Bhawna Rawat

Title : Utilizing the undesirable oxidation of Lead-free perovskite for photocatalytic C(sp3)?H activation: Unraveling the serendipity

Abstract:

Hybrid halide perovskites (HHPs), whose every branch generates intrusiveness, have been utilized in solar cells from a wider perspective. However, the inclusiveness of employing HHP as a photocatalyst is in its initial stage. This study mainly focuses on the unexpected utilization of so far undesirable material vacancy-ordered MA₂SnBr₆ quantum dots synthesized from MASnBr₃ nanosheets. Here, the quantum confinement grounded a large blue shift in UV and PL spectra with a stokes shift of 420 meV, where the band gap increment is observed as size decreases in MA₂SnBr₆. Remarkably, MA₂SnBr₆ exhibits air and moisture stability, better charge transfer, and high oxidation potential in comparison to MASnBr₃. The first principle-based atomistic computations reveal the strain relaxation in the Sn-Br framework that structurally stabilizes the MA₂SnBr₆ lattice. Furthermore, direct bandgap and strongly localized valence band edge give rise to a new potential photocatalyst MA₂SnBr₆ for efficient solar-driven C(sp³)?H activation of cyclohexane and toluene under ambient conditions. The as-synthesized MASnBr₃ and its oxidized form having different ratios of Sn²⁺ and Sn⁴⁺ were subjected to cyclohexane oxidation and it was observed that the completely oxidized form i.e. MA₂SnBr₆ gave the highest yield of cyclohexanol (70 µmol/g) and cyclohexanone (87.6 µmol/g) within 6 h. The mechanism of the photo-oxidation of cyclohexane by MA₂SnBr₆ was probed thoroughly with a plethora of techniques and found that the formation of singlet oxygen is the main active species along with photogenerated holes in the oxidation of cyclohexane into K/A oils. In unconventional precedence, the present study opens new insight for MA₂SnBr₆ as a photocatalyst for such organic transformations and the new air and moisture-stable hybrid halide perovskites in general.
Audience Take Away 

• Explain how the audience will be able to use what they learn? I will talk about Perovskites material in my talk. The audience can utilize the new perovskite material for other catalytic applications.
• How will this help the audience in their job? They can synthesize this perovskite material at room temperature.
• Is this research that other faculty could use to expand their research or teaching? Yes, other faculty can teach how sometimes unwanted things could be a blessing in disguise.
• Does this provide a practical solution to a problem that could simplify or make a designer’s job more efficient? Yes, the stability, toxicity, and reusability issues are targeted in my talk and the solution is provided for these challenges.
• Will it improve the accuracy of a design, or provide new information to assist in a design problem? Yes, the researcher can utilize this perovskite in sensing or energy-harvesting applications to design a new problem.
• List all other benefits. Overall, my talk will give the knowledge of easy perovskite synthesis for challenging C-H activation reactions under green conditions.

Biography:

Bhawna Rawat completed her M.Sc. degree from the University of Delhi, India in 2019. She then joined Prof. Kamalakannan Kailasam's group at the Institute of Nano Science and Technology, Mohali, India as PhD scholar. She is an enthusiastic researcher. Currently, I have published 5 research articles with a total of 25 citations. Recently, I won the best poster prize at the National conference ETFC 2024.