1. A Seminar Presentation On MAULANA AZAD NATIONAL INSTITUTE OF TECHNOLOGY BHOPAL Presented by-Nitin Paliwal Scholar No.- 222105001

2. 1.Introduction 2.History of Solar cell 3.Use of Quantum dots 4.Solar cell Classification 5.Coating Techniques

3. 1.1888 – Russian physicist Aleksandr Stoletov built the first cell based on the outer photoelectric effect discovered by Heinrich Hertz in 1887. [6] Aleksandr Stoletovphotoelectric effectHeinrich Hertz [6]Aleksandr Stoletovphotoelectric effectHeinrich Hertz [6] 2.1904 – Julius Elster, together with Hans Friedrich Geitel, devised the first practical photoelectric cell Julius ElsterHans Friedrich GeitelJulius ElsterHans Friedrich Geitel 3.1905 – Albert Einstein proposed a new quantum theory of light and explained the photoelectric effect in a landmark paper, for which he received the Nobel Prize in Physics in 1921. Albert Einsteinphotoelectric effectNobel Prize in PhysicsAlbert Einsteinphotoelectric effectNobel Prize in Physics 4.1941 – Vadim Lashkaryov discovered p-n-junctions in Cu 2 O and Ag 2 S protocells Vadim LashkaryovCu 2 OAg 2 SVadim LashkaryovCu 2 OAg 2 S 5.1946 – Russell Ohl patented the modern junction semiconductor solar cell, [10] while working on the series of advances that would lead to the transistor Russell Ohl [10]transistorRussell Ohl [10]transistor 6.1948 - Introduction to the World of Semiconductors states Kurt Lehovec may have been the first to explain the photo-voltaic effect in the peer reviewed journal Physical Review. Kurt LehovecKurt Lehovec 7.1954 – The first practical photovoltaic cell was publicly demonstrated at Bell Laboratories. [13] The inventors were Calvin Souther Fuller, Daryl Chapin and Gerald Pearson Bell Laboratories [13]Calvin Souther FullerDaryl ChapinGerald PearsonBell Laboratories [13]Calvin Souther FullerDaryl ChapinGerald Pearson 8.1958 – Solar cells gained prominence with their incorporation onto the Vanguard I satellite. Vanguard IVanguard I

4.  Quantum dots are semiconductor Nano crystals.  They are made of the same materials as ordinary semiconductors (mainly combinations of transition metals and /or metalloids).  Unlike ordinary bulk semiconductors, which are generally macroscopic objects, quantum dots are extremely small, on the order of few nanometres. They are very nearly zero- dimensional WHAT IS A QUANTUM DOT ?

6. Solar cell classification First generation(Mono- crystalline)- single crystals of pure silicon. First generation(Mono- crystalline)- single crystals of pure silicon. Second generation(Poly- crystalline)- Several crystals of silicon Second generation(Poly- crystalline)- Several crystals of silicon Third generation(Thin film)- A thin-film solar panel is made of thin films of semiconductors deposited on glass, plastic or metels. Third generation(Thin film)- A thin-film solar panel is made of thin films of semiconductors deposited on glass, plastic or metels.

7. Mono-crystalline Advantages and disadvantage of Mono-crystalline Advantages Among all solar panel types, monocrystalline cells have the highest efficiency typically in the 15-20% range. As this solar panel is more efficient so it produces more power. These are having greater heat resistance. In case of low level of sunlight, it can make power. Monocrystalline solar cells can be recycled. As it is made of 3 main components i.e. monocrystalline cells, Glass and Metal. These are all can recycle. Disadvantage These are most expensive. Most monocrystalline solar cells have a temperature coefficient of around -0.3%C to -0.5%C. So when the temperature rises, the monocrystalline solar cell will temporarily lose 0.3% to 0.5% of its efficiency. There is a lot of waste material when the silicon is cut during manufacture.

