Controllable Lenses for Photovoltaic Energy Generation Enhancement

Fixed-focal point solar concentrators have been used in high-power density applications. However, the inability to control the focal point often saturates the energy generation of the cells and exposes them to excessive heat. In this condition, the efficiency of solar cells drops rapidly and results in low energy production. This paper introduces a controllable focal point lens to maximize the energy generation of thin-film and thick-film solar cell. An electrowetting phenomenon is used to control the curvature and the focal point of the lens. The voltage that is applied across the lens directly controls the light intensity on solar cell areas. Therefore, it can control the energy generation and operating temperature of the cells. Experimental results prove the effectiveness of the focal point lens in energy generation enhancement in thick and thin films. Thick-film solar cells generate more power at high electrowetting voltage, whereas thin films that maximize the power at low electrowetting voltage. The P-V curves of thick films demonstrated a decrease in solar cell voltage of the maximum power point. Thin-films demonstrated an increase in cell voltage of the maximum power point at higher electrowetting voltage of low sunbeam intensities. The controllable lens increased the energy production by 78%.