This thesis is proposed to deal with entirely new compound semiconductor materials that provide a significant stock of prospective to be used in the energy systems like photovoltaic (PV) solar cells. Cu2ZnSnS4, which is denoted as ‘CZTS’, nearly associated to a class of materials used in advanced making for photovoltaic (PV) applications from late 1969.
In this day and age, energy consumption globally is at the rate of y4.7multiply 10 20 joules per year. That is analogous to the global utilization of the power of y15 terawatts (TW) as the population in the world is continually growing by the massive amounts. The necessity of humans for the demand for energy rises and seemingly by the end of 2026. Now it can be estimated to increase two times more than that of now. Requirement of energy by humankind, the mandate is commonly fulfilled through the coal, oil, and many nonrenewable resources which are inadequate. The fossil fuels burning also produces environmental pollution by the draining of natural gases, for instance, carbon dioxide, oxides of nitrogen, CO, Sulphur dioxide, etc. Solar energy is accepted to play an essential starring role in the future energy development of the world that provides the benefits to solar‐to‐hydrogen through attaining a clean energy transporter. Hydrogen is a viable energy carrier, accomplished for replacing fossil fuels and reducing carbon dioxide (CO2) emission to protect the domain from global warming. Solar energy is pollution-free and richly exists. Solar energy consumes sunlight to give heat, light, electricity, etc. for native and industrial usages.
Consequently, the necessity of the present time demand to discover and make the most renewable, ecologically energy resources from the environment, which would cause the modification of the conservative energy resources that can never be deleted from the environment, and these resources can be used again and again. Among the various renewable energy sources that are discovered up till now, solar energy is among the best plentiful, safe, and productive renewable energy resources for humankind. With the growing utilization of conservative energy and the slowly but surely severe ecological dilemma, the work and use of solar cells fascinated global responsiveness. In the recent decade, the advancement of the TF research technique stimulated the era of solar cells of second-generation technology of this second generation solar cells created on semiconductor materials of TF to develop. The request for small scale material, the TF solar cell technique can efficiently decrease the budget of materials. Furthermore, the materials of TF can adaptably be installed on the surface of substrates like steel which must be stainless, glass, and the polymer of plastic, particularly appropriate for the construction of solar incorporation. CZTS is regarded as the ideal material for absorption for the future generation solar cells of TF owing to critical constituent elements in the earth crust’s as non-toxic and ecologically appropriate.
Statement of the Problem
The continuing upsurge in the world’s energy demand and the lack of the existing conventional energy sources, much more focus is shifted on the usage of other renewable energy resources like wind energy and solar energy. A solar cell is designed in a way to uses the photovoltaic effect to transform the light energy into electrical energy. Extensively used solar cells that are in use nowadays are of silicon type that is crystallized, which deals with a transformation efficacy of 15 to 20%. The foremost disadvantages of the type mentioned above of silicon photovoltaic (PV) cells are that they are costly and incline to breakdown quickly. The usage of polycrystalline silicon for photovoltaics is not so costly and readily available and also provides more muscular cells; however, the conversion efficacy is about 10 to 14 percent. Thin-film solar cells have increased responsiveness in the current time because thin films can be attained by this method at much less construction cost. Though, they undergo the disadvantage of low conversion efficacy.
Amongst the thin films considered for use in photovoltaic solar cells, amorphous silicon, cadmium telluride (CdTe) and copper indium dieseling (CuInSe2) are of great significance. But, Cd is toxic, and the production of CuInSe2 includes the release of enormously toxic hydrogen selenide. As a way out to these complications, the study on the use of Copper, Zinc, Tin, and Sulphur (CZTS) thin films for photovoltaic applications has gained much attention. Copper (Cu) Zinc (Zn) tin (Sn) sulfide (S) which is commonly known as CZTS that proved one of the best choices with a bandgap of about 1.4 to 1.5electron Volts and co-efficient of absorption is 104 cm to 1. The construction of the thin film of Copper Zinc Tin Sulphide does not include the release of any toxic gas and the raw materials included are ample on earth. Existing conventional energy sources, much more focus is shifted on the usage of other renewable energy resources like wind energy and solar energy. A solar cell is designed in a way to uses the photovoltaic effect to transform the light energy into electrical energy. Extensively used solar cells that are in use nowadays are of silicon type that is crystallized, which deals with a transformation efficacy of 15 to 20%. The foremost disadvantages of the type mentioned above of silicon photovoltaic (PV) cells are that they are costly and incline to breakdown quickly. The usage of polycrystalline silicon for photovoltaics is not so costly and readily available and also provides more potent cells; however, the conversion efficacy is about 10 to 14 percent. Thin-film solar cells have increased responsiveness in the current time because thin films can be attained by this method at much less construction cost. Though, they undergo the disadvantage of low conversion efficacy.
