussions Geometrical Stability Analysis
TiB6(-4.08eV) HfB6(-4.35eV) ZrB6 (-8.97eV)
Here calculated adsorption energy for doped structures are high
enough which show the great structural stability of the optimized
structures
Mulliken charge indicator

11. Results & Discussions Geometrical Stability Analysis
ZrB8(-6.08eV) HfB8(-11.96eV) TiB8 (-12.78 eV)
Here calculated adsorption energy for doped structures are high
enough which show the great structural stability of the optimized
structures
Mulliken charge indicator

12. Results & Discussions Geometrical Stability Analysis
ZrB8(-6.08eV) HfB8(-11.96eV) TiB8 (-12.78 eV)
Here calculated adsorption energy for doped structures are high
enough which show the great structural stability of the optimized
structures
Mulliken charge indicator

13. Results & Discussions Geometrical Stability Analysis
Mulliken charge indicator
TiB6
ZrB6
HfB6
TiB8 ZrB8
HfB8
After the adsorption of transition metals
having no imaginary frequency values,
thus the structures gain better stability
than pristine structures.
TiB6, ZrB6 & HfB6 have IR frequency less than 200 Hz which lead to the less
stability of that bonds . But others have IR frequency greater than 200 Hz.

14. Results & Discussions Geometrical Stability Analysis
Mulliken charge indicator
TiB6
ZrB6
HfB6
TiB8 ZrB8
HfB8
After the adsorption of transition metals
having no imaginary frequency values,
thus the structures gain better stability
than pristine structures.
TiB6, ZrB6 & HfB6 have IR frequency less than 200 Hz which lead to the less
stability of that bonds . But others have IR frequency greater than 200 Hz.

15. Results & Discussions Dipole Moment & Band Gap Analysis
Parameters Unit B6 B8 TiB6 ZrB6 HfB6 TiB8 ZrB8 HfB8
E(g)
eV 0.77 2.03 2.03 2.01 1.96 1.45 1.40 1.61
µd
Debye 0.00 0.00 5.35 7.57 7.22 3.71 5.26 5.20
 The tabulated dipole moments for pure B6 and B8 clusters are zero , so there is
no polarity in B6 and B8 clusters, but after adsorbing of transition metals, in
pyramidal structures the dipole moments are large. The most polar structure in the
calculation is ZrB6 and its dipole moment value is 7.56 Debye .
 The band gap for the pure B6 in the DOS spectra is 0.77 eV and for the pristine
B8 is 2.08 eV. After transition metal doping to pure B6 and B8, the largest band
gap value for TiB6 is 2.03 eV and the smallest band gap value for ZrB6 is 1.40
eV.

16. Results & Discussions Dipole Moment & Band Gap Analysis
Parameters Unit B6 B8 TiB6 ZrB6 HfB6 TiB8 ZrB8 HfB8
E(g)
eV 0.77 2.03 2.03 2.01 1.96 1.45 1.40 1.61
µd
Debye 0.00 0.00 5.35 7.57 7.22 3.71 5.26 5.20
 The tabulated dipole moments for pure B6 and B8 clusters are zero , so there is
no polarity in B6 and B8 clusters, but after adsorbing of transition metals, in
pyramidal structures the dipole moments are large. The most polar structure in the
calculation is ZrB6 and its dipole moment value is 7.56 Debye .
 The band gap for the pure B6 in the DOS spectra is 0.77 eV and for the pristine
B8 is 2.08 eV. After transition metal doping to pure B6 and B8, the largest band
gap value for TiB6 is 2.03 eV and the smallest band gap value for ZrB6 is 1.40
eV.

17. Results & Discussions Orbital Analysis
B6_HOMO B6_LUMO B6_DOS
B8_HOMO B8_LUMO B8_DOS
HOMO describes the highest occupied molecular orbital and the LUMO means the lowest
unoccupied molecular orbital of any molecular systems.
It is revealed from the represented HOMO-LUMO maps there is hybridization occur
between the HOMO and LUMO. The DOS spectra for B6 & B8 claimed about the
HOMO-LUMO pictures and the Eg. The band gap for the pure B6 in the DOS spectra is
0.77 eV and for the pristine B8 is 2.08 eV.

