Research Journey

Research Statement

• Over the past years, the demand of solar energy has increased exponentially. It is very essential source of electricity to fight with the climate change and reduce the carbon footprint.

• In India alone, solar energy has huge potential. If 1% of land mass of India is utilized for solar energy generation, approximately 800GW of energy can be generated by using current technologies. The installed solar energy has reached 53GW as of march 2022 and increasing very fast every year.

• Current Photovoltaic industry is dominated by the Silicon based solar modules, particularly mono-crystalline Silicon solar cell because of its high efficiency. The efforts have been made to enhance the efficiency to the theoretical limit. Also, the progress is made via III-V/Si tandem solar cell.

Past Research

• I have carried my research on the single junction and dual junction solar cell using Silvaco ATLAS TCAD simulation methodology in ASTM certified AM1.5G environment. My main focus was to design crystalline-Silicon based single junction and III-V compound/Silicon based dual junction solar cell.

• Efforts have been made to improve the efficiency of Silicon solar cell by modifying the electrode structure and Applying Tunnel oxide passivated Contact (TOPCon) technology. The GaInP based single junction compound solar cell is designed and performance improvement is done via the double back surface field optimization.

• I also designed type-A quantum well structure using InP materials and incorporated it in the p-i-n region of the GaInP cell. The designed QWs absorbs the sub-bandgap photon energy and contributed in the short circuit current improvement.

• The above designed two individual cells are now integrated using high bandgap buffer layers and highly doped tunnel junction. This resulted in enhancement of efficiency more than the single junction crystalline Silicon solar cell.

• The method of quantum well incorporation and TOPCon technology is applied to the integrated GaInP/Si dual junction solar cell. The Quantum well increases the short circuit current and TOPCon technology enhance the open circuit voltage. Thereby, enhances the overall performance of the dual junction solar cell.

Future Agenda

• The Si cell performance can be further improved by using Quantum dots (QDs), colloidal QDs and nanowires on the top of the Si cell.

• The top cell can be designed from other compound material, which has low bandgap as compared to the GaInP material like GaAs, GaAsP, GaSb etc. this cell can achieve efficiency higher than the GaInP cell. This low bandgap compound material cell can be electrically connected with the c-Si solar cell to further enhance the dual junction efficiency.

• The bandgap modulation using QDs and QWs can be performed at the top cell and the TOPCon technology can be provided in the bottom cell to further enhance the efficiency.

• The agenda also include the design of multi junction solar cell (more than 2 junction) with the Silicon as lowermost subcell, to enhance the efficiency to theoretical limit. Also, the compound material based multijunction solar cell with quantum well structure can be designed for higher efficiency.

• The Thin-Film solar cell can reduce the cost of the PV module, but the lower efficiency restricts the mass production. Improvment can be done by optimization and and using QW, QDs etc.