The project report aims to identify the main weakness in the most common current commercial solar cells and then find ways of overcoming these weaknesses to improve the efficiencies of solar cells.
Identifying and understanding the performance limitations for standard commercial solar cells followed by the identification and implementation of solutions to these limitations.
A detailed analysis of existing commercial solar cells based on screen-printing enabled the performance limitations of this technology to be identified. The majority have aluminium alloyed rear contacts covering the entire rear surface that now primarily limit achievable efficiencies. Such contacts provide poor rear surface passivation and poor internal reflection of light trapped within the silicon. The next greatest loss mechanism arises through the poor quality of the silicon wafers that are used commercially to keep costs low. The third largest loss mechanism results from the nature of screen-printed metal contacts on the light receiving surface where lines are wider than optimal due to the screen-printing process and the silicon surface needs to be heavily doped with phosphorus to allow good electrical contact to be formed between the metal and the silicon.
Through the development and implementation of solutions to these limitations, new world record efficiencies were achieved as a result of these technological advances. Several patents were also secured due to the innovativeness of the developments.