List of Publications by Vipinraj Sugathan
This is the updated list of publication of my work at various National and International Journals... more This is the updated list of publication of my work at various National and International Journals and conferences
Papers by Vipinraj Sugathan
Sustainability, Jul 6, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Chemical Communications
Perovskite-inspired absorbers are promising for sustainable indoor light-harvesting. Defect mitig... more Perovskite-inspired absorbers are promising for sustainable indoor light-harvesting. Defect mitigation and device operational stability need attention to accelerate the development of air-stable and low-toxicity photovoltaics.
Perovskite-inspired Cu2AgBiI6 (CABI) absorber has recently gained increased popularity due to its... more Perovskite-inspired Cu2AgBiI6 (CABI) absorber has recently gained increased popularity due to its low toxicity, intrinsic air stability, and wide bandgap ≈ 2 eV, which makes it ideal for indoor photovoltaics (IPVs). However, the considerable presence of both intrinsic and surface defects is responsible of the still modest indoor power conversion efficiency (PCE(i)) of CABI- based IPVs, with the short-circuit current density (JSC) being nearly half of the theoretical limit. Herein, we introduce antimony (III) (Sb3+) into the octahedral lattice sites of CABI structure, leading to CABI-Sb with substantially larger crystalline domains than CABI. The alloying of Sb3+ with bismuth (III) (Bi3+) induces changes in the local structural symmetry, in turn causing a remarkably increased formation energy of intrinsic defects. This accounts for the overall reduced defect density in CABI-Sb. CABI-Sb IPVs feature an outstanding PCE(i) of nearly 10% (9.53%) at 1000 lux, which represents an almost do...
The Journal of Physical Chemistry Letters
Silver bismuth iodide has been explored extensively for its potential as absorbers in perovskite ... more Silver bismuth iodide has been explored extensively for its potential as absorbers in perovskite inspired solar cells, due to its less toxic environment friendly nature. However, the conventional spin coating methods employed for synthesis of thin films make them dubious when it comes to commercial applications. These methods can be tedious and can facilitate fabrication of one to a few devices in a single run, making it unfitting for commercial applications, though they may be useful for lab scale device fabrication intended for research purposes. Here we propose a modified evaporation method which can be employed for large scale fabrication of silver bismuth iodide thin films. The method involves sequential evaporation of metallic layers of silver and bismuth followed by exposure to sublimated iodine vapours to obtain highly uniform pin hole free silver bismuth iodide thin films. Following this method, with multiple optimization steps, we were able to synthesise Ag3BiI7 thin films...
ZnO etc and works as a photo electrochemical cell. In this research work, the processes occurring... more ZnO etc and works as a photo electrochemical cell. In this research work, the processes occurring at the 3 interfaces of the DSSC (FTO/TiO 2, TiO 2 /dye/electrolyte and electrolyte/Pt-FTO) have been studied with the help of the two diode model and the relevant equations. For these processes, the effect of temperature and Solar Insolation on the current density-voltage characteristics is studied making use of the MATLAB Graphical User Interface. MATLAB GUI makes use of the interface to create software which inputs the user values for temperature in Kelvin and Solar Insolation in kW/m 2
The Dye-sensitized Solar Cell (DSSC) is a cell that involves photo-electrochemical process of con... more The Dye-sensitized Solar Cell (DSSC) is a cell that involves photo-electrochemical process of conversion of incident photon energy to electrical energy. It functions similar to a plant cell, involved in photosynthesis. The role of conversion of incident photon energy to electron flow is played by the Dyes used in the fabrication process of the DSSC. The light harvesting efficiency of the Dye should be improved, for an ideal cell with maximum efficiency. This paper concentrates on synthesis of novel dyes from natural plant sources, their characterization and study to decide on the most compatible dye for a typical DSSC. Four new dyes were extracted from plant sources-flowers of Thevetia Peruviana, Acalypha Hispida, and Celasia Cristata, and leaves of Acalypha Wilkesiana. The extracted dyes were studied using visible spectro-photometer. The absorbance, transmittance and concentration were observed. The paper consists of the comparative analysis of the characteristics obtained for the ...
