Metal Halide Perovskites and Quaternary Chalcogenides in Catalysis and Photovoltaics

Chaudhary, Sonu Pratap (2024) Metal Halide Perovskites and Quaternary Chalcogenides in Catalysis and Photovoltaics. PhD thesis, Indian Institute of Science Education and Research Kolkata India.

Text (PhD thesis of Sonu Pratap Chaudhary (17RS043)) 17RS043.pdf - Submitted Version Restricted to Repository staff only Download (12MB)

Abstract

The significant progress in the development of metal halide perovskites (MHPs) have captivated the interest of researchers for the real-time applications in optoelectronics, photovoltaics and photocatalysis. Based on the merits of having exceptional light absorption coefficient, long carrier diffusion length, defects tolerance, low exciton binding energy, and high carrier mobility, MHPs now have immense prospects for their future applications. Both lead-based and lead-free MHPs have been prominent in this entire portfolio. Lead-free MHPs having low toxicity and higher ambient stability help to investigate the various fields of photocatalysis. However, lead-based MHPs strive for significant attraction in the field of photovoltaics like solar cells, and photodetectors due to their ability to tune the lower excitonic band gaps. Also, quaternary chalcogenides are earth-abundant, environmentally benign semiconductors used in the field of photovoltaics. In this doctorate dissertation, I have developed the optically active materials including the MHPs and quaternary chalcogenides to uncover their practical applications in the broad context of sustainable energy research. The dissertation is divided into four general chapters addressing some new concepts in this regard. Chapter 3 is focused on the development of lead-free, ambient stable Cs3Bi2I9 nanodiscs (NDs) via colloidal solution-based hot injection method for the photocatalytic H2 generation from diluted aqueous hydroiodic acid (HI). With 0.005 M photostable NDs, 22.5 μmol h⁻¹ H2 is photochemically obtained within 8 h in a 6.34 M HI solution and electrocatalytically H₂ evolution with a turnover frequency of 11.7 H₂ s⁻¹ at -533 mV and outstanding operational stability for more than 20 h. The rest of three chapters are based on the development of some new techniques for solar cell device fabrication using different types of materials. In Chapter 4 the successful fabrication of a pinhole-free, compact lead-based perovskite thin films by utilizing a widely recognized probe sonication technique. In this case, the generated high energetic ultrasound collapses the bubbles through a shock wave inside the gas phase which has a chemical impact on the nucleation of the perovskite phase and the inter-connectivity of the grains. The optimized 60-min sonicated Cs₀.₁₇FA₀.₈₃Pb(I₀.₈₃Br₀.₁₇7)₃ [where FA: formadinium cation] PSC has 20.20 ± 0.40% PCE with 1000 h ambient stability having >60% retention of the original PCE. Chapter 5 delve into development of the quaternary chalcogenides- Cu₂BaSnS₄ (CBTS) and Cu₂SrSnS₄ (CSTS), where CBTS nanocrystals (NCs) and gold (Au) NCs are incorporated into core-shell heterojunction and Au/CBTS NCs are being used to fill the pinholes in the thin films of Cs₀.₁₇FA₀.₈₃Pb(I₀.₈₃Br₀.₁₇7)₃. Finally, this strategy has improved the PCE to 20.22 ± 0.55% due to the effective plasmon resonance energy transfer (PRET) effect. Lastly, In Chapter 6 the wurtzite and kesterite crystal structures of CSTS NCs are synthesized to measure the mobilty. The wurtzite phase shows higher mobility of 0.83x10⁻¹¹ cm²V⁻¹s⁻¹ than the kesterite phase having a mobility of 3.80x10⁻¹² cm²V⁻¹s⁻¹ due to lower band gap and lower trap state density.

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