Amongst the thin films considered for use in photovoltaic solar cells, amorphous silicon, cadmium telluride (CdTe) and copper indium dieselize (CuInSe2) are of great significance. But, Cd is toxic, and the production of CuInSe2 includes the release of enormously toxic hydrogen selenide. As a way out to these complications, the study on the use of Copper, Zinc, Tin, and Sulphur (CZTS) thin films for photovoltaic applications has gained much attention. Copper (Cu) Zinc (Zn) tin (Sn) sulfide (S) which is commonly known as CZTS that proved one of the best choices with a bandgap of about 1.4 to 1.5electron Volts and co-efficient of absorption is 104 cm to 1. The construction of a thin film of Copper Zinc Tin Sulphide does not include the release of any toxic gas and the raw materials included are ample on earth.
In the present research work, the primary purpose behind this is to enhance the process of electrical dispositioning on the elastic surface of substrates to acquire a great feature thin film of CuZnSnS. All depending on the foundation of the knowledge developed by research scientists for the fabrication of thin film of Copper Indium Gallium Selenide and by electrical deposition.
1.3 Relevant Literature
With time, the energy necessity is rising beyond the parameters as the rate of growth exceeds a profound thoughtful significance because there is a population pressure is increasing every year. The consumption of energy in fabricating novel methods exceeds the conduction of energy to those systems of that area . Electricity is the chief elastic and appropriate energy. On the other hand, electricity is not only a crucial phase of energy. Electricity can be produced by many other forms of energy resources just as biomass, petroleum, wind energy, hydrothermal, geothermal energy, sunlight, tides in deep-sea or tidal energy, bio-mass, atomic emission, energy cells, natural gasses from dead matter . The non-stoichiometry of composite semiconductors at all times draw a parallel associated with the electrical characteristics of these semiconductors.
In the recent decade, the advancement of the TF research technique stimulated the era of solar cells of second-generation technology of this second generation solar cells created on semiconductor materials of TF to develop. The request for small scale material, the TF solar cell technique can efficiently decrease the budget of materials. Furthermore, the materials of TF can adaptably be installed on the surface of substrates like steel must be stainless, glass, and the polymer of plastic, particularly appropriate for the construction of solar incorporation. CZTS is regarded as the ideal material for absorption for the future generation solar cells of TF owing to critical constituent elements in the earth crust’s as non-toxic and ecologically appropriate.
Cyclic voltammetry in Electrodeposition is the most attractive technique used in an
electrochemical deposition. The standard system of the three-electrode cell was implied for the cyclic voltammetric trials. Thin-film solar cells have increased responsiveness in the current time because thin films can be attained by this method at much less construction cost. Though, they undergo the disadvantage of low conversion efficacy.
1.3.1 Solar Energy
With the passage of time, there is an increase in energy demand, and also we are facing a shortage of energy resources. There is a continuous depletion in energy resources. Solar energy is the form of light energy coming from the sun. Most of this energy is captured by plants for photosynthesis, but this form of energy can also be used in place of nonrenewable resources. There are many techniques that can be used to convert solar energy directly or indirectly into electricity. The primary transformation technology is the photovoltaic solar system. This cell works as an electrical instrument that transforms the energy coming through light from the sun into electrical energy directly through the effect of PV. A physio-chemical process and its voltaic features, such as current, resistance, or current, changes upon exposure to sunlight. Solar energy causes no pollution, so it is a pollution-free source of energy and is abundantly available in nature. Solar energy uses sunlight to provide heat, light as well as electricity for domestic, commercial, and industrial uses.
