4.1 STRUCTURAL STUDIES
Figure 1 shows the X – ray diffraction pattern of nanocrystalline Bi2Se3 for as-prepared sample and samples annealed at 650 °C for 12 h in argon gas atmosphere. The X- ray diffraction studies were carried out for 2θ angle ranges from 20° to 80°. The target Cu Kα1 radiation (λ=1.5406 Å) was used for this measurement. The XRD pattern of as-prepared nanocrystalline Bi2Se3 sample diffraction peaks and 650 ºC annealed for 12 h in argon gas atmosphere sample. The diffraction peaks for Bi2Se3 nanoparticles are 2θ = 24.82°, 27.79°, 30.48°, 32.99°, 35.32°, 37.55°, 39.67°, 41.69°, 43.61°, 45.51°, 49.08°, 52.47°, 54.14°, 55.71°, 60.40°, 61.86°, 64.79°, 67.69°, 73.23° and 78.69° corresponding to identified to originate the diffraction hkl planes
(101), (104), (221), (107), (018), (332), (444), (1010), (110), (443), (555), (024), (200), (220), (655), (543), (442), (0213), (464) and (1211) respectively. The XRD analysis shows that the Bi2Se3 nanomaterials exhibit the rhombohedral structure of Bi2Se3 [space group: R3m with lattice constants a = 4.1396 Å and c = 28.636 Å (JCPDS = 33–0214 and 89-2008). From the X-ray diffraction measurement, a very high intensity peak obtained at 2θ = 27.84° (104) which correspond to Bi2Se3 nanoparticles.
The grain size of the prepared samples was calculated using Debye’s Scherrer formula
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Where D is a size of the nanoparticles, θ = diffraction angle, λ = wavelength of X-rays and β = line broadening at Full Width Half Maximum (FWHM). The average grain size was calculated above formula from diffraction pattern was found to be 25 nm for as-prepared sample and 37 nm for 650°C for 12 hours annealed sample.
4.2 HIGH RESOLUTION SCANNING ELECTRON MICROSCOPY WITH EDS STUDIES
Figure 2 (a-c) shows the high resolution SEM morphology of as-prepared Bi2Se3 nanocrystalline sample with EDS spectrum analysis. The images indicate that mostly well crystalline nature of as-prepared Bismuth Selenide (Bi2Se3) sample, which is confirmed through XRD analysis.
We found that most of the Bi2Se3 nanocrystalline have nano-rod and nano-flakes mixture with porous surface morphology nature as shown in Fig. 2.1 (a-b). Figure 2.1(c) shows the Energy dispersive spectroscopy (EDS) of Bi2Se3 as-prepared sample and confirms the presence of Bi and Se. Figures 2.2 (a-c) show the HRSEM images of Bi2Se3 nanocrystalline sample annealed at 650°C for 12 h in argon gas atmosphere with EDS spectrum analysis.
The images indicate that mostly Selenide (Se) nanoparticles well incorporated into the Bismuth materials as shown in Fig. 2.2 (a). The white crystalline of Se-nanoparticles is dispersed on the Bi materials at high magnification 500 nm. The evidences of that formation Bi2Se3 nanoparticle as shown in Fig. 2.2(b). Figure 2.2(c) shows the EDS spectrum of Bi2Se3 sample measurements confirms that Bi and Se elements are presented.
4.3 RAMAN STUDIES
Figure 3 shows Raman spectra of as prepared and annealed at 650 °C for 12 h in argon gas atmosphere sample. Raman spectroscopy has been an important investigation way as a high-resolution probe technology of crystal structure and vibrational properties of materials. The rhombohedral crystal structure of Bi2Se3 corresponding to the [space group D53d (R3m)] symmetry and there are five atoms in a primitive unit cell and each unit cell consisting of three few-quintuple layers stacked together by weak van der Waals forces. The atomic arrangement of Bi2Se3 is distinctive (i.e., every repeating unit in the crystal is a quintuple layer of Se-Bi-Se-Bi-Se), which are held collectively through susceptible van der Waals forces. The Raman spectrum of Bi2Se3 with 785 nm excitation laser was also performed to investigate the four Raman active modes (Eg1, A1g1, Eg2 and A1g2) of this sample. The letters “E” and “A” indicate the in-plane and out-of-plane (C- axis) lattice vibrations, and subscript “g” denote Raman active. Group theory predicts 12 zone center optical phonon modes in this crystal symmetry, out of 12 optical phonon modes only 4 modes are Raman active, they are E1g, A11g, E2g and A21g verified polarization dependence, out-of-plane A11g and A21g, in-plane E1g and E2g modes. There are three optical phonon modes are clearly seen in the spectrum. They are ~124 cm-1, 262 cm-1 and 524 cm-1. The peak at 124 cm-1 corresponding to the well known E2g mode indicate that good quality of the crystal structure.