8. Advantages and Disadvantage of Poly-Crystalline Solar cells The manufacturing process of these panels are cheaper and easier than the monocrystalline cells. The manufacturing process of these panels are cheaper and easier than the monocrystalline cells. These panels have high power density. These panels have high power density. During its manufacturing process, it avoids silicon wastes and requires very few fossil fuels. During its manufacturing process, it avoids silicon wastes and requires very few fossil fuels. These are more eco-friendly than monocrystalline solar panels. These are more eco-friendly than monocrystalline solar panels. These are less efficient between 13%-16%. These are less efficient between 13%-16%. It has lower output rate. It has lower output rate. It needs more roof space for installation. It needs more roof space for installation. They damage easily when exposed to high temperatures. They damage easily when exposed to high temperatures. AdvantagesDisadvantage

9. Advantage and Disadvantage of thin film solar cell. Advantage It is very flexible and can be applicable to a range of situations and building types. It is very flexible and can be applicable to a range of situations and building types. Large no of production is easy to achieve, making them potentially cheaper to produce than crystalline solar cells. Large no of production is easy to achieve, making them potentially cheaper to produce than crystalline solar cells. It can install in shadow area. It can install in shadow area. Disadvantages As they take up a lot of space so it is not good for domestic use. As they take up a lot of space so it is not good for domestic use. It has low efficiency. It has low efficiency. It has shorter lifespan and so shorter warranty periods. It has shorter lifespan and so shorter warranty periods.

10. ParametersMonoPolyThin-film Efficiency15%-20%13%-16%5%-10% Materials usedSingle crystal of siliconSeveral crystal of siliconAmorphous si(thin Si layer) Life span25-30yr20-25yr15-20yr Weight per m^2Higher Lower High temp. performancesDrops 10-15%Drops 20%Drops 0% CostMore ExpansiveLess ExpansiveLess Expensive

11. Why Quantum dots solar cell’s The enhancement of solar cell performance in the infrared region is an important challenge to develop high efficiency solar cells. PbS quantum dots (CQDs) are a promising constituent material for solar cells since quantum confinement effects yield unique optical and electrical properties.  High degree of freedom for controlling exciton absorption band positions.  CQD solid films give a relatively high carrier mobility.  Compatible with low-temperature, solution-based technology.

12. Why use a Pbs Quantum dot? 1.Quantum dot (QD) solar cells have the potential to increase the maximum attainable thermodynamic conversion efficiency of solar photon conversion up to about 66% by utilizing hot photogenerated carriers to produce higher photovoltages or higher photocurrents. 1.Quantum dot (QD) solar cells have the potential to increase the maximum attainable thermodynamic conversion efficiency of solar photon conversion up to about 66% by utilizing hot photogenerated carriers to produce higher photovoltages or higher photocurrents.

13. Colloidal quantum dots (QDs) have been widely studied as absorbers for various solar technologies because of their excellent optoelectronic properties, such as a size-dependent absorption spectrum, efficient charge separation and transport, and good photostability Solution processed coating and printing techniques Spin coating, Dip coating, Spray coating, Slot-die, Inkjet et.al, Solution processed synthesis PbS QD and deposition QD film"

14. Semiconductor Structures Exciton Bhor Radius (nm) Bandgap Energy (eV) PbS 40.0 0.41 GaAs 28.0 1.43 CdTe 15.0 1.50 CdSe 10.6 1.74 ZnSe 8.4 2.58 CdS 5.6 2.53

15. Coating Techniques Coating Techniques 1.Spin coating method 2.Spray coating method 3.Blade coating

16. Spin coating is a method to apply a uniform film onto a solid surface by using centrifugal force and requires a liquid–vapor interface. In a typical procedure, a liquid is placed at the center of a circular surface and is rapidly rotated to produce uniform films of 1–10 μ m in thickness. SPIN COATING METHODS

