Optimization of metalization in crystalline silicon solar cells

Demircioğlu, Olgu
Production steps of crystalline silicon solar cells include several physical and chemical processes like etching, doping, annealing, nitride coating, metallization and firing of the metal contacts. Among these processes, the metallization plays a crucial role in the energy conversion performance of the cell. The quality of the metal layers used on the back and the front surface of the cell and the quality of the electrical contact they form with the underlying substrate have a detrimental effect on the amount of the power generated by the cell. All aspects of the metal layer, such as electrical resistivity, contact resistance, thickness, height and width of the finger layers need to be optimized very carefully for a successful solar cell operation. In this thesis, metallization steps within the crystalline silicon solar cell production were studied in the laboratories of Center for Solar Energy Research and Application (GÜNAM). Screen Printing method, which is the most common metallization technique in the industry, was used for the metal layer formation. With the exception of the initial experiments, 6‖ wafers, which are the industry standard today, were used throughout this work. v Typically, screen printing method includes 3 different printing steps on both rear and front surfaces with operating parameters such as squeegee pressure, squeegee speed and snap off. In this study, we have concurrently studied multiple parameters that would affect the metal functionality like aspect ratio, uniformity, thickness, resistance and shadow losses. We also studied the back surface field formation by the aluminum diffusion on the back side of the cell. Subsequent to the printing optimization, drying and firing steps of the metallization were also studied. The improvement in the metallization alone has led to an increase in the efficiency of the cell and a photon conversion efficiency of 15.26 % was obtained. Quality control studies conducted with Ferro GmbH proved the accuracy and the efficiency of the screen printing process carried out at GUNAM. With the improvements in other processes like laser edge isolation, we have reached to an efficiency value of 17 % at GÜNAM Laboratories Recent advances in PV technologies are based on new cell designs such as back contact solar cells, buried contact solar cells, metallization through solar cells and selective emitter solar cells. All these new technologies employ new metallization schemes that enhance the cell performance. These new cell designs and other new innovative approaches will be the subject of our future studies.


Hydrothermal synthesis of TiO₂ nanostructures for photocatalitic and photovoltaic applications
Erdoğan, Nursev; Öztürk, Abdullah; Park, Jongee; Department of Metallurgical and Materials Engineering (2017)
Titanium dioxide (TiO2) nanostructures with different crystal structures and various morphologies were synthesized by hydrothermal process to utilize them in photocatalytic and photovoltaic applications. The investigations were conducted in three different sets of systematic experimental studies. The first set of experiments was based on the synthesis of TiO2 nanostructures in the presence of strong sodium hydroxide (NaOH) catalyzer. Temperature and molarity of NaOH were kept constant while hydrothermal rea...
Development of hole transport transparent conductive electrodes for n-type crystalline silicon solar cells
Akdemir, Ozan; Bek, Alpan; İmer, Muhsine Bilge; Department of Micro and Nanotechnology (2018)
Conventional transparent conductive electrodes (TCEs) used in crystal silicon (c-Si) solar cells are commonly made of indium tin oxide (ITO) which provides low sheet resistance and high transparency. However, due to indium scarcity, ITO layers increase the fabrication cost; thus, alternative TCEs, such as fluorine-doped tin oxide (FTO), zinc oxide (ZnO), metal nanowires and Oxide/Metal/Oxide (OMO) multilayers, are being investigated. Conventional solar cells also make use of doped layers, to create the junc...
Polymer light emitting diodes and organic solar cells towards ito free devices and high efficiency devices using electrochemically synthesized polymers /
Hızalan Özsoy, Gönül; Toppare, Levent Kamil; Department of Chemistry (2017)
In this study, polymer based solar cells and polymer based light emitting diodes were constructed. In the third and fourth chapters of this study, effect of terminal units and effect of molecular weight on electroluminescence and photovoltaic properties were investigated. Triphenyl end capped polymer P1 based PLED shows luminance value of 10411cd/m2 at 8.5V whereas benzene end capped polymer P2 based PLED has the peak luminance value of 14583cd/m2 at 8V. P2 based photovoltaic devices exhibited superior perf...
Optimization of Silicon Nitride (SiN X ) Anti-reflective coating (arc) and passivation layers using industrial plasma enhanced chemical vapor deposition (pecvd) for perc type solar cells
Kökbudak, Gamze; Orhan, Efe; Es, Fırat; Semiz, Emel; Turan, Raşit (2018-07-06)
This study focuses on optimization of silicon nitride (SiN X ) Anti Reflective Coating (ARC) layer deposited on the front side of industrial Passivated Emitter and Rear Cell (PERC) type solar cells in an industrial tube type plasma enhanced chemical vapor deposition (PECVD) tool. Reflection and thickness optimization studies of ARC layer was carried out through a matrix composed of critical plasma parameters. Characterization of the layers were conducted via ellipsometry and reflectivity measurements for un...
Optimization of Pyrolysis and Liquid Silicon Infiltration Parameters for the Processing of C C SiC Composites
Tulbez, Simge; Esen, Ziya; Dericioğlu, Arcan Fehmi (2016-11-25)
The aim of the current study is to investigate the production and characterization of Carbon Fiber Reinforced Silicon Carbide (C/C-SiC) Matrix Composites. Liquid silicon infiltration (LSI) method was utilized to produce the C/C-SiC composites. Processing of these composites via LSI process contains there main steps: Carbon Fiber Reinforced Polymer (CFRP) composite production, pyrolysis and liquid silicon infiltration. Each production step has an important effect on the efficiency of the LSI process, therefo...
Citation Formats
O. Demircioğlu, “Optimization of metalization in crystalline silicon solar cells,” M.S. - Master of Science, Middle East Technical University, 2012.