In recent decades, there has been increasing concern about the impact of climate change on the earth. Various countries are actively developing sustainable energy technologies, of which solar cell is one of the new energy sources with the most attention. This thesis is based on poly−Si(O_x) cells consisting of SiO_x/poly−Si(O_x) passivating contact. Various methods have been investigated to mitigate the TCO (IWO) deposition induced passivation degradation and to optimize the screen printing process.

First, approaches to reduce the passivation degradation due to IWO deposition were explored. The power density and working pressure in IWO deposition were optimized. With utilizing 1.23 W/cm² power density and 5×10⁻³ mbar working pressure, the 𝑖𝑉_𝑂𝐶 degradation was reduced to 4.7 mV for 𝑛⁺ sample (NAOS-SiO_x) and to 7.9 mV for 𝑝⁺ sample after deposition of 75 nm IWO. Besides, hydrogenated amorphous silicon and AZO were used as buffer layers for the 𝑝⁺ SiO_x/poly−Si(O_x) samples, finding that they were effective in reducing sputtering damage. Then, the optimal post-annealing condition was investigated, which turned out to be vacuum annealing at 400 ^◦𝐶 for 30 min, recovering the 49 mV and 60 mV 𝑖𝑉_𝑂𝐶 for 𝑛⁺ sample (thermal-SiO_x) and 𝑝⁺ sample, respectively. Based on the above experiments, the first cells were prepared with a maximum efficiency of 17.4%.

Second, the existing screen printing process in the lab was optimized. The 0.37% organic solvent was added into the silver paste, reducing the viscosity of paste. The snap-off distance was changed to 0.02 mm in order to improve the continuity of printed grids. Moreover, the squeegee speed was optimized to 30 mm/s, limiting the spreading of silver paste to 57.3 𝜇m, much narrower than the initial spreading distance of 155.3 𝜇m.

Finally, a batch of poly−Si(O_x) cells were prepared by applying the above various optimized conditions. The cell with optimized IWO and optimized screen printing process performed best with an champion efficiency of 18.9%.