During my research work, I came across this interesting segment of Third Generation Solar Cells, ... more During my research work, I came across this interesting segment of Third Generation Solar Cells, i.e. Dye Sensitized Solar Cells (DSSC). I realized the importance of putting together the fundamentals of the DSSC, for convenience of the researchers who choose to contribute to this section. This book is a result of a sincere and selfless effort from me and my co-authors. We have tried our best to bring forth all the basic information and scope of the DSSC. This book would prove to be of great use to researchers, especially the beginners in the field of DSSC.
Physical Review Materials, 2018
Solar energy plays an important role in substituting the ever declining source of fossil fuel ene... more Solar energy plays an important role in substituting the ever declining source of fossil fuel energy. Finding novel materials for solar cell applications is an integral part of photovoltaic research. Hybrid Lead halide perovskites are one of, if not the most, well sought material in the photovoltaic research community. Its unique intrinsic properties, flexible synthesis techniques, and device fabrication architecture made the community highly buoyant over the past few years. Yet, there are two fundamental issues which still remain a concern i.e. stability in external environment and toxicity due to Pb. This led to a search for alternative materials. More recently, double perovskite (A2BB X6 (X=Cl,Br,I)) materials have emerged as a promising choice. Few experimental synthesis and high throughput computational studies have been carried out to check for promising candidates of this class. The main outcome from these studies, however, can essentially be summarized into two categories, (i) either they have indirect band gap or (ii) direct but large optical band gap which are not suitable for solar device. Here we propose a large set of stable double perovskite materials, Cs2BB X6 (X=Cl,Br,I), which show indirect to direct band gap transition via small Pb +2 doping at both B and B sites. This is done by careful band (orbital) engineering using first principles calculations. This kind of doping has helped to change the topology of band structure triggering the indirect to direct transition which are optically allowed. It also reduces the band gap significantly, bringing it well in the visible region. We also simulated the optical absorption spectra of these systems and found comparable/higher absorption coefficient and solar efficiency with respect to the state of the art photovoltaic absorber material CH3NH3PbI3. A number of materials Cs2(B0.75Pb0.25)(B 0.75Pb0.25)X6 (for various combinations of B, B & X) are found to be promising, some with better stability and solar efficiency than CH3NH3PbI3, but with much less toxicity. Experimental characterization of one of the material, Cs2(Ag0.75Pb0.25)(Bi0.75Pb0.25)Br6 is carried out. Measured properties such as band gap and chemical stability agrees fairly well with the theoretical predictions. This material is shown to be even more stable than CH3NH3PbI3, both under the sufficient humidity (∼55%) and temperature (T=338 K), and hence has potential to become better candidate than the state of the art material.
Renewable and Sustainable Energy Reviews, 2015
Dye Sensitized Solar Cell (DSSC) is considered to be one of the most promising technological deve... more Dye Sensitized Solar Cell (DSSC) is considered to be one of the most promising technological developments in the field of Solar Cells. It is basically a cell that imitates the process seen in plant cells to produce energy. It is a photo-electrochemical cell, considering the electron moments caused by the combined effect of the photon energy and the chemical reactions. The DSSC being transparent to some extent and comparatively cheaper than conventional solar photo-voltaic, can be a potential energy source for the future. But there are many aspects that need to be worked upon before declaring it as a feasible commercial product. The paper emphasizes on these aspects and the various improvements that the DSSC has gone through in recent years. This is a detailed review of the work done to improve the performance of DSSC, with supporting data. A comparative study of the effect of various suggested modification to the different components of DSSC has been done. This would give a clear idea about the most recent improvements done in DSSC with respect to the various components. It includes a summary of the suggested improvements by various researchers, bifurcated into different sections with respect to the different components of the DSSC. It was observed that incorporating graphene sheets of various sizes in the photo anode helped to improve the efficiency of DSSC significantly, giving a maximum efficiency of 6.62%. In case of novel dyes used in the DSSC fabrication the D-A-pi-A indoline dyes showed a great enhancement in the cell efficiency, with efficiency of up to 6.9%. Incorporation of Pt in counter electrodes and 3D-CE also showed notably good efficiency in DSSC, the efficiency improving up to 8.8%.
