Papers by Dr. Sigamani Saravanan
Graphitic Carbon Nitride-Based Dye-Sensitized Solar Cells and Perovskite Solar Cells for Energy Harvesting
EAI/Springer Innovations in Communication and Computing, Dec 31, 2022
Performance of TiO2, Cu-TiO2, and N-TiO2 nanoparticles sensitization with natural dyes for dye sensitized solar cells
Materials Today: Proceedings, 2022
In this work, the eucalyptus and teak leave extracts are used as natural dyes for dye-sensitized ... more In this work, the eucalyptus and teak leave extracts are used as natural dyes for dye-sensitized solar cells (DSSCs). The TiO 2 , copper doped-TiO 2 (Cu-TiO 2), and nitrogen doped-TiO 2 (N-TiO 2) nanoparticles were synthesized by using the sol-gel method. The structural, morphological and elemental properties of the prepared samples were tested by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). XRD revealed the anatase-TiO 2 phase and calculated crystallite sizes are 10, 11.23, and 13.97 nm, correspondingly. SEM micrograph shows the spherical shaped nanoparticles with less agglomeration and primary elements (Ti, O, Cu, N) confirmed by EDS spectra. Further, the nanoparticles used as a photoanode in DSSC device with natural dyes and studied their performance.
Effects of calcination temperatures on structural, functional, morphological, and magnetic properties of strontium ferrite (SrFe2O4) nanoparticles
Kuwait Journal of Science
In this proposed work, the strontium ferrite (SrFe 2 O 4) nanoparticles were successfully synthes... more In this proposed work, the strontium ferrite (SrFe 2 O 4) nanoparticles were successfully synthesized in the presence of strontium nitrate (Sr (NO 3) 2) and ferric nitrate (Fe (NO 3).9H 2 O) as primary sources by using chemical coprecipitation method. The prepared powders were kept different calcinations temperature (650, 750 and 850 C) and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) techniques. The XRD patterns demonstrated the cubic and orthorhombic phase of spinel formation and FTIR transmittance spectra confirmed the presence of strontium ferrite related molecular functional groups. Further, SEM micrograph showed spherical nanoparticles with less agglomerated structure. VSM studies revealed the hard magnetic properties with the highest saturation magnetization (Ms), remanent magnetization (M r) and coercivity (H c) of 22.17 emu/g, 11.807 emu/g and 5662.6 Oe respectively by VSM.
Progress In Electromagnetics Research M
Compared to crystalline silicon solar cells, thin-film solar cells are inexpensive, but a weak ab... more Compared to crystalline silicon solar cells, thin-film solar cells are inexpensive, but a weak absorption of sunlight at a longer wavelength is a significant issue. In this perspective, an efficient light trapping mechanism is needed to facilitate the light-guiding in enhancing light absorption. This paper presents a theoretical investigation of ultrathin amorphous silicon (a-Si) solar cells using the rigorous coupled-wave analysis (RCWA) method. We noticed broadband light absorption of the designed solar cell due to an efficient light trapping geometry. Our proposed design is composed of anti-reflection coating (ITO), an absorbing layer (a-Si), a back reflector (Ag-substrate), top-indium tin oxide (ITO), and bottom-silver (Ag) nanogratings. Using an Ag-back reflector with diffraction gratings demonstrated the improved diffraction and scattering of light, which enhanced light absorption within a 50 nm thick absorbing layer. Compared to the reference solar cell, the proposed ultrathin solar cell endorsed the enhanced photovoltaic conversion, i.e., 19% and 23%, corresponding to the transverse electric (TE) and magnetic (TM) polarization conditions. Furthermore, we explore the investigations of light absorption, current density, field distributions, reflection, transmission, and parasitic losses for the optimal design of ultrathin film (a-Si) solar cells.
Performance of TiO2, Cu-TiO2, and N-TiO2 nanoparticles sensitization with natural dyes for dye sensitized solar cells
Materials Today: Proceedings, 2022
In this work, the eucalyptus and teak leave extracts are used as natural dyes for dye-sensitized ... more In this work, the eucalyptus and teak leave extracts are used as natural dyes for dye-sensitized solar cells (DSSCs). The TiO 2 , copper doped-TiO 2 (Cu-TiO 2), and nitrogen doped-TiO 2 (N-TiO 2) nanoparticles were synthesized by using the sol-gel method. The structural, morphological and elemental properties of the prepared samples were tested by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). XRD revealed the anatase-TiO 2 phase and calculated crystallite sizes are 10, 11.23, and 13.97 nm, correspondingly. SEM micrograph shows the spherical shaped nanoparticles with less agglomeration and primary elements (Ti, O, Cu, N) confirmed by EDS spectra. Further, the nanoparticles used as a photoanode in DSSC device with natural dyes and studied their performance.
