Abstract
The object of this dissertation is to study the influences of temperature stress, damp heat stress and metal grid density on the energy conversion efficiency of InGaP/InGaAs/Ge multi-junction concentration solar cells. In the reliability studies, step stress accelerated degradation tests were employed to investigate the degradation of cell. In order to accelerate the observation of degradation, solar cell were not encapsulated with protective silicone layer. In the temperature stress studies, the dark and light current-voltage measurements indicated that recombination current increased, open circuit voltage decreased and energy conversion efficiency decreased. These results were caused by defects generated in the peripheral region of solar cells. In the damp heat stress studies, experimental results indicated that cracks generated at Ge substrate in the edge region of solar cell, which induced leakage path and failure of solar cell. Under light concentration condition of solar cell, more metallic electrodes can rapidly collect current and thus generate more current; however more denser electrode will also decrease the light collection area of cell. This dissertation employs a theoretical model to analyze the influence of the grid density of linear metallic grid on the electro-optical characteristics of concentration solar cells. These results were compared with outdoor experimentally measured data in order to provide the basic references for optimal designation of cell. It is found that the total power loss was dominated by grid shadowing effect at lower concentration levels, while there existed an optimal condition for compromise between grid shadowing effect and resistance of metal lines at higher concentration levels.