Solar energy is accepted to play an essential starring role in the future energy development of the world that provides the benefits to solar‐to‐hydrogen through attaining a clean energy transporter. Hydrogen is a viable energy carrier, accomplished for replacing fossil fuels and reducing carbon dioxide (CO2) emission to protect the domain from global warming. Solar energy is pollution-free and richly exists. Solar energy consumes sunlight to give heat, light, electricity, etc. for native and industrial usages. With the frightening decrease of significant energy resources such as coal, petroleum, and gas, along with the environmental lack caused by the process of binding these energy sources. It has become a compulsion to exploit renewable energy resources that would power the upcoming energy needs sufficiently deprived of humiliating the environment through greenhouse gas discharge .
1.3.2 CZTS Solar cells, properties, history, and device efficiencies
CuZnSnS is the I2–II–IV–VI4 quaternary compound semiconductor by replacing the Se with S, the rare metal In with Zn, and Sn in CIS ternary compound. Each constituent of CZTS is ample in the crust of the earth (Copper: 50.0 ppm, Zinc: 75.0 ppm, Tin: 2.20 ppm, Sulfer: 261 ppm) and they retain very less toxicity. On the further side, in the case of the CIS compound, the amounts of In and Se in the earth’s crust are 0.05 ppm or a smaller amount . Earth profuse Copper-zinc-tin-chalcogenide (in this communally denoted as CZTSSe) thin films have fascinated growing consideration for photovoltaic applications. Manifold vacuum and non-vacuum established thin-film installation techniques have been testified for the preparation of CZTSSe thin films . Cu2ZnSnS4 (CZTS) quaternary semiconductor has arisen as a capable applicant for the solar absorber materials. All the components of CZTS are low cost, less toxic, and earth plentiful. The earth stuffing of elements used in CZTS, CIS, CIGS, and CdTe light absorbers is shown in Fig. 1. The prospective of CZTS was documented about 20 years ago by Ito and Nakazawa, who organized films by atom beam sputtering of a synthetic CZTS powder source and proven a photovoltaic effect at the junction between CZTS and cadmium-tin-oxide
Chemical and physical properties of CZTS
CZTS is composed of four materials, including zinc, Copper, Sulfur, and Tin. CZTS is a quaternary type complex semiconductor that refers to stannite structure, and its chief constituent which is the combination of two forms containing zinc and iron. Usually, stannite grants steel grey color with small shining metallic colors like olive green, which is generally in the vast particle form. It primarily takes place in some regions of the UK, i.e., Cornwall and Bolivia, in the form of hydrothermal deposits. In 1960, a scientist had anticipated a stannite structure containing iron in place of zinc (Copper iron tin sulfide) semiconductor of quaternary structures of ultra-crystal written in the journal ‘Nature’. Until 1974, it’s not the first time that two scientists Schafer and Ritchey had made-up CZTS up to that era. Another chemist offered that only one phase of Copper Zinc Gallium sulfide existed there which is present in the complex of this system and also two transitional stages of quaternary type. And the iso-thermal segment of the two systems used was created by using the technique of X-ray diffraction at 670 K for analysis.
The non-stoichiometry of composite semiconductors at all times draw a parallel associated with the electrical characteristics of these semiconductors. To achieve high proficiency Copper Zinc Tin Sulphide solar cells, now there is a practical instruction that the Copper: (Zinc + Tin) and Zinc: Tin atomic ratios ought to be from the range of 0.74 to 1.0 and 1.0 to 1.252, correspondingly. The Copper: (Zinc + Tin) and Zinc: Tin ratios are 0.59 and 1.10, individually, for the originator thin films, and 0.70 and 1.20 for the sulfurized thin films of Copper Zinc Tin Sulphide. The Copper: (Zinc + tin) and Zinc: Tin ratios of the thin films of the CZTS are a little higher than that those of the originator thin film. That is endorsed to the emission of tin all through the addition of sulfur.
1.3.4 Procedures for manufacturing of thin-film (TF) constituents
In broad-spectrum, the methods applied to formulate TF plunge into two classifications, which are by the name as “single-stage” and the second as “two-stage”. According to the name, single-stage procedures are those who manufacture the whole crystal film in a single step. For instance, the co-evaporation of the components on top of substrates that are heated made 30 of the most beautiful devices to era, even though fascinatingly it is quite different in the case of CZTS.
