IMPROVING THE PERFORMANCE OF MONOCRYSTALLINE SILICON PERC SOLAR CELLS BY OPTIMIZING FRONT AND REAR METALLIZATION

2022-6
Asav, Hasan
Silicon photovoltaics dominates the solar cell market, accounting for over 95% of the total share. The fabrication process of silicon solar cells includes some crucial steps that have a significant impact on solar cell conversion efficiency. These steps are mainly categorized as surface texturization, diffusion, antireflective coatings, and metallization. Among these crucial steps, metallization is a key step for the reduction and control of the electrical and optical losses of the solar cell. The formation of the electrical contacts is achieved by the metal layers on the front and back surfaces of the solar cell. In this M.Sc. thesis, optimization of the metallization is studied for passivated emitter and rear contact (PERC) solar cells to improve cell performance. Rear side metal contact formation for the PERC solar cell is strongly linked with the laser contact opening (LCO) process which provides a path from the rear surface of the cell to the silicon substrate. Therefore, optimization of LCO is a necessary part of the study to minimize the losses from the rear passivation stack. With this aim, different LCOs are studied and the optimum metal fraction for the rear side is performed on the fabricated PERC solar cells. An average of 6 mV cell Voc increase is gained thanks to these optimizations on the rear side. The metallization process in this study is based on a screen-printing method for the formation of front and rear metal contacts of the PERC solar cell. A GriddlerPro simulation program is utilized to design and simulate the front metal design. Then, the analysis of front metal contacts is done thoroughly. After these optimizations, the fast-firing step is studied and a newly developed recipe is brought to the ODTÜ-GÜNAM laboratories. While new cell designs are rapidly growing, our future goals will include following these new advances closely and employing new metallization schemes that can enhance cell performance.

Suggestions

OPTIMIZATION OF EMITTER LAYER IN N-TYPE BIFACIAL CRYSTALLINE SOLAR CELL
Salimi, Yasaman; Turan, Raşit; Ünalan, Hüsnü Emrah; Department of Micro and Nanotechnology (2022-5-09)
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 ...
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...
Optimization of fabrication steps for n-type c-Si solar cells
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 ...
Improvement of silicon heterojunction solar cell performance with new surface structure and wide band gap carrier selective layers
Dönerçark, Ergi; Turan, Raşit; Yerci, Selçuk; Department of Micro and Nanotechnology (2021-10-15)
The photovoltaic (PV) industry is dominated by silicon-based solar cells owing to the abundance of silicon and its full-fledged technology. The main road for the PV industry points out to enhance the conversion efficiency of solar cells while decreasing production costs, which is crucial for improving renewable energy market share. The silicon heterojunction solar cells (SHJ) are receiving attention on this road map due to their higher conversion efficiencies, simple process flow, and low-temperature fabric...
Effects of different laser modified surface morphologies and post-texturing cleanings on c-Si solar cell performance
Radfar, Behrad; ES, FIRAT; Turan, Raşit (Elsevier BV, 2020-01-01)
Performance of crystalline Silicon solar cells depends on numerous factors. One key factor is a surface structure which can restrict electrical and optical properties due to recombination of generated carriers and reflection of incident light. Surface texturing reduces reflection from a flat surface which increases absorption of light. Anisotropic alkaline etchants are commonly used for texturing mono-crystalline Silicon wafers which produce pyramid structures on the surface. Because of randomly oriented cr...
Citation Formats
H. Asav, “IMPROVING THE PERFORMANCE OF MONOCRYSTALLINE SILICON PERC SOLAR CELLS BY OPTIMIZING FRONT AND REAR METALLIZATION,” M.S. - Master of Science, Middle East Technical University, 2022.