Study of the light energy harvesting capacity in indoor environments

Systems involving solar energy harvesting typically need to be designed under the horizon of the energetic environmental limitations that are inserted. The objective of this work is to investigate and raise the capacity of solar energy scavening in four selected indoor environments, aiming at the applicability of energy harvesting circuits in mobile electronics or wireless sensor network, for example. For this purpose, a photovoltaic wafer cell was characterized in a controlled environment. A circuit for I-v curve extraction was developed and estimations of maximum power transfer by area were raised. The characterization results showed 14.04 % for the wafer conversion efficiency at maximum power operation point (MPP) and a respective voltage of 73 % in relation to VOC. Regarding the environments testing, location with indirect sunlight, a few hundred µWatts were captured, while in artificial illumination some tens of µW. So, using the device proposed in this paper, it was possible to quantify the energy harvesting capacity of different environments in real time.