The primary step is the grounding of a ‘predecessor’, that is in general formed at room temperature, and comprehends any (a) merely the metal type elements (b) all the un-reacted or non-crystalline element forms. While performing the second stage, the predecessor is heated, typically in an aerobic way comprising a source of sulfur (5). That is termed as ‘sulfurization’ / ‘salinization’. The development and crystallization of the preferred phase from the predecessor film have opted at heating. The use of the first stage in an abundant variety of different means can be conceded, examples included from the CZTS collected works are pulsed, deposition, sputtering and electron beam evaporation, electrodeposition, nanoparticle or suspension printing as well as spray pyrolysis.
1.3.5 Preparation of CZTS Thin Film by electrochemical deposition
One of the most attractive techniques, in this case, is electrodeposition which is used for the little cost development of various semiconductor thin films on a small scale in research work as well as on broad-scale application in industries.
The specific deposition procedures smeared for the production of thin films of CZTS (atom beam sputtering, photochemical deposition, thermal evaporation, electron beam evaporation, hybrid sputtering, pulsed laser deposition and screen printing,) involve complex apparatus which is very costly. In the field of electrochemical deposition, the path gives the idea of great attention because it is straightforward to perform. It is without vacuum, and this is a very cheap technique, that can be operated at standard temperature and utilizing the solvents of less toxicity and chemical agents, which have very high output as well as the consumption of large materials. Also, electrochemical deposition which has the benefit of being a technologically proven procedure for massive field area semiconductor electrochemical deposition of higher homogeneity in the arrangement. By the way, up till now, the relevant literature shows its composition which is non-uniform and the occurrence of other phases inhibit the acquisition of electrochemical deposition of thin films of CZTS is of great value. Now at the present work, the primary purpose of boosting the electrodeposition procedure for the flexible substrate in command for getting the best quality of thin films of CZTS.
To decrease the positive ions in the water solution, carbon-based solution, or heated liquid in the negative electrode by providing potential difference together with the external power circuit, the electrochemical deposition coating process is used for this purpose. In the middle of 1970, the general public initiated the process of electrochemical deposition of materials with semiconductor nature. At this moment, the electrochemical deposition procedures have been so far and wide engaged for the manufacture of PV solar cells, such as the Copper Indium Gelinium Selenide solar cells. Even though Cadmium selenide in the electrochemical deposition has used the thiourea as predecessors, that became to be very challenging to discover like a constant source of sulfur in the electrochemical deposition of CZTS. In the late of the year 2008, the University of Bath in Britain use another method of coating and vulcanizing the electrochemical deposition of Copper, Tin and Zinc to achieve the CuZnSnS solar cells with a transformation efficacy of about 0.8 percent. Far along, they expanded the solar cells with a transformation efficacy of about 3.16 percent over and done with the one-step co-deposited in the alloy of Copper Zinc and Tin and at that moment hardening for two about hours at the highest temperature of 600 degree Celsius in the gas having some sulfur molecules in powder form.
Regardless of these quick enhancements, the amount of comprehensive investigational researches of the simple characteristics of CZTS happened to somewhat inadequate; most data is focused on the fabrication of devices instead of attaining a considerate thought of the material inherently.
Transfer an electron in the solution; there should be easily reducible ionic species. For example, in the case of electrochemical deposition, metal cations containing solution is provided, electron transform product results from the electrode-solution interface are an insoluble compound, that must have adhered to the electrode. By taking the example of Copper electrochemical deposition from an electrolyte containing the solution of copper and sulfate, the electrical deposition method at the cathode (negatively charged electrode), which is a reduction reaction, which is given as:
Cu2+(aq )+ 2eà 2 Cu0(s)
The negative ions of sulfate do not take part in the electric chemical deposition reaction. Still, their movement from the negatively charged electrode to the positively charged electrodes favors the flow of current in the solution. Meanwhile, the material used in electrochemical deposited is conductive itself, the reaction will not stop, and proceeds as the potential difference of electrodes is maintained. In the solution, the concentration of copper ions (Cu2+) will so progressively decrease unless these ions are reloaded. In the circumstance of any industry, the anode (positively charged electrode) is frequently prepared from the same metal, in this case, there is copper, and the reaction occurs reversibly.
The Copper ion concentration in the electrolyte is kept constant in this case. A thin film of copper grows on the surface of the substrate at the negatively charged electrode (cathode). In contrast, the copper at the positively charged anode progressively becomes soluble and dissolves in the solution.
