Salimi, Yasaman
P-type solar cells currently hold most of the market share in industrial solar cell fabrication statistics. NREL's highest efficiency record for p-type crystalline perc cells is 22.8%. However, there is an ever-increasing interest in n-type wafers due to the many advantages they have against p-type cells. According to the ITRPV's estimation, the n-type cell structures will be taking half the industry's share by 2031. Compared to p-type cells, n-type cells yield better efficiency and lifetime values and are not affected by boron-oxygen defect and light-induced degradation (LID). However, the processes of boron emitter doping and passivation in this cell type can be challenging. Also, a boron-rich layer (BRL) forms during the boron doping process. Due to the high density of inactive boron atoms, BRL acts as a high carrier recombination site. As a result, it is essential to effectively remove and replace it with another layer that effectively passivates the emitter surface. Therefore, the primary work of this thesis is to optimize the boron doping recipe resulting in uniformly doped emitter regions. Various thermal and chemical oxidation recipes were tested and optimized. Different passivation stack layers were also tested in order to achieve the best imp Voc results. The firing temperatures were optimized, aiming to achieve good contact resistivity values while preserving the imp Voc. Finally, the bifacial solar cell was produced utilizing the optimized values as a proof of concept. The fabricated cells have been characterized and analyzed with an efficiency of 18.2% and a Voc of 0.631 V.


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Salimi, Arghavan; Turan, Raşit; Department of Micro and Nanotechnology (2019)
Silicon based solar cells are the dominant type of solar cells in the photovoltaic industry. Recently, there have been increasing efforts to develop c-Si solar cells with higher efficiency and lower cost. Among them, silicon heterojunction solar cell (SHJ) is attracting much attention because of its superior performance values demonstrated at both R&D and industrial levels. One of the common limiting criteria is the recombination at the front side which can be solved by providing proper passivation at the f...
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Orhan, Efe; Ünalan, Hüsnü Emrah; Department of Metallurgical and Materials Engineering (2019)
Crystalline silicon (c-Si) solar cells fabricated on p-type wafers are still dominating the photovoltaic (PV) industry due to advantages in device processing and early focus on p-type cells in the development phase of the industry. Over the years, studies on n-type Czochralski (CZ) substrates have shown that they can be more desirable for the terrestrial applications due to superior material and process advantages such as higher minority carrier lifetime, easier passivation of the surface, absence of light ...
Optimization of laser processing for PERC type c-Si solar cells
Genç, Ezgi; Turan, Raşit; Department of Micro and Nanotechnology (2019)
Passivated Emitter Rear Contact (PERC) type solar cells, which currently owns a similar market share as the standard type solar cells, is expected to be the dominant type of the photovoltaic (PV) market in near future (ITRPV, 2019) due to its high performance/cost ratio. Hence, it is critical to optimize PERC process steps to achieve higher efficiencies. In PERC concept, the stack of a passivation layer and SiNx capping layer is locally ablated to form low recombination and low resistive contacts. In this w...
Beyond 3rd generation solar cells and the full spectrum project. Recent advances and new emerging solar cells
Akınoğlu, Bülent Gültekin; Badescu, Viorel (2021-08-01)
Solar cells have over 50-years of development history; many different devices and technologies are studied over this time span, and interestingly it is still a hot research topic. Although the physical mechanisms involved in photovoltaic processes are rather fundamental, the characterization and classification of the research pathways seem complicated and can even lead to misleading argumentation. Various photovoltaic devices are classified as first, second- and third- generation based on the developments f...
Fabrication and characterization of PEDOT:PSS hole transport layers for silicon solar cells
Türkay, Deniz; Yerci, Selçuk; Department of Micro and Nanotechnology (2019)
Heterojunction silicon solar cells have gained considerable interest in recent years with the demonstration of record-high device performances. However, these devices are typically based on inorganic layers fabricated at high temperatures under vacuum environment, using toxic precursors. The low temperature budget, non-toxic chemical contents, and wide range of adjustability in physical and electrical properties make poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) a promising candidate a...
Citation Formats
Y. Salimi, “OPTIMIZATION OF EMITTER LAYER IN N-TYPE BIFACIAL CRYSTALLINE SOLAR CELL,” M.S. - Master of Science, Middle East Technical University, 2022.