Is CH3NH3PbI3 Polar?

Sharada, G and Mahale, Pratibha and Kore, Bhushan P and Mukherjee, Somdutta and Pavan, Mysore S and De, Chandan and Ghara, Somnath and Sundaresan, A and Pandey, Anshu and Row, Guru Tayur N and Sarma, DD (2016) Is CH3NH3PbI3 Polar? In: JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 7 (13). pp. 2412-2419.

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Abstract

In view of the continued controversy concerning the polar/nonpolar nature of the hybrid perovskite system, CH3NH3PbI3, we report the first investigation of a time resolved pump probe measurement of the second harmonic generation efficiency as well as using its more traditional form as a sensitive probe of the absence/presence of the center of inversion in the system both in its excited and ground states, respectively. Our results clearly show that SHG efficiency, if nonzero, is below the limit of detection, strongly indicative of a nonpolar or centrosymmetric structure. Our results on the same samples, based on temperature dependent single crystal X-ray diffraction and P-E loop measurements, are entirely consistent with the above conclusion of a centrosymmetric structure for this compound in all three phases, namely the high temperature cubic phase, the intermediate temperature tetragonal phase and the low temperature orthorhombic phase. It is important to note that all our experimental probes are volume averaging and performed on bulk materials, suggesting that basic material properties of CH3NH3PbI3 are consistent with a centrosymmetric, nonpolar structure.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY LETTERS
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	25 Aug 2016 05:08
Last Modified:	25 Aug 2016 05:08
URI:	http://eprints.iisc.ac.in/id/eprint/54405

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