Nanostructure enhanced photovoltaic devices

Aurang, Pantea
There are mainly three generations of solar cells that have been categorized by considering their efficiency and manufacturing cost. Although lots of investigations and research is going on in this field, but the first generation solar cells are most commercially available solar cells. First generation solar cells consist of single and multi-crystalline silicon (Si), which has been doped typically by phosphorus and boron in a p-n junction configuration. Si is non-toxic, relatively low cost and naturally abundant semiconducting material, which make it quite beneficial to be employed in microelectronics and photovoltaic industry. In general, Si solar cells contain, a Si active layer sandwiched with antireflection layer and metallic contacts. Solar cells fabricated from solar grade Si shows high efficiency; however, the impurity level should be kept in minimum. Moreover, cell production process consists of high energy consuming steps such as co-firing of the contacts in metallization step (900°C) and antireflective coating deposition via plasma enhanced chemical vapor deposition (PECVD) which necessitate high temperatures (400°C) and vacuum. Improving performance of conventional Si solar cells and decreasing costs by consuming less expensive materials is an important challenge that should be overcome. Employing nanostructured materials instead of bulk or thin film components can be a promising route, which recently inspired many scientists. Nanowires that are synthesized via low-cost and solution-based methods can be utilized in any of the cell components to provide distinct advantages, which is the main theme of this thesis. In this regard, independently, vertically aligned zinc oxide nanowires are utilized as antireflection coatings, random silver nanowire networks are used as top electrodes and vertically aligned Si nanowires on ultrathin Si wafers are used as the active layer in crystal Si solar cells.


Selective emitter formation via single step doping through laser patterned mask oxide layer for monocrystalline silicon solar cells
Çiftpınar, Emine Hande; Turan, Raşit; Department of Physics (2014)
Selective emitter is one of the new approaches for higher efficiency solar cells. Although selective emitter cells could be processed by several different methods such as; etch back process, laser doping, ion implantation, doping paste, a different method based on diffusion through a laser patterned oxide layer was studied in this thesis. Utilization of pattern oxide layer as a diffusion barrier enables to obtain selective emitter profile via single step doping which reduces overall production cost and time...
Contact resistivity analysis of different passivation layers via transmission line method measurements
Kökbudak, Gamze; Turan, Raşit; Yerci, Selçuk; Department of Micro and Nanotechnology (2017)
Crystalline silicon (c-Si) homojunction solar cells constitute over 90% of the current photovoltaic market. Although the standard solar cells are cost effective and easy to process, their efficiency potential is unfortunately limited. Currently, more innovative cell concepts appeared with their high efficiency potential coupled with low costs. Since the recombination at surfaces and under metal contacts is one of the major obstacles against high conversion efficiencies, surface passivation has primary impor...
Surface texturing study with aluminum induced texturing method on soda-lime glass substrates for thin film solar cells
Ünal, Mustafa; Turan, Raşit; Ünalan, Hüsnü Emrah; Department of Micro and Nanotechnology (2017)
It is essential to employ an effective light trapping scheme to decrease the cost of produced solar electricity further in thin film solar cell technologies. There are several methods that can be used for light trapping and aluminum induced texturing (AIT) is one of them. The aim of this thesis study is to obtain highly effective light trapping interface via texturing of glass surface by AIT process. The resultant texture is affected by several parameters such as Al thickness, annealing time and temperature...
Analysis of boron doped hydrogenated amorphous silicon carbide thin film for silicon heterojunction solar cells
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...
A numerical analysis of interdigitated back contacted silicon solar cells
Acar, Beran; Yerci, Selçuk; Turan, Raşit; Department of Electrical and Electronics Engineering (2018)
The state-of-the-art solar cells manufactured using crystalline silicon (c-Si) are highly cost-effective, competing with fossil fuel-based energy sources. However, relatively more complex cell structures (i.e. interdigitated back contact, IBC) need to be developed to further increase the efficiency/cost ratio. In this thesis, the effects of structural parameters such as cell dimensions, metal contact geometry and contact resistances on the efficiency of IBC and bifacial IBC silicon solar cells were studied ...
Citation Formats
P. Aurang, “Nanostructure enhanced photovoltaic devices,” Ph.D. - Doctoral Program, Middle East Technical University, 2015.