Chinese Optics Letters, 2013
Dual-grating structure thin-film silicon solar cells with different front and back grating period... more Dual-grating structure thin-film silicon solar cells with different front and back grating periodicities are designed The geometrical parameters of both gratings are investigated. The reflection is greatly reduced by the front grating, whereas the absorption in the long wavelength is increased because of the back grating. The short circuit current of the combined structure is enhanced by 16.8% for a 1-µm thick c-Si layer compared with that of the conformal grating structure. The short circuit current can be further increased by creating a relative lateral displacement between the front and back gratings. The displacement results in a more remarkably enhanced absorption when the thickness of the active layer is reduced, indicating its importance in the design of ultra-thin high-efficiency solar cells.
RASAYAN Journal of Chemistry
In this work, we have adopted a sol-gel spin-coating technique and prepared alternative TiO2/Si3N... more In this work, we have adopted a sol-gel spin-coating technique and prepared alternative TiO2/Si3N4 multilayers on glass substrates. These alternating layers of TiO2/Si3N4 thin film samples were calcinated at two different temperatures and studied for their optical performance. The optical properties of fabricated thin films were investigated by UV-Visible spectrophotometer, X-ray diffractometer (XRD), Fourier transform infrared (FTIR), and Raman spectroscopy. UV-visible spectra showed broader and higher optical reflectance in the visible spectral region. FTIR transmission spectra show Ti-O-Ti and Si-N stretching modes at around 600 and 881 cm-1. XRD pattern confirmed the presence of anatase-TiO2 and α-Si3N4 phases. Finally, Raman spectra revealed the presence of anatase-TiO2 and N-Si vibration modes.
Optimization of distributed Bragg’s reflectors in thin film solar cells
Materials Today: Proceedings
Optical investigation of sol–gel-synthesized and spin-coated SiO2/TiO2 multilayers
Nanomaterials and Energy
In this work, silicon dioxide (SiO2)/titanium dioxide (TiO2) multilayer films were deposited on s... more In this work, silicon dioxide (SiO2)/titanium dioxide (TiO2) multilayer films were deposited on silicon substrates through the sol–gel spin-coating technique using the precursors titanium butoxide and tetraethyl orthosilicate. After the preparation, the various optical and morphological properties of the films were studied by using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and ultraviolet–visible (UV–Vis) spectroscopy. The XRD patterns showed intense diffraction peaks, which were found to correspond to anatase titanium dioxide and it matched well the standard Joint Committee on Powder Diffraction Standards file. The crystallite sizes of the prepared samples were calculated as 24 nm for three stacks of silicon dioxide/titanium dioxide thin films and 30 nm for five stacks of silicon dioxide/titanium dioxide thin films using Debye–Scherrer’s formula. The FTIR transmittance spectra confirmed Si–O–Ti vibrational modes at 800 and 960 cm−1 with related functio...
Photonic band gap analysis of 1D TiO2/SiO2 photonic crystals using plane wave method for thin film solar cell applications
IOP Conference Series: Materials Science and Engineering
The properties of photonic crystals that allow or inhibit the propagation of electromagnetic (EM)... more The properties of photonic crystals that allow or inhibit the propagation of electromagnetic (EM) waves in between photonic band gap (PBG) regimes have proved to be significant. In this work, we investigated the PBG analysis of one-dimensional TiO2/SiO2 photonic crystal using plane wave method (PWM). The PBG width depends of on the various optical parameters such as lattice constant (Λ), center wavelength (λc), thickness of the layers (d), dielectric constant (ε) and refractive indices (n). Among various parameters, the center wavelength (300-1100nm), the thickness of TiO2 (28-103 nm) and SiO2 (51-189 nm) layers were optimized for the tuned bandgap. The obtained results revealed that the PBG shifting towards the lower frequency region and reducing the size due to the increment of center wavelength and thicknesses. This result is useful for the understanding the way of photon propagation within artificial structure and it could be possible for the better back reflector in thin film s...