Measuring the Photosynthetically Active radiations (PAR) is useful in various agricultural applic... more Measuring the Photosynthetically Active radiations (PAR) is useful in various agricultural applications. However the available measuring instruments for PAR is generally costly as compared to the lux meter and not easily available at all places. This paper is an attempt to establish a relationship between the PAR measurement and the luminous intensity measurement obtained using lux meter. Similarly a relation between PAR and the irradiance is established. A 3-Dimensional representation of the relation between the photon value, lumens and irradiance is also obtained. It also includes a report and graphical representation and analysis produced using the Sigmaplot software. The future development possible is also included.
2013 International Conference on Green Computing, Communication and Conservation of Energy (ICGCE), 2013
ABSTRACT In the 21 st century solar energy is predicted to serve as a major source of energy, bei... more ABSTRACT In the 21 st century solar energy is predicted to serve as a major source of energy, being the only source having the potential to fulfill the ever increasing energy needs. Most of the large scale solar farms employ flat plate photovoltaic concept, so the installation footprint and shadow effect causes a huge drop in the electrical efficiency of the system. This paper aims at developing a methodology to reduce the area requirements in solar power generation. It proposes the development of a triangular prism shaped solar photovoltaic unit, which would reduce the required area for installation of the panels as opposed to the conventional method. The paper consists of the study of a lab level experimental setup of the proposed model, and comparison of its performance with conventional flat plate solar cells. The use of reflecting mirrors within the setup helps improve the efficiency of the setup, than the panels placed in the same area by conventional method. It also includes scope of future development.
Small
The perovskite‐inspired Cu2AgBiI6 (CABI) material has been gaining increasing momentum as photovo... more The perovskite‐inspired Cu2AgBiI6 (CABI) material has been gaining increasing momentum as photovoltaic (PV) absorber due to its low toxicity, intrinsic air stability, direct bandgap, and a high absorption coefficient in the range of 105 cm−1. However, the power conversion efficiency (PCE) of existing CABI‐based PVs is still seriously constrained by the presence of both intrinsic and surface defects. Herein, antimony (III) (Sb3+) is introduced into the octahedral lattice sites of the CABI structure, leading to CABI‐Sb with larger crystalline domains than CABI. The alloying of Sb3+ with bismuth (III) (Bi3+) induces changes in the local structural symmetry that dramatically increase the formation energy of intrinsic defects. Light‐intensity dependence and electron impedance spectroscopic studies show reduced trap‐assisted recombination in the CABI‐Sb PV devices. CABI‐Sb solar cells feature a nearly 40% PCE enhancement (from 1.31% to 1.82%) with respect to the CABI devices mainly due to...
DyeSensitizedSolarCell(DSSC)isconsideredtobeoneofthemostpromisingtechnological
developments inthe... more DyeSensitizedSolarCell(DSSC)isconsideredtobeoneofthemostpromisingtechnological
developments inthe field ofSolarCells.Itisbasicallyacellthatimitatestheprocessseeninplant
cells toproduceenergy.Itisaphoto-electrochemicalcell,consideringtheelectronmomentscausedby
the combinedeffectofthephotonenergyandthechemicalreactions.TheDSSCbeingtransparentto
some extentandcomparativelycheaperthanconventionalsolarphoto-voltaic,canbeapotentialenergy
source forthefuture.Buttherearemanyaspectsthatneedtobeworkeduponbeforedeclaringitasa
feasible commercialproduct.Thepaperemphasizesontheseaspectsandthevariousimprovementsthat
the DSSChasgonethroughinrecentyears.Thisisadetailedreviewoftheworkdonetoimprovethe
performance ofDSSC,withsupportingdata.Acomparativestudyoftheeffectofvarioussuggested
modification tothedifferentcomponentsofDSSChasbeendone.Thiswouldgiveaclearideaaboutthe
most recentimprovementsdoneinDSSCwithrespecttothevariouscomponents.Itincludesasummary
of thesuggestedimprovementsbyvariousresearchers,bifurcatedintodifferentsectionswithrespectto
the differentcomponentsoftheDSSC.Itwasobservedthatincorporatinggraphenesheetsofvarious
sizes inthephotoanodehelpedtoimprovetheefficiency ofDSSCsignificantly,givingamaximum
efficiency of6.62%.IncaseofnoveldyesusedintheDSSCfabricationtheD-A-pi-Aindolinedyesshowed
a greatenhancementinthecellefficiency,withefficiency ofupto6.9%.IncorporationofPtincounter
electrodes and3D-CEalsoshowednotablygoodefficiency inDSSC,theefficiency improvingupto8.8%.
