Broad Photoluminescence and Second-Harmonic Generation in the Noncentrosymmetric Organic–Inorganic Hybrid Halide (C₆H₅(CH₂)₄NH₃)₄MX₇·H₂O (M = Bi, In, X = Br or I)

Abstract

Recent discoveries in organic−inorganic metal halides reveal superior semiconducting and polarization properties. Herein, we report three organic–inorganic metal halides, (PBA)4BiBr7·H2O, (PBA)4BiI7·H2O, and (PBA)4InBr7·H2O [(PBA)+ = C6H5(CH2)4NH3 +], with band gaps of ∼3.52, ∼2.29, and ∼4.05 eV, respectively. They possess zero-dimensional structures containing the inorganic octahedra [MX6]3– (M = Bi, In, X = Br, I) and unbound X– ions and crystallize in the C2 space group. (PBA)4BiI7·H2O shows a second-harmonic-generation (SHG) response in the infrared region, approximately 1.3 times that of AgGaS2; (PBA)4BiBr7·H2O and (PBA)4InBr7·H2O show SHG responses in the ultraviolet region, approximately 0.4 and 0.6 times that of KH2PO4, respectively. The large SHG responses are attributed to the synergistic contribution of the octahedral distortion of [MX6]3– (M = Bi, In, X = Br, I) and the ordered arrangement of the benzene ring-containing organic cation PBA+. Upon ultraviolet and visible-light excitations at room temperature, (PBA)4BiBr7·H2O, (PBA)4BiI7·H2O, and (PBA)4InBr7·H2O exhibit broad red-light luminescence with large Stokes shifts of 290, 237, and 360 nm, respectively, due to self-trapped exciton emission. All of these properties demonstrate that this series of metal halides are potential multifunctional optoelectronic materials.

Antimony doping to enhance luminescence of tin(iv)-based hybrid metal halides

“…The isolated halogen anions were also reported in other OIMHs. 22,31 For (C 9 H 15 N 3 ) 2 SnCl 8 , the bond lengths of Sn-Cl range from 2.4136 (4) to 2.4431(4) Å, and the bond angles of Cl-Sn-Cl vary from 87.630(15)°to 92.371(15)°. For (C 9 H 15 N 3 ) 2 SnBr 8 , the bond length of Sn-Br is longer, ranging from 2.5752 (4) to 2.6078 (4) Å, and the bond angles of Br-Sn-Br range from 87.670 (14)°to 92.330( 14)°.…”

Symmetry breaking of A3M2X9-type perovskite derivatives induced by polar quaternary ammonium cations: achieving efficient nonlinear optical properties

“…The distortion degree is calculated as (Δd ¼ 1=6 P 6 i¼1 ½ðd i À d 0 Þ=d 0 2 . d i is the Bi-Cl bond length and d 0 is the mean Bi-Cl bond length) 45 of two [BiCl 6 ] 3− octahedra which are 3.6 × 10 −3 and 4.3 × 10 −3 , respectively, and are much higher than those of (TMEDA)BiI 5 (0.957 × 10 −3 ), 46 (TMEDA)SbI 5 (1.489 × 10 −3 ), 46 (PBA) 4 BiBr 7 •H 2 O (3.27 × 10 −3 ), 47 (PBA) 4 BiI 7 •H 2 O (3.20 × 10 −3 ), 47 (PBA) 4 InBr 7 •H 2 O (2.61 × 10 −3 ), 47 (R-/S-MBA)BiI 4 (1.5 × 10 −3 and 2.3 × 10 −3 ), 48 and (R-/S-MPEA) 2 CuCl 4 (3.32 × 10 −4 and 3.07 × 10 −4 ), 49 indicating that the lone pair of Bi 3+ cations in (BTA) 3 BiCl 9 is more chemically active. In addition, organic moieties arranged in order connect to the inorganic [Bi 2 X 9 ] 3− polyhedra via weak C-H⋯Cl hydrogen bonding (see Fig.…”

Antimony and bismuth cooperation to enhance the broad yellow photoluminescence of zero-dimensional hybrid halide

“…Compared with the high-efficiency emission of Sb 3+ in OIMHs, Bi 3+ has not been observed to exhibit good photoluminescence properties in recently reported research. [18][19][20][21][22] However, the effect of bismuth dopants on In-based halide perovskites (represented by Cs 2 AgInCl 6 perovskites) has been extensively studied in the field of all-inorganic perovskites. In these studies, by adjusting the optical bandgap, 23 breaking the parity forbidden transition, 24 promoting light absorption and introducing an energy transmission channel, [25][26][27] Bi 3+ has been shown to play a role in photoluminescence (PL), which is different from the luminescent center Sb 3+ .…”