1.4 Factors affecting Electrodeposition
A confounding factor in electrical deposition from water solutions is that water inherent analogous abilities to most of ions. Results in the progression of H2 (Hydrogen) gas from the operational electrode in the electrolyte solution. In the case of acidic and basic pH solutions, the hydrogen evolution reactions (HER) are revealed here:
H + (aqueous) + e––à ½H2 (g)
H2O + e–—à ½H2 (g) + OH–(aqueous)
The average decrease in the impending HER is described as 0 Volt in comparison with the Normal Hydrogen Electrode (NHE), but the possible practical variations in pH.
Table 1.1 Hydrogen overpotentials dynamic to attain hydrogen evolution at a charge of 1mA cm-25for some appropriate substrate constituents
Just like the HER, there might be some other procedures limiting the variety of possibilities for a particular system to be used. For instance, water oxidation that takes place, which has similar actions to the hydrogen evolution rate but provides current from the anode, and an additional prospect, is the oxidation process to happen in the material of the substrate. That possibly will create a loss of electrical power at the base that should be fled away .
1.5 Cyclic voltammetry
The electrochemical deposition of electrolytes such as Copper, Tin, and Zinc are examined through the cyclic voltammetric process.CV involves perusing the potential that is used by the operating electrode at a uniform rate when the potential limit exceeds at five the direction of the scan draws back; this procedure allows us to measure the current flow. For instance, an originating point, we think the current is flowing has potential, which is zero.
According to the condition, when the electrode-solution edge is at the level, there are an equivalent and clashing transmission of ionic molecules or ions transversely. The exciting Helmholtz Layer – dynamic type equilibrium is recognized by redox reactions that takes place at the same rate. In the meantime, there is neither net chemical alteration nor the net current.
On behalf of this reaction Mz+ + 2eà M0, the potential by which this equilibrium is established is showed by the standard reduction potential as E0M and is well-organized under normal conditions like average room temperature, concentration, and atmospheric pressure about the standard hydrogen electrode reference. If the quantity of solution and the electrolyte temperature and pressure are varied from standard values, then the actual potential for 0 current flow changes far from E0M, which is by the Nernst equation.
2.1 Research Design and methodology
CZTS thin films were electrodeposited at a constant voltage on Indium Tin Oxide (ITO) substrates sustained by the polyethylene terephthalate (PET). Former to Electrodeposition, pre-treatment of substrate involving in a process which is called ultrasonic cleaning, which is used for organic solvents. (1st step: propanone, 2nd step: alcoholic isopropyl compound, for about 15-20 minutes for every step) was take on . It is accomplished to get hold of regular deposits. Electrochemical depositions were conceded at a constant voltage under N2 atmospheric pressure at room temperature from an aqueous solution with no air comprising Copper sulfate (0.01M), Zinc sulfate (0.01M), tin sulfate (0.02M) and Na2S2O3 (0.2M).To improve the stoichiometry of the electrochemical deposit, electrochemical deposition baths associated with changed conformations, gotten mingling at varied capacities of the mixture mentioned above, were all examined. The ideal pH was close to 5.0, which was achieved by adding an acid (usually lactic acid) and sodium hydroxide (10M). The electrochemical deposition was accomplished for about 45 minutes, at a potential of about -1.055 Volts; electrochemical deposition testing was executed by utilizing a potentiostat (model number PARSTAT-2273). A typical three-electrode cell that was used, with a platinum net as hostage conductor and the SCE by way of reference. Structural analysis was done by the usage of the scanning electrode microscopy (SEM), using a particular gun that is called field-emission gun (FEG) for biological scanning electron microscope (the model number of QUANTA-200F) equipped with EDS. For the development, it should be sure about the trustworthiness of the varied depictions that were done on different parts of the unchanged sample. Then the Films were regarded through the X-ray diffraction analysis, by the usage of an Ital Structures (model no. APD2000) diffractometer devising the Copper Kα rays (λ= 0.15 nanometer) as the reference, at a stage of 0.02 degree and a calculating time of 0.50s for step respectively.