In the 21st century solar energy is predicted
to serve as a major source of energy, being the onl... more In the 21st century solar energy is predicted
to serve as a major source of energy, being the only
source having the potential to fulfill the ever increasing
energy needs. Most of the large scale solar farms
employ flat plate photovoltaic concept, so the
installation footprint and shadow effect causes a huge
drop in the electrical efficiency of the system. This
paper aims at developing a methodology to reduce the
area requirements in solar power generation. It
proposes the development of a triangular prism shaped
solar photovoltaic unit, which would reduce the
required area for installation of the panels as opposed
to the conventional method. The paper consists of the
study of a lab level experimental setup of the proposed
model, and comparison of its performance with
conventional flat plate solar cells. The use of reflecting
mirrors within the setup helps improve the efficiency of
the setup, than the panels placed in the same area by
conventional method. It also includes scope of future
development.
The Dye-sensitized Solar Cell (DSSC) is a variant of thin film solar cells that can be defined as... more The Dye-sensitized Solar Cell (DSSC) is a variant of thin film solar cells that can be defined as a photo-electrochemical cell. It functions similar to a plant cell, involved in photosynthesis. The power conversion efficiency of the DSSC largely depends on the capabilities of the dye used in the fabrication. The light harvesting efficiency of the Dye should be maximum, in order to obtain a good efficiency from the cell. In this paper, the synthesis of new organic dyes has been proposed. Natural sources of dyes like Bougainvillea Spectabilis, Thevetia Peruviana, and Acalypha Hispida have been selected. The dyes have been extracted and their characteristics have been studied. The absorbance, transmittance and concentration were observed using the visible spectro-photo meter. The paper consists of the comparative analysis of the characteristics obtained for the different dyes and also the effect on the absorbance properties on mixing of two or more dyes. The graphical representation of the data is included for better understanding.
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List of Publications by Vipinraj Sugathan
Papers by Vipinraj Sugathan
developments inthe field ofSolarCells.Itisbasicallyacellthatimitatestheprocessseeninplant
cells toproduceenergy.Itisaphoto-electrochemicalcell,consideringtheelectronmomentscausedby
the combinedeffectofthephotonenergyandthechemicalreactions.TheDSSCbeingtransparentto
some extentandcomparativelycheaperthanconventionalsolarphoto-voltaic,canbeapotentialenergy
source forthefuture.Buttherearemanyaspectsthatneedtobeworkeduponbeforedeclaringitasa
feasible commercialproduct.Thepaperemphasizesontheseaspectsandthevariousimprovementsthat
the DSSChasgonethroughinrecentyears.Thisisadetailedreviewoftheworkdonetoimprovethe
performance ofDSSC,withsupportingdata.Acomparativestudyoftheeffectofvarioussuggested
modification tothedifferentcomponentsofDSSChasbeendone.Thiswouldgiveaclearideaaboutthe
most recentimprovementsdoneinDSSCwithrespecttothevariouscomponents.Itincludesasummary
of thesuggestedimprovementsbyvariousresearchers,bifurcatedintodifferentsectionswithrespectto
the differentcomponentsoftheDSSC.Itwasobservedthatincorporatinggraphenesheetsofvarious
sizes inthephotoanodehelpedtoimprovetheefficiency ofDSSCsignificantly,givingamaximum
efficiency of6.62%.IncaseofnoveldyesusedintheDSSCfabricationtheD-A-pi-Aindolinedyesshowed
a greatenhancementinthecellefficiency,withefficiency ofupto6.9%.IncorporationofPtincounter
electrodes and3D-CEalsoshowednotablygoodefficiency inDSSC,theefficiency improvingupto8.8%.