The role of photonic and plasmonic modes in ultrathin amorphous silicon solar cells using finite difference time domain method
Materials Today: Proceedings
In photovoltaic market, the enhancement of optical performance in an ultra-thin film amorphous si... more In photovoltaic market, the enhancement of optical performance in an ultra-thin film amorphous silicon (a-Si) solar cell is significant. Our main objective is to design and simulate a highest current density by using various nanostructures integrated with ultrathin a-Si solar cells. In this proposed work, the various photonic and plasmonic nanostructures were used in front side of the absorber layer and enhanced the collection of charge carriers due to that an improved the current density in ultrathin a-Si solar cells. Using finite-difference time-domain (FDTD) method, the obtained results indicate the optimized SiO 2 nanogratings and Si 3 N 4 thin films acting as an anti-reflection coating (ARC) layer with air medium (AM1.5) which showed significant current density of 16.25 mA/cm 2 in ultra-thin a-Si solar cells. Finally, the light trapping mechanism evidenced the importance of nanostructures using transverse electric (TE) and magnetic (TM) field distributions by changing the various incident wavelength.
Study of ultrathin‐film amorphous silicon solar cell performance using photonic and plasmonic nanostructure
International Journal of Energy Research, 2021
The photonic and plasmonic nanostructures are highly feasible for enhanced light trapping mechani... more The photonic and plasmonic nanostructures are highly feasible for enhanced light trapping mechanisms. These nanostructures hold great promises for better photovoltaic performance by yielding the highest light‐harvesting photons within the few nanometer absorber regions. The shed light on the nano‐scaled structures (thin films and nanogratings) is responsible for the highest scattering mechanism with the omnidirectional diffraction angles and enhanced life time of the photons. In this research work, we have focused on improved ultrathin film amorphous silicon (a‐Si) solar cell performance, which was integrated by top‐SiO2 and bottom‐Ag nanogratings as a backside reflector by using rigorous coupled‐wave analysis method. The SiO2 antireflection coating, nanogratings, and absorber (a‐Si) layer thicknesses were optimized for better photovoltaic performance. With the influence of optimization parameters, the highest current density of 27.03 and 33.53 mA/cm2 were obtained from transverse electric and transverse magnetic polarization conditions due to the surface guided‐mode, Fabry–Perot resonance, surface excitation, localized fields, and surface plasmon polariton modes.
AIP Advances, 2015
Thin film solar cells are cheaper but having low absorption in longer wavelength and hence, an ef... more Thin film solar cells are cheaper but having low absorption in longer wavelength and hence, an effective light trapping mechanism is essential. In this work, we proposed an ultrathin crystalline silicon solar cell which showed extraordinary performance due to enhanced light absorption in visible and infrared part of solar spectrum. Various designing parameters such as number of distributed Bragg reflector (DBR) pairs, anti-reflection layer thickness, grating thickness, active layer thickness, grating duty cycle and period were optimized for the optimal performance of solar cell. An ultrathin silicon solar cell with 40 nm active layer could produce an enhancement in cell efficiency ∼15 % and current density ∼23 mA/cm2. This design approach would be useful for the realization of new generation of solar cells with reduced active layer thickness.
Design and Analysis of Thin Film Based Silicon Solar Cells for Efficient Light Trapping
Springer Proceedings in Physics, 2015
ABSTRACT Silicon based solar cells are still preferable due to its existing technology with inexp... more ABSTRACT Silicon based solar cells are still preferable due to its existing technology with inexpensive fabrication cost. However, silicon solar cells are having drawback of weak absorption in longer wavelength due its indirect band gap and needs efficient light trapping in active region. In this paper, we present a design of solar cells based on top anti-reflection coating (ARC) layer and back reflector which is composed of distributed Bragg reflector (DBR) and diffraction grating (GRA) using finite difference time domain (FDTD) method. Simulations show efficient trapping of photon in active region as comparison to reference solar cell. A relative enhancement of cell efficiency *54 and 60 % is observed for designed solar cells C2 and C3 respectively. This enhancement in performance of solar cells is attributed to the increased absorption and quantum efficiency in red and infrared part of incident solar spectrum.
Procedia Materials Science, 2015
Silicon based solar cells are having weak absorption of light and hence, needs light trapping mec... more Silicon based solar cells are having weak absorption of light and hence, needs light trapping mechanism for the enhancement of solar cell performance. This paper explores the designing of thin film solar cells based on distributed Bragg reflector (DBR) and diffraction grating using FDTD method. Three DBR pairs with 0.8 μm center wavelength were found to be good choice for better performance of solar cells. A relative enhancement in short-circuit current is observed for 5, 10 and 20 μm cell thicknesses respectively which corresponds to an enhanced absorption in the wavelength 450-1100 nm. Use of three binary layer based grating yields enhanced quantum efficiency as comparison to single layer grating based solar cell.