18. Results & Discussions Orbital Analysis
TiB6_HOMO TiB6_LUMO TiB6_DOS
ZrB6_HOMO ZrB6_LUMO ZrB6_DOS
After the adsorption of the transition metals the HOMO-LUMO shift greatly in the complex structures,
which increase the Eg, as the band gap increased the reactivity of the structures are decreased, i.e. the
stability of the structures are increased.
The DOS spectra represents after transition metal doping to pure B6 and B8, the largest band gap value
for TiB6 is 2.03 eV and the smallest band gap value for ZrB6 is 1.40 eV.

19. Results & Discussions UV-Vis Analysis
UV-Vis spectra is an optical
analysis for any systems.
It describes the range of light that
can absorb.
 From the UV-Vis spectra it is
revealed that both the pure
structures absorb light in visible
range but after doping the range has
raised up to ultraviolet range which
has medical application.

20. Results & Discussions Circular Dichroism Analysis
TiB6_CD ZrB6_CD HfB6_CD
TiB8_CD ZrB8_CD HfB8_CD
Circular dichorism spectra (CD) is also calculated that shows the complex
structure have chirality but the pure structure not.

21. Results & Discussions Physical Parameters and Chemical
Potential Analysis
Systems
B6 B8 TiB6 ZrB6 HfB6 TiB8 ZrB8 HfB8
EHOMO (eV) -5.60 -5.85 -5.84 -5.47 -5.56 -6.43 -6.17 -6.23
ELUMO (eV) -4.83 -3.82 -3.82 -3.40 -3.59 -4.98 -4.77 -4.62
Chemical
Potential,μ
(eV)
-5.22 -4.84 -4.83 -4.41 -4.57 -5.71 -5.47 -5.43
Eg (eV)
0.77 2.03 2.03 2.02 1.97 1.45 1.41 1.61
Hardness,ŋ
(eV)
0.39 1.02 1.02 1.01 0.98 0.73 0.70 0.81
Softness ,S
(eV-1 )
1.29 0.49 0.49 0.50 0.51 0.69 0.71 0.62
Electrophilicity
, ω (eV)
35.26 11.51 11.50 9.65 10.65 22.41 21.31 18.25
 chemical potential
μ = − (EHOMO + ELUMO)/2
 Hardness
ŋ = (ELUMO − EHOMO)/2
 Softness S = 1/2 ŋ
 Electrophilicity
ω = μ2/2 η

22. Conclusions
 Calculated adsorption energy for doped structures are high enough which
show the great structural stability of the optimized structures.
 After doping by transition metal the electrical band gaps have changed
significantly.
 From the UV-Vis spectra it is revealed that both the pure structures
absorb light in visible range but after doping the range has raised up to
ultraviolet range which has medical application.
 Calculated circular dichorism spectra (CD) that shows the complex
structure have chirality but the pure structure not.

23. Future Aspects
 Energy storage device, gas sensing, magnetic applications can be
investigated.
 Photovoltaic application, superconductivity observation, high electrical
property analysis can also be investigated for B6 & B8 nanoclusters.
 Here only for B6 and B8 nanoclusters, different properties are examined,
but it can be observed for all other boron nanoclusters including B2, B3,
B4, B5, B7 up to B40, may be the same or other properties.
 The future challenge is to produce electronic devices based on hybrid
nanostructures containing B36 Borophene.

24. Acknowledgments
 Dr. Sajal Chandra Mazumdar, Associate Professor & Honorable
Chairman, Department of Physics, Comilla University
 Milon, Lecturer ,Department of Physics, Comilla University
 Professor Dr. Md. Abu Taher, Department of Physics, Comilla University
 Dr. Mohammad Julhash Miah, Associate Professor; Department of Physics, Comilla
University
 Md. Ashiqur Rahman,Assistant Professor, Department of Physics, Comilla University
 Sangita Das, Lecturer,Department of Physics, Comilla University
 Kamrunnahar Kali , Lecturer, Department of Physics, Comilla University
 Ashish Chandra Das, Lecturer,Department of Physics, Comilla University
 All the teachers of Department of Physics, Comilla University
 Department Of Physics , Comilla University

25. Thank you everyone
&
Best wishes for MUJIB BORSHO