to serve as a major source of energy, being the only
source having the potential to fulfill the ever increasing
energy needs. Most of the large scale solar farms
employ flat plate photovoltaic concept, so the
installation footprint and shadow effect causes a huge
drop in the electrical efficiency of the system. This
paper aims at developing a methodology to reduce the
area requirements in solar power generation. It
proposes the development of a triangular prism shaped
solar photovoltaic unit, which would reduce the
required area for installation of the panels as opposed
to the conventional method. The paper consists of the
study of a lab level experimental setup of the proposed
model, and comparison of its performance with
conventional flat plate solar cells. The use of reflecting
mirrors within the setup helps improve the efficiency of
the setup, than the panels placed in the same area by
conventional method. It also includes scope of future
development.
developments inthe field ofSolarCells.Itisbasicallyacellthatimitatestheprocessseeninplant
cells toproduceenergy.Itisaphoto-electrochemicalcell,consideringtheelectronmomentscausedby
the combinedeffectofthephotonenergyandthechemicalreactions.TheDSSCbeingtransparentto
some extentandcomparativelycheaperthanconventionalsolarphoto-voltaic,canbeapotentialenergy
source forthefuture.Buttherearemanyaspectsthatneedtobeworkeduponbeforedeclaringitasa
feasible commercialproduct.Thepaperemphasizesontheseaspectsandthevariousimprovementsthat
the DSSChasgonethroughinrecentyears.Thisisadetailedreviewoftheworkdonetoimprovethe
performance ofDSSC,withsupportingdata.Acomparativestudyoftheeffectofvarioussuggested
modification tothedifferentcomponentsofDSSChasbeendone.Thiswouldgiveaclearideaaboutthe
most recentimprovementsdoneinDSSCwithrespecttothevariouscomponents.Itincludesasummary
of thesuggestedimprovementsbyvariousresearchers,bifurcatedintodifferentsectionswithrespectto
the differentcomponentsoftheDSSC.Itwasobservedthatincorporatinggraphenesheetsofvarious
sizes inthephotoanodehelpedtoimprovetheefficiency ofDSSCsignificantly,givingamaximum
efficiency of6.62%.IncaseofnoveldyesusedintheDSSCfabricationtheD-A-pi-Aindolinedyesshowed
a greatenhancementinthecellefficiency,withefficiency ofupto6.9%.IncorporationofPtincounter
electrodes and3D-CEalsoshowednotablygoodefficiency inDSSC,theefficiency improvingupto8.8%.
to serve as a major source of energy, being the only
source having the potential to fulfill the ever increasing
energy needs. Most of the large scale solar farms
employ flat plate photovoltaic concept, so the
installation footprint and shadow effect causes a huge
drop in the electrical efficiency of the system. This
paper aims at developing a methodology to reduce the
area requirements in solar power generation. It
proposes the development of a triangular prism shaped
solar photovoltaic unit, which would reduce the
required area for installation of the panels as opposed
to the conventional method. The paper consists of the
study of a lab level experimental setup of the proposed
model, and comparison of its performance with
conventional flat plate solar cells. The use of reflecting
mirrors within the setup helps improve the efficiency of
the setup, than the panels placed in the same area by
conventional method. It also includes scope of future
development.
radiations (PAR) is useful in various agricultural
applications. However the available measuring instruments
for PAR is generally costly as compared to the lux meter and
not easily available at all places. This paper is an attempt
to establish a relationship between the PAR measurement
and the luminous intensity measurement obtained using lux
meter. Similarly a relation between PAR and the irradiance
is established. A 3-Dimensional representation of the
relation between the photon value, lumens and irradiance
is also obtained. It also includes a report and graphical
representation and analysis produced using the Sigmaplot
software. The future development possible is also included