Materials Today: Proceedings, 2015
In this paper, c-Si thin film solar cell design with different grating structures are studied by ... more In this paper, c-Si thin film solar cell design with different grating structures are studied by using finite difference time domain (FDTD) method. This designing approach is incorporated with an anti-reflection coating (ARC), Si-active region alongwith a top and bottom gratings. The performance and the ability of top (dielectric) and bottom (metal) gratings on the optical wave propagation within crystalline silicon thin film solar cells were investigated. The optimized nano-gratings play a key role to enhance the light absorption in thin film silicon solar cells. The design combination of single, binary and triangular grating structures is proposed to improve the light absorption in active region. We have compared the performance of designed solar cells and found optimal enhancement in light absorption for the case of triangular grating based solar cell design.
Nanoscale Research Letters, 2014
Light-trapping structures are more demanding for optimal light absorption in thin film silicon so... more Light-trapping structures are more demanding for optimal light absorption in thin film silicon solar cells. Accordingly, new design engineering of solar cells has been emphasized and found to be effective to achieve improved performance. This paper deals with a design of thin film silicon solar cells and explores the influence of bottom grating and combination of top and bottom (dual) grating as a part of back reflector with a distributed Bragg reflector (DBR). Use of metal layer as a part of back reflector has found to be promising for minimum requirement of DBR pairs. The effect of grating and anti-reflection coating thicknesses are also investigated for absorption enhancement. With optimization, high performance has been achieved from dual grating-based solar cell with a relative enhancement in short-circuit current approximately 68% while it was approximately 55% in case of bottom grating-based solar cell. Our designing efforts show enhanced absorption of light in UV and infrared part of solar spectrum.
AIP Advances, 2014
The influence of various designing parameters were investigated and explored for high performance... more The influence of various designing parameters were investigated and explored for high performance solar cells. Single layer grating based solar cell of 50 μm thickness gives maximum efficiency up to 24 % whereas same efficiency is achieved with the use of three bilayers grating based solar cell of 30 μm thickness. Remarkably, bilayer grating based solar cell design not only gives broadband absorption but also enhancement in efficiency with reduced cell thickness requirement. This absorption enhancement is attributed to the high reflection and diffraction from DBR and grating respectively. The obtained short-circuit current were 29.6, 32.9, 34.6 and 36.05 mA/cm2 of 5, 10, 20 and 30 μm cell thicknesses respectively. These presented designing efforts would be helpful to design and realize new generation of solar cells.
International Journal of Renewable Energy Development
The issues related to global energy needs and environmental safeties as well as health crisis are... more The issues related to global energy needs and environmental safeties as well as health crisis are some of the major challenges faced by the human, which make us to generate new pollution-free and sustainable energy sources. For that the optical functional nanostructures can be manipulated the confined light at the nanoscale level. These characteristics are emerging and leading candidate for the solar energy conversion. The combination of photonic (dielectric) and plasmonic (metallic) nanostructures are responsible for the development of better optical performance in solar cells. Here, the enhancement of light trapping within the thin active region is the primary goal. In this work, we have studied the influence of front-ITO (rectangular) and back-Ag (triangular) nanogratings were incorporated with ultrathin film amorphous silicon (a-Si) solar cell by using rigorous coupled wave analysis (RCWA) method. The improvement of light absorption, scattering (large angle), diffraction and fie...
Engineered Science, 2025
In this paper, we investigated the light trapping mechanism of thin-film amorphous silicon (a-Si)... more In this paper, we investigated the light trapping mechanism of thin-film amorphous silicon (a-Si) solar cells using rigorous coupled wave analysis (RCWA) method. Using optical modeling, the distributed Bragg's reflector (DBR) is optimized and consists of alternative layers of Si and SiO2 materials. The optical reflectivity of distinct DBR layers was investigated by changing various center wavelengths (400, 600, 800 and 1000 nm). These reflectance spectra showed higher or wider photonic band gap shifts due to the thickness of each layer and incident wavelength. Further, the studied new conformal thin-film solar cell architecture includes nanostructures (indium tin oxide anti-reflection coating and silver nanogratings) and optimized DBR used as backreflector. The DBRs and nanogratings helped to fold back the shorter and longer wavelength of light towards the active (a-Si) region and enhanced photon path length and life time of photon. Under normal radiation, the collection of the photons was enhanced, and also the charge carriers (electron-hole) pair generations were remarkably improved in active regions with low recombination losses. These nanostructures yielded a better light harvesting mechanism and the highest current density of 25.16 mA/cm 2 .
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Papers by Dr. Sigamani Saravanan