Optimization of novel passivation and carrier selective layers on crystalline silicon solar cell technologies

Kökbudak Baldan, Gamze
Photovoltaics offer a promising response to global energy needs in the pursuit of sustainability. As solar technology advances, researchers seek to enhance the efficiency of solar cells while simultaneously mitigating their costs. A notable innovation is the integration of novel passivation and carrier-selective layers, which has received a lot of attention and has the potential to change the field entirely. In this thesis, the optimization of passivation layers commonly used in standard passivated emitter and rear contact (PERC) structures, such as silicon nitride (SiNx), silicon oxynitride (SiOxNy), and aluminum oxide (Al2O3), has been investigated. Following the successful demonstration of the performance of these layers in p-type baseline PERC solar cells, the passivation layers were subsequently utilized in n type PERC-like structures. The fabricated n-type carrier selective metal-compound full area rear contact and partial rear contact solar cell employs the optimized electron-selective magnesium oxide (MgOx) thin film deposited using the ALD (Atomic Layer Deposition) method. Moreover, the ion implantation technique is utilized to form the emitter, which allows for single-side doping by further simplifying the process flow and creating a controllable doping profile. Such an option will pave the way for silver-free (Ag-free) solar cell manufacturing, which is highly desirable for industrial applications. It has been demonstrated as a proof of concept that MgOx can serve as a highly effective electron-selective passivating contact for n-type crystalline silicon (c-Si) solar cells. The optimized and simple manufacturing methods resulted in a remarkable solar cell efficiency of 17.17% from the 43.50 cm2 area of PERC-like carrier selective contact solar cells. To the best of our knowledge, the size of the solar cells with a MgOx layer produced in this thesis study is larger than the size of similar solar cells that have been published in the literature, which shows the potential of the ALD deposited MgOx to be applied to industrial-size Si solar cells. These findings suggest a promising potential for producing high-efficiency, cost-effective, dopant -free heterojunction solar cells.
Citation Formats
G. Kökbudak Baldan, “Optimization of novel passivation and carrier selective layers on crystalline silicon solar cell technologies,” Ph.D. - Doctoral Program, Middle East Technical University, 2023.