4P-028
Structure and Properties of Organic-Inorganic Layered Perovskites
based on MBr4 (M=Pb,Cu)(Graduate School of Chemical Science and Engineering, Hokkaido Univ.1, Faculty of Science,
Hokkkaido Univ.2, JST-CREST3) Giancarlo S. Lorena1, Tsuyoshi Osaki1, Yu Kudo1, Hiroyuki
Hasegawa2,3, Yukihiro Takahasi1,2,3, Jun Harada1,2,3, Tamotsu Inabe1,2,3[Introduction]
As can be seen in dielectrics and superconductors, the electronic structure ofperovskite compounds, also known as a "storehouse of function" can be easily controlled bysubstitution of its constituent elements. Among these compounds, metal-halide perovskites
are generally soluble in a variety of solvents. Therefore, they have the advantage for easy
device fabrication. Our lab, has previously revealed that the spontaneous doping is the originof high conductivity in exceptionally high conductive tin iodide organic and inorganic hybrid
perovskite compounds, and also reported the rectification effect in mixed crystals with lead
iodide due to the non-uniformity of chemical composition. Clarification of design guidelines
for physical properties of these materials is important from the viewpoint of applications
such as solar cells or field-effect transistors which are actively studied in recent years.
In this study, synthesis of organic-inorganic layered perovskites based on MBr4
(M=Pb,Cu) were done. Single crystals of these hybrids were synthesized. The effects ofchanging the organic component in the synthesis of these hybrid materials were studied.

[Experimental](R-NH3)2PbBr4 Perovskite compounds can be easily synthesized by dissolving
stoichiometric amounts of organic ammonium bromide and Lead(II) Bromide using a mixed
solvent of DMF in Chloroform then slowly cooling of the heated solution. See schematic
below:(R-NH3)2CuBr4 Perovskite compounds on the other hand, can be synthesized bysimply dissolving stoichiometric amounts of organic ammonium bromide and Copper(II)Bromide and using H2O as a solvent. Recrystallization using the same solvent allows forbetter crystal quality. See schematic below;

[Results and Discussion]
Crystal structure and Optical band gap of (R-NH3)2MBr4 (M=Pb,Cu) Perovskites

Organic - Inorganic layered Perovksites having the formula (R-NH3)2PbBr4 show
relative stability under ambient conditions. Analysis of crystal structure shows thatregardless of organic cation used, these compounds show similar Lead-Bromide bond length
as well as similar Lead-Bromide-Lead bond angle within the inorganic layer. Furthermore,these compounds show similar optical band gap value of about 3.0 eV.
Organic - inorganic layered perovskites based on (R-NH3)2CuBr4, are also relatively
stable under ambient conditions. Unlike (R-NH3)2PbBr4 layered perovskites, analysis of thecrystal structure of these compounds shows unequal Copper-Bromide bond length andCopper-Bromide-Copper bond angle within the inorganic layer which suggest the presenceof Jahn-Teller distortion in these layered perovskites. Moreover, a relatively smaller gap was
found in the optical spectra.
Due to the easy synthesis protocol, relative stability and possibility of being able totune of the properties of these compounds, these organic-inorganic layered perovskites
based on MBr4 have the potential for easy device fabrication and manipulation.