A new study offers a roadmap for the design of high-performance photocatalysts that can bring benefits ranging from sustainable energy production to environmental remediation.
2D materials have a high absorption coefficient, implying that they can efficiently absorb light and generate electron-hole pairs. This makes them promising candidates for photocatalytic applications. They also have tunable bandgap, reduced path length that charge carriers need to travel, large surface area and can be easily integrated into various device architectures allowing flexibility and scalability.
However, they possess strongly bound excitons (bound state of an electron and an electron hole) and are thus ineffective in driving catalytic reactions that require free charge carriers.
Scientists from Institute of Nano Science and Technology (INST), Mohali, an autonomous institute of Department of Science and Technology, theoretically studying the ground- and excited-state dynamics of bound electrons-hole pairs (excitons) in a heterostructure of a 2D material called metal-telluro-halide demonstrated that engineering of 2D materials that have high electrical resistivity (dielectric materials) is an efficient strategy to regulate their exciton binding energy (EBE) and could make them efficient catalysts.
In a paper published in Journal of Physical Chemistry C they elucidated how the application of a magnetic field accelerates charge separation of such materials by exerting opposing forces on photogenerated electrons and holes, while also enhancing EBE through an exciton diamagnetic shift, which could potentially hinder charge separation.
The highly delocalized exciton cloud extending over a few hundred unitcells reduces the EBE to kBT (25 meV—mili electron volts), promoting spontaneous exciton dissociation into free carriers.
Using PARAM-Smriti supercomputing facility at NABI supported by CDAC, Pune under the National Supercomputing Mission, Government of India, Prof. Abir De Sarkar and his PhD Scholars Mr. Amal Kishore & Ms Harshita Seksaria showed that the GaTeCl/InTeBr vdW heterostructure efficiently splits water into hydrogen, providing a clean energy source. The same method could also be used to produce solar fuels like methanol. Additionally, its photocatalytic properties help degrade pollutants, contributing to cleaner air and water.
Publication link: https://doi.org/10.1021/acs.jpcc.4c02483
Prof. Abir De Sarkar & his PhD Scholars: Mr. Amal Kishore & Ms Harshita Seksaria
High Performance Compute (HPC) cluster where scientific computations have been performed.