17. LITERATURE SURVEY S. no Name of the Author/Author’s Title of the paper SummaryRemark 1. Yin-Fen Ma, You-Mei Wang, Jia Wen, Ao Li, Xiao-Liang Li, Mei Leng, Yong-Biao Zhao, Zheng-Hong Lu Review of roll-to- roll fabrication techniques for colloidal quantum dot solar cells This paper reviewed recent studies on the fabrication of large-area CQD solar cells with various roll-to-roll compatible techniques. Amongst, spray coating and blade coating are shown to be promising Journal Pre- proof for producing high-performance CQD solar cells. While other coating techniques, including slot-die coating and dip coating, which have been used for perovskite and organic solar cells, do not attracted much attention in the field of CQD solar cells. The performance of CQD solar cells based on those methods is still low compared with that of other solution-processed technologies, such as perovskite and organic solar cells. There is still a long way to go. However, CQDs are also promising for solar cell applications stract Colloidal quantum dots (CQDs) are of great interest for photovoltaic (PV) technologies as they possess the benefits of solution-processability, size-tunability, and roll-to- roll manufacturability, as well as unique capabilities to harvest near-infrared (NIR) radiation 2. Saim Emin ⇑, Surya P. Singh 1, Liyuan Han ⇑, Norifusa Satoh 1, Ashraful Islam Colloidal quantum dot solar cells Here we reviewed the recent advances in utilizing colloidal quantum dots as light harvesters in various types of photovoltaic devices. At present the power conversion efficiencies of colloidal quantum dot solar cells are about 5%. Further research is needed in this area to screen potential systems which could provide a roadmap for the design of super efficient solar cells. In Abstract In recent years colloidal quantum dots solar cells have been the subject of extensive research. A promising alternative to existing silicon solar cells, quantum dot solar cells are among the candidates for next generation photovoltaic devices.

18. 3.Jung Hoon Song1 and Sohee Jeong Colloidal quantum dot based solar cells: from materials to devices CQDs have been attracting much attention because they can absorb light above their energy bandgap with a high extinction coefcient and can be processed by using a solution process. idal quantum dots (CQDs) have attracted attention as a next- generation of photovoltaics (PVs) capable of a tunable band gap and low-cost solution process. Understanding and controlling the surface of CQDs lead to the signifcant development in the performance of CQD PVs 4. Khalil Ebrahim Jasim Department of Physics, College of Science, University of Bahrain, Kingdom of Bahrain Quantum Dots Solar Cells Crystalline semiconductor solar cells besides possessing low efficiency due to their band gab limit (Shockley- Queisser limit)[53] they are expensive in terms of manufacturing cost per generated Watt of delivered electric power

19. References Review of roll-to-roll fabrication techniques for colloidal quantum dot solar cells 1.Yin-Fen Ma, Review of roll-to-roll fabrication techniques for colloidal quantum dot solar cells, https://doi.org/10.1016/j.jnlest.2023.100189https://doi.org/10.1016/j.jnlest.2023.100189 Colloidal quantum dot based solar cells: from materials to devices 2.Jung Hoon Song and Sohee Jeong, Colloidal quantum dot based solar cells: from materials to devices, https://doi.org/10.1186/s40580-017-0115-0 https://doi.org/10.1186/s40580-017-0115-0 3.Saim Emin, Colloidal quantum dot solar cells, https://doi.org/10.1016/j.solener.2011.02.005 https://doi.org/10.1016/j.solener.2011.02.005 Quantum Dots Solar Cells 4.Khalil Ebrahim Jasim, Quantum Dots Solar Cells, http://dx.doi.org/10.5772/59159 5.https://en.wikipedia.org/wiki/Solar_cellhttps://en.wikipedia.org/wiki/Solar_cell 6.https://solarismypassion.com/solar-blogs/type-of-solar- panels/?_gl=1*dflo9u*_ga*V0c1RFFHX1N1UHRpa3Etc2N3MGo5QURINkwzWWRPZVJ CSzRaMXZrRzBhVGZ5dUtCSkN4SVhTSmlrWWpYT25Uaghttps://solarismypassion.com/solar-blogs/type-of-solar- panels/?_gl=1*dflo9u*_ga*V0c1RFFHX1N1UHRpa3Etc2N3MGo5QURINkwzWWRPZVJ CSzRaMXZrRzBhVGZ5dUtCSkN4SVhTSmlrWWpYT25Uag 7.https://www.solarsquare.in/blog/types-of-solar-panelshttps://www.solarsquare.in/blog/types-of-solar-panels

20. References