Luminescent Zero-Dimensional Hybrid Lead Thiohalide Nanostructures for High Quantum Yield and Broadband Excitation

Abstract

Luminescent trans-[Pb(DMTU-S) 4 Cl 2 ] (DMTU: N,N′-dimethylthiourea) was designed and prepared via either mechanochemical or solvothermal methods, and the structures of DMTU and trans-[Pb(DMTU-S) 4 Cl 2 ] have been resolved using Xray single-crystal diffraction. Upon excitation over broadband covering the range from 450 to 250 nm, trans-[Pb(DMTU-S) 4 Cl 2 ] shows yellow-green emission peaking at 549 nm with a spectral width of 110 nm, which is assigned to the triplet−singlet transition of Pb 2+ ions within distorted heterogeneous S 4 Cl 2 octahedra. The broadband excitation comprised singlet−singlet transitions of Pb 2+ ions and energy transfer from orbitals involving those of organic ligands. Simultaneous analysis of the luminescent bandwidth and Stokes shift gives for Pb 2+ ions in S 4 Cl 2 octahedra the value of the Huang−Rhys parameter S = 4.25 and the energy of phonon involved in the formation of the luminescence spectrum of the order of 90 meV. Quantum yield as high as 91% is detected for excitation at 365 nm. This high quantum yield indicates the absence of noticeable concentration quenching at an average distance of 9.4 Å between the Pb 2+ ions within the structure of trans-[Pb(DMTU) 4 Cl 2 ]. The weak spin−orbit intersystem crossing is deduced from a high photoluminescence quantum yield (PLQY) value. Time dependent-density functional theory (TD-DFT) calculations of the nanocluster indicate the red shift of absorption bands in Pb(DMTU) 4 Cl 2 with respect to parent DMTU. The high-performance photoluminescence and stability demonstrated promising applications in photonics.

Machine Learning Analysis and Discovery of Zero-Dimensional ns2 Metal Halides toward Enhanced Photoluminescence Quantum Yield

“…In these studies, a series of materials with differing concentration quenching are synthesized and completely characterized to reach the conclusion formulated above. However, concerning all 0D hybrid metal halides with ns 2 metal ions, including Pb 2+ , Sn 2+ , Sb 3+ , and Bi 3+ , the emission is mainly originated from the typical self-trapped excitons (STEs), which is closely related to metal halide units in their structures. ,,− Influence of concentration quenching was mentioned only for Pb 2+ in 0D trans -[Pb­(DMTU-S) 4 Cl 2 ] that belongs to a different coordination class of compounds than those which will be studied in the present paper; Pb···Pb distance 9.4 Å was established to prevent from concentration quenching in ref . Thus, the PLQY is mainly affected by the environment of central metal ions, such as the distance of metal ion, local symmetry, ability to form hydrogen bonds to the organic cations, and so on.…”

Yellow-Orange Emission in Sb3+-Doped Hexakis(thiocarbamidium) Hexabromoindium(III) Tribromide

“…For pristine (TUH) 6 [InBr 6 ]Br 3 (1), the absorption spectrum shown in Figures 2a and S5 features a low-intensity band in the range 350−420 nm with a peak at 380 nm (3.26 eV) and an intense broad band with several sub-bands in the range 200−330 nm with peaks at 300 (4.13) and 213 nm (5.82 eV). The strong absorption within 270−300 nm can be ascribed to the spinallowed transition out of charge transfer In−Br band, 32 and it is close to the edge of the band (213 nm) 13 of the thiourea cation (Figure S5). The absorption band at 380 nm may be the result of a spin-and parity-forbidden exciton transition in an isolated [InBr 6 ] 3− octahedron.…”

“…3,4 Thiourea and its derivatives are convenient and widely used nucleophiles for studying ligand substitution reactions in coordination chemistry due to their good solubility, neutral character, and high nucleophilicity and ability to form strong hydrogen bonds. 5,6 Among HMHs, only a few compounds containing protonated thiourea (CH 5 N 2 S + ) have been structurally characterized, for example, ( 12 As in the case of N,N′-dialkylthioureas, 13,14 thiourea compounds can have unique photophysical properties and find practical applications.…”

“…Protonated primary, secondary, and tertiary amines as well as cations of quaternary ammonium and phosphonium bases are widely used as organic components of HMHs. , Much less studied are compounds containing S-protonated organic substances, for example, thiourea, the ability of which to form a singly charged S-protonated cation in strongly acidic solutions is well-known. , Thiourea and its derivatives are convenient and widely used nucleophiles for studying ligand substitution reactions in coordination chemistry due to their good solubility, neutral character, and high nucleophilicity and ability to form strong hydrogen bonds. , Among HMHs, only a few compounds containing protonated thiourea (CH 5 N 2 S + ) have been structurally characterized, for example, (CH 5 N 2 S) 2 (CH 5 N 2 ) 2 [PbI 4 ], (CH 5 N 2 S) 3 (CH 6 N) 2 [Pb 2 I 9 ], (CH 5 N 2 S) 3 [PbI 5 ], (CH 5 N 2 S)­(CH 6 N) 2 [Pb 2 I 7 ], (CH 5 N 2 S) 2 [OsX 6 ] (X = Cl, Br), (CH 5 N 2 S) 6 [BiI 6 ]­I 3 , and (CH 5 N 2 S) 6 [BiBr 6 ]­Br 3 . As in the case of N , N ′-dialkylthioureas, , thiourea compounds can have unique photophysical properties and find practical applications.…”

Sn(ii)-doped one-dimensional hybrid metal halide [C5H14NO]CdCl3single crystals with broadband greenish-yellow light emission

“…In recent years, metal halide materials have attracted great attention from researchers because of their excellent photoelectric properties. [1][2][3][4][5][6] As an important branch in the field of metal halide materials, low dimensional organic-inorganic hybrid metal halides have been rapidly developed and widely used in the light emitting diode (LED) field, [7][8][9][10] X-ray fluorescence, [11][12][13][14] thermal imaging, 15 optical waveguides, 16 anti-counterfeiting, 17,18 solar cells, 19,20 etc. The diversity of organic ligands makes their structural dimension adjustable, thus further categorizing low dimensional materials into layered two-dimensional (2D) structures, 1D wire and tubular structures, and zero-dimensional (0D) molecular structures.…”