Perovskitoid with a Zwitterion Cysteamine Transformation to Ruddlesden-Popper Phase

Perovskitoid with a Zwitterion Cysteamine Linker and Crystal–Crystal Transformation to Ruddlesden-Popper Phase

This work reports the synthesis of a new low-D hybrid perovskitoid using zwitterion cysteamine (2aminoethanethiol) linker and its remarkable molecular diffusion-controlled crystal-to-crystal transformation to the Ruddlesden-Popper phase. The research group demonstrates the applicability of the new perovskitoid yellow phase as an excellent active layer in a self-powered photodetector and for selective detection of Ni²⁺ via On-Off-On-On photoluminescence (PL).

Overview-

• The research group demonstrate synthesis of a new low-D hybrid perovskitoid (a perovskite-like hybrid halide structure, yellow crystals, P21/n space group) using zwitterion cysteamine (2aminoethanethiol) linker, and its remarkable molecular diffusion-controlled crystal-to-crystal transformation to Ruddlesden-Popper phase (Red crystals, Pnma space group).
• Stable intermediate perovskitoid distinctly differs from all previous reports by way of a unique staggered arrangement of holes in the puckered 2D configuration with a face-sharing connection between the corrugated-1D double chains.
• The PL intensity for the yellow phase is 5 orders higher as compared to the red phase and the corresponding average lifetime is also fairly long (143 ns).
• First principles DFT calculations conform very well with the experimental band gap data.
• The research group demonstrate applicability of the new perovskitoid yellow phase as an excellent active layer in a self-powered photodetector and for selective detection of Ni²⁺ via On-Off-On photoluminescence (PL) based on its composite with few-layer black phosphorous.

Study design-

• The reaction of PbI₂ (1 equivalent) with cysteamine (3 equivalent) in HI solution was carried out at 250°C resulting in the growth of yellow crystals of (HSC₂ H₄NH₃)₇Pb₄I₁₅.
• An interesting transformation of the yellow crystals into the red crystals was observed in the solution at room temperature after 2-3 hours.
• This suggests that the cysteammonium iodide diffusing slowly from the solution into the (intermediate) yellow crystal renders the crystal-to-crystal rearrangement.
• The experimental and simulated X-ray diffraction patterns of 1 and 2 were matched to check the purity of the dried compounds.
• The PXRD patterns matched well with the simulated pattern with no detectable impurity peaks.
• PL of perovskitoid quantum dots exhibits a multi-peak structure (with peaks roughly equal on the energy scale). It will be addressed and pursued in future work.

Image Source- onlinelibrary.wiley.com

Key Findings-

• A zwitterion cysteamine linker is used for the first time to synthesize a unique organic-inorganic single-crystal perovskitoid structure.
• It is further shown that this yellow phase gradually (kinetically) transforms into a red-colored compound if left in the reaction medium.

Generalized Results-

• This is the first time an organic-inorganic single-crystal perovskitoid structure has been synthesized using a zwitterion cysteamine linker.
• It is further shown that this yellow phase gradually (kinetically) transforms into a red-colored compound if left in the reaction medium.
• The reaction of PbI 2 (1 equivalent) with cysteamine (3 equivalent) in HI solution was carried out at 250°C resulting in the growth of yellow crystals of (HSC₂ H₄NH₃)₇Pb₄I₁₅.

Future Work Perspectives-

• PL of perovskitoid quantum dots exhibits a multi-peak structure (with peaks roughly equal on the energy scale).

An Organic–Inorganic Perovskitoid with Zwitterion Cysteamine Linker and its Crystal–Crystal Transformation to Ruddlesden-Popper Phase

Research Paper Detail in PDF

About the author

About the Author

More Detail

Prof. Satishchandra B. Ogale

• Research Institute for Sustainable Energy (RISE), India

Prof. Satishchandra B. Ogale is Emeritus Professor, IISER Pune, and Director, Research Institute for Sustainable Energy (RISE), Kolkata,
Department of Physics. He received his Ph.D. degree in 1980 from the Poona University, India. His major interests include Nanotechnology and Advanced Functional Materials, Solar energy and optoelectronics, Spintronics, Thin Films, and Heterointerfaces, Self-assembly, and pattern formation.  

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