A multifunctional photovoltaic-battery (PVB) which represents a new-concept integrated PVB device as a novel power source for photoelectron conversion and energy storage within one single device.
The innovation enables a small-sized, lightweight and high-efficiency photovoltaic battery (PVB) with low environmental impact and low cost. It is an integrated harvest-and-store energy device that acts as a photovoltaic under light and a battery under dark conditions. It could be applied to several solar energy solutions and would allow for more compact portable devices.
The invention tailors and fine-tunes the properties of FeS2 nanocrystals to overcome the existing problems with iron pyrite. By passivating FeS2 with atomic ionic ligands, he was able to both enhance electronic coupling and address degradation issues.
After ligand passivation, FeS2 nanocrystal PVB devices exhibit 4.07% power conversion efficiency under AM 1.5 illumination, and 57.8 mAhg-1 specific capacity under dark. The iodide passivated FeS2 PVB device has a 22x longer carrier lifetime in comparison with the EDT-treated devices. The entire solution based process can occur at room temperature, making it amenable to low-cost, roll-by-roll production on flexible substrates.
This novel type of PVB device is made from low-cost, non-toxic and earth abundant iron pyrite (FeS2) nanocrystals, otherwise known as "fool's gold". Iron is the fourth most abundant metallic element in the earth's crust and the cheapest to extract. In addition to its abundance, FeS2 has a remarkably high absorption coefficient level and ideal broad spectral light harvesting, making it a unique opportunity to incorporate a very thin absorber layer in solar cells to capture most of the incident solar radiation.
The low photovoltage, sulfur deficiencies and poor structure uniformity of iron pyrite have severely limited its use in photovoltaic applications, despite its other superior features. Therefore, commercially viable iron pyrite PVB devices have not materialized in the marketplace. This discovery makes iron pyrite PVB devices possible.
This innovation is ideal for any application that requires a lightweight, low-cost, portable green-energy solution.