Photoelectrochemical behavior of electrochemically CZTS deposited thin films. It was studied at average temperature in a ventilated solution of 0.10M Na2SO4 by using a three electrodes-cell, in which there are platinum (Pt) net and one electrode as the counter and the other standard electrode of mercury sulfate electrode as a reference. These cells were fitted out together with windows of quarts for letting the illumination from the sample, attained by utilizing a lamp of 150W Xe(Oriel) combined to Ultraviolet or visible mono chromate device (Bausch and Lomb), which is attached to the optical line together with quartz optics. The Photocurrent was identified by two-phase lock-in (EG & G, model 5206), which is associated with a mechanical chopper (with a frequency of about: 10 Hz). A yellow filter was introduced in the way of light just before calculating the Photocurrent through large wavelengths to inhibit second harmonic comebacks.
2.1.1 Cyclic voltammetry in Electrodeposition
Cyclic voltammetry in Electrodeposition is the most attractive technique used in an
electrochemical deposition. The standard system of the three-electrode cell was implied for the cyclic voltammetric trials. The Platinum rod of about 2mm in diameter was utilized by the operating electrode, the platinum mesh electrode was employed in place of another electrode, and Silver/Silver chloride electrode was utilized using the electrode which is being used as a reference. CuS, stannous S, and ZnS (Zinc Sulphate) were used as per the cause of Copper, Tin, and Zinc, respectively.
he quantity of every element used was different from 2.5mM to 7.5mM. 100mM lithium chloride was utilized in all experiments is the most common electrolyte, and tri-sodium citrate was utilized instead of the agent whose nature is complexing. The quantity of this agent was static at 25mM. As well, cyclic voltammetry experiments in the prepared blank solutions lacking tallying the copper, tin, and zinc constituents which were accompanied to discriminate the reactions without those constituents. There are two new solutions of different types, a 100mM lithium chloride solution and a 100mM lithium chloride by the addition of 25mM tri-sodium citrate was organized. The pH of the developed electrolyte was utilized and well-ordered at 4.7 with H2SO4 and NaOH. The cyclic voltammetry trials were accompanied by an open-circuit voltage (OCV) from a negative direction first in a positive direction and in conclusion, completed at the open-circuit voltage.
Results are the final intention of scientific research: here you condense the data composed and the statistical treatment of them. The interpretations and measurements note down despite the fact directing the procedures defined in the methods section must report the questions rose in the introduction, and any hypotheses put into words there.
3.1 Profile and Statistics of Respondents
Results are frequently accessible in numerical form and are more worthy of a read if presented graphically in tables and graphs.
3.2 Reliability of Individual Influence Scales
The foremost risk features impacting the sternness of road traffic damages and road safety concerns.
4.1 Morphological Studies of CZTS by SEM
he scanning electron microscope was used to examine the properties based on the morphology of the contained samples. Fig. Three displays constant film with massive particles were shaped on or after the accumulation of minor nanoparticles Copper Zinc Tin Sulphide. SEM displays the thin film as a dense part in structural properties deprived of somewhat cavities and different crashes. However, with present some irregularity. For getting hold of high efficacy solar cells, very high-temperature action is crucial to upturn the crystal-like form and particle size of films of CZTS. The effectiveness of the complex structure of polycrystalline solar cells rises with a surge in the particle size of the layer that is absorbed. The morphological studies of the surfaces of thin films will be varied dependent on distinct mass order in ancestors/
For the advanced stage in the electrodeposition, we detected that the thickness of the film higher than before slow. Possibly it was triggered by amplified resistivity of the electrolyte and the reduced kinetics of the reduction of the ions. Above and beyond, the lower percentage of thickness incrementing the later stage of electrodeposition may be owed to less accessibility of the species present in the bath. As a result, the thickness of the TF could be easily organized in an appropriate variety. The abridged atoms are likely to fill in the lowest point and trenches to form an even and uniform surface because of the flattening effect of the additives.
4.2 Structural Studies of CZTS by XRD
The X-ray diffraction studies showed the development of kieserite phase CZTS in the deposits. The crystal structures of the previously manufactured nanostructures of CZTS were studied through X-ray diffraction technique and x-ray diffraction measurements. Fig.4 displays the X-ray diffraction patterns of the previously manufactured CZTS nanoparticles set down by electrodeposition with 2-degree theta scanning from 20 degrees to 80 degrees. X-ray diffraction measurement displayed crests are ascribable for CZTS was (112), (220), (132), (224), and (332). The film that was detected to be full-grown with noble crystalline form. The stage illustration was piercing for the occurrence of Copper Zinc Tin Sulphide with the Structure of the kieserite with number one alignment on the (1-1-2) plane that is in settlement for the other information.
