The role of halide substitution in a lead-free 2D hybrid perovskite is investigated on the BZA2SnX4 (BZA = benzylammonium; X = Cl, Br and I) system, by reporting the synthesis and the structural analysis by means of single-crystal X-ray diffraction data of the two novel compositions BZA2SnBr4 and BZA2SnCl4. In addition, the mixed composition BZA2Sn(BrxI1-x)4 (0 ≤ x ≤ 1) has been prepared by mechanochemical synthesis confirming the existence of a wide solid solubility between the two end-members. The absorption and emission spectra revealed a wide tuning of the band-gap by changing the halide, covering more than 300 nm in the visible range. Combined experimental and DFT calculations provide a complete picture of the electronic and structural properties of the BZA2SnX4 system, revealing a strong influence of the halide on the orientation for the benzylammonium cation, on the hydrogen bonding system within the perovskite network, and on the distortion of the octahedra.
Exploring the role of halide mixing in lead-free BZA2SnX4 two dimensional hybrid perovskites
Listorti A.;
2020-01-01
Abstract
The role of halide substitution in a lead-free 2D hybrid perovskite is investigated on the BZA2SnX4 (BZA = benzylammonium; X = Cl, Br and I) system, by reporting the synthesis and the structural analysis by means of single-crystal X-ray diffraction data of the two novel compositions BZA2SnBr4 and BZA2SnCl4. In addition, the mixed composition BZA2Sn(BrxI1-x)4 (0 ≤ x ≤ 1) has been prepared by mechanochemical synthesis confirming the existence of a wide solid solubility between the two end-members. The absorption and emission spectra revealed a wide tuning of the band-gap by changing the halide, covering more than 300 nm in the visible range. Combined experimental and DFT calculations provide a complete picture of the electronic and structural properties of the BZA2SnX4 system, revealing a strong influence of the halide on the orientation for the benzylammonium cation, on the hydrogen bonding system within the perovskite network, and on the distortion of the octahedra.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
