light harvesting. The increase in optimal band gap also results in a larger open-circuit voltage (VOC), which affects the efficiency as well. Silicon photovoltaics, the most common type of photovoltaic cell in the market, is only able to reach an efficiency of around 8% when harvesting ambient indoor light, compared to its 26% efficiency in sunlight. One possible alternative is to use amorphous silicon, a-Si, as it has a wider band gap of 1.6 eV compared to its crystalline counterpart, causing it to be more suitable to capture the indoor light spectra. Other promising materials and technologies for indoor photovoltaics include thin-film materials, III-V light harvesters, organic photovoltaics (OPV), dye-sensitized solar cells and perovskite solar cells. Thin-film materials, specifically CdTe, have displayed good performance under low light and diffuse conditions, with a band gap of 1.5 eV. Some single junction III-V cells have band gaps in the range of 1.8 to 1.9 eV, which have been shown to maintain good performances under indoor lighting, with an efficiency of over 20%. There has been various organic photovoltaics that have demonstrated efficiencies of over 16% from indoor lighting, despite having low efficiencies in energy harvesting under sunlight. This is due to the fact that OPVs have a large absorption coefficient, adjustable absorptions ranges, as well as small leakage currents in dim light, allowing them to convert indoor lighting more efficiently compared to inorganic PVs. Dye-sensitized solar cells have reached efficiencies of over 28% under low light illumination, through judicious design of sensitizers and electrolytes. Perovskite solar cells have been tested to display efficiencies over 25% in low light levels. While perovskite solar cells often contain lead, raising the concern of toxicity, lead-free perovskite inspired materials also show promise as indoor photovoltaics. While plenty of research is being conducted on perovskite cells, further research is needed to explore its possibilities for IPVs and developing products that can be used to power the internet of things. Solar pumps One of the most cost effective solar applications is a solar powered pump, as it is far cheaper to purchase a solar panel than it is to run power lines. They often meet a need for water beyond the reach of power lines, taking the place of a windmill or windpump. One common application is the filling of livestock watering tanks, so that grazing cattle may drink. Another is the refilling of drinking water storage tanks