The experiments which are performed, do not allow us to identify the nature of complicated defects. It indicates the defects in shrinkage in the band gaps. The composition in CZTS thin-film development is controlled by the modification of amounts of tin and zinc sulfide.
4.3 Cyclic voltammetry studies of CZTS
As it is noticed, the CV can provide a vast number of characteristics into the reduced measurable statistics about the system at the pointer, as well as the electric chemical deposition gaps, the (initial) rate of the metal declines as the purpose of pragmatic potential along with the predictable standard potential value. Quantities at varied scan amounts used to conclude also the diffusion coefficient of the metal ion along with the transfer coefficient α. Fig. Five depicts the deposition potentials were found to move on the road to the right with the rise in pH.
Conclusion segment relocates the aim of conducting research, enlightening synopsis that founded to leading into allegations of outcomes. A conclusion might also comprise restrictions of the study and further new research prerequisites.
5.1 Aim of this project
As a conclusion, the thin films of CZTS is a 3rd generation one of the most important materials for photovoltaic solar cells. It is very important to obtain high-quality thin films of CZTS with good properties at room temperature that is obtained without the second phase. The thin films of CZTS have been developed by the process of sulfurization of electrochemically deposited constituents of CZT on the substrate of Mo coated glass. The main purpose of this project to explain the preparation of feasible thin films of CZTS from the process of sulfurization (treatment with sulfur) of electrochemically deposited thin films of Copper (Cu), Tin (Sn) and Zinc (Zn). The development of these tin films involves a process which is discussed in chapter 2. This technique allows us to control the composition of constituents used in the formation of tin films of CZTS. And the rotating disc of the electrode system is also useful to maintain the uniformity in the composition of constituents.
Thin films of Copper (Cu), Selenium, Zinc (Zinc), and Tin (Sn) were developed as CZTS constituents or precursors and converted to thin films of CZTS by the process of sulfurization. X-ray diffraction technique measurements have proved that the process of sulfurization eliminates all the second phases. Cyclic voltammetry technique was also used for the analysis of reduction behavior of copper, zinc, and tin. In this process, tri-sodium was used to decrease the difference in reduction potential of all materials. This change allows the formation of tin films of CZTS from Copper, Selenium, Zinc, and Tin mixed only a single bath through the electrochemical deposition method. During the development of thin films of CZTS, an inert gas is introduced to avoid the formation of some oxidized compounds that may form in the structure of thin films of CZTS. This shows that quaternary electrochemical deposition is a very suitable process for the development of tin films of CZTS as a very important application in devices with photovoltaic (PV) activity. All these important findings are of very great value that indicates good quality electrochemically deposited thin films of CZTS can be successfully developed by very simple and less expensive procedures like electrochemical deposition. Further researches are in progress utilizing various substrates.
5.2 Managerial Implications
The managerial suggestion offers remarks and proposals for further research and practical service. Illustrate and sell your results. Demonstrate your suggestions and recommendations. Reference example of thesis/dissertation, conference paper, and e-monographic material.
5.3 Research Implications
The thoroughgoing significant portions of a research article are the explanations, evaluates, and clarifications of the data. Here you state the implications of the findings. The investigation desires to recognize for the student to know the reason and to examine in what way the analysis and explanation were prepared and in which manner the main ideas in the analysis were forward. Furthermore, the student prerequisites to notify the person who reads his unpredicted results and arrangements which arose from the research data shows a sort of indication to upkeep statements and analyses concluded. To tell about the results you made depicts is the paramount way for your reader to be acquainted with what you have exposed. Quotation marks, essays, articles, work models, and any other facts can be used for the provision of clarifications or declarations.
5.4 Future Directions
At present, photovoltaic solar cells which are based on thin films of CZTS have reached conversion efficacy of power around 10 percent, now the efforts are putting them very close to the record up to 11 percent. The relative abundance of copper, zinc, and tin stance as firm competition for the prevalent adaption of thin films of CZTS solar cells. This fabrication technique offers high performance, easy development method, and long term stability of the device are becoming the most dominant thin-film technology for future generation solar cell development.