The peak at 262 cm-1 due to combination of A11g and A21g modes indicate that well crystallinity of this sample. Raman spectrum appears in the higher frequency range, this is due to stronger bonding forces, i.e the peak at 524 cm-1 or may arise due to the overtones of A11g and E2g modes. The observed frequencies are well compared with the previously reported experimental and calculated phonon vibration modes of Bi2Se3. If the polarization of x-direction is present (z (xx)̅z geometry), one will observe phonons denoted by A11g, A12g and E2g. If one measures scattered light with a polarization in the y direction, only E2g will appear in the Raman spectrum. This can be understood by considering the nature of the atomic displacements associated with the phonon modes.
4.4 CYCLIC VOLTAMMETRY STUDIES
The redox nature of Bi2Se3 nanoparticles was carried out by cyclic voltammetry. This process was done in a three electrode system, Glass Carbon Electrode (GCE) as a working electrode, Ag/AgCl electrode as a reference electrode and platinum wire as a counter electrode. The modified Bi2Se3 nanoparticles/GCE was carried out in TBPA (Tetra butyl ammonium perchlorate) used as a supporting electrolyte in acetonitrile (CH3CN) condition at scan rate 50mV/s. The modified Bi2Se3 nanoparticles/GCE obtained well define redox peak (Ipa = 0.0114 and Ipc = − 0.155) as shown in Fig. 4. This redox behavior was due to Bi3+ converted into Bi2+ and Bi metallic state. This redox peak was confined the formation of Bi2Se3 nanoparticles. Bi2Se3 nanoparticles annealed at 650°C for 12 h sample. This is modified on the GCE (Bi2Se3 nanoparticles/GCE) was obtained well known the higher redox peak current with IPa = 0.021(µA) and IPc = − 0.144 (µA) as shown in Fig. 4.
Table The electrochemical response of Bi2Se3 nanoparticles in 0.1M H2SO4 at 50 mVs− 1
Material
|
Oxidation current (µA)
|
Oxidation potential (V)
|
Reduction Current (µA)
|
Reduction potential (V)
|
Bi2Se3- As prepared
|
0.0114
|
1.873×10− 4
|
− 0.155
|
− 2.111×10− 4
|
Bi2Se3-12 hours
|
0.021
|
1.852×10− 4
|
− 0.144
|
− 2.804×10− 4
|
From this data was clearly indicated that increasing the crystallinity of Bi2Se3 NPs. The crystalline further confirms the XRD data. It gives a broad peak, hence it shows that the three electron (3.4) transfer process was evident in this redox behavior. Here the electron calculating from below equation.
![](data:image/png;base64,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)
Where ip is the current, R is the Gas Constant (8.314 J/mol K), T is the Temperature (298 K), F is the Faradays Constant (96,485.33 A/mol), Q is the Charge and ν is the Scan Rate (50 mV/Sec).
4.5 IMPEDANCE SPECTROSCOPY STUDIES OF Bi2Se3 NANOPARTICLES
The complex impedance plots measured at different temperatures ranging from RT to 70 ºC with the frequency range of 1 Hz – 1 X 106 Hz are shown in Fig. 5. It should be noted from this plots most of the depressed semicircle are exists, whose center is slightly shifted below the real axis (this behavior is commonly considered to be an indication of a non-Debye relaxation process). At low temperatures as well as low measuring frequencies the curve slightly deviates from a perfect semicircle.
The impedance plots are fitted with complex non-linear least square fit (CNLLS) to acquire the resistance of the sample. With the geometry of the sample, this resistance value has been converted into conductivity using the relation,
![](data:image/png;base64,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)
Here R is the resistance of the sample, A is the area of the cross-section and l is the thickness of the pellet. The high temperature electrical conductivity studies were performed as-prepared and annealed sample using impedance spectroscopy. It shows that very high resistance as well as grain effect curve behavior.