Research Projects

The energy harvested or produced by the solar cells needs to be stored by devices such as battery to power-up the appliance. Both energy harvesting, conversion and storage require two different type of mechanism and hence different materials with these functionalities. The merger of above two functionalities in a single device would significantly improve the volumetric performance, will provide more compact energy solutions for standalone electronic devices, reduced cost of fabrication etc., however this is challenging because of material and manufacturing incompatibilities between energy harvesting and storage materials. Therefore, apart from bringing out a sustainable way for power production, these devices will open up avenues for charging the battery in the likely events of electrical input unavailability. The demonstrated perovskite photobattery, by the PI, when fully photo-charged can power a commercial 3V white light LED (operating at electrical power of ∼0.6 mW) for more than an hour. Though this performance of perovskite based photobattery is a breakthrough for the proof of concept device in the very first demonstration, which promise that there is lot of scope for the improvement for real device applications. Only few PRBs are reported so far which exploits the heterojunctions to maximize the solar energy harvesting and extraction of photogenerated charge carriers. Moreover, all the PRBs reported so far make use of the intercalation reaction mechanism for the storage of ions. In order to obtain a high performance PRBs, it is imperative to look for stable active materials where the conversion reaction mechanism can be exploited for photocharging as well as the materials should not have above mentioned technical issues. Since intercalation based host materials can accommodate less than 1 mol Li+ per mol whereas, conversion type materials can accommodate more than 1 Li+ per mol, which will result in high capacity PRBs. The proposed project will be mainly focussing on the development of photo-rechargeable Li-ion batteries by investigating conversion type antimony trisulphide (Sb₂S₃) and MoS₂ heterojunctions to achieve highly stable and efficient photobatteries. Sb₂S₃ is known for its excellent optoelectronic properties such as suitable direct band gap (1.4-1.8 eV), high absorption coefficient (10⁵ cm-1) in the visible spectrum, high electron and hole mobilities which makes crystalline Sb₂S₃ a promising photon-harvesting material for solar cells. Moreover, for energy storage applications, Sb₂S₃ can possess specific capacity as high as 946 mAh g-1 through conversion and alloying reactions. Therefore, these interesting photovoltaic and electrochemical properties makes it a suitable candidate for the Li-PRB application. Therefore, the use of proposed Sb₂S₃-TMD heterostructures as single active material in two-electrode configuration based Li-PRBs, would be useful in achieving stable and efficient operation of PRB.