Efficient Narrow-Band Green Light-Emitting Hybrid Halides for Wide Color Gamut Display

Abstract

Phosphors with narrow-band emission are in great demand for liquid crystal display backlighting applications. In this work, four zero-dimensional Mn 2+ -based organic−inorganic metal halides (OIMHs), (C 13 H 26 N) 3 MnBr 4 •Br, (C 13 H 26 N) 2 MnCl 4 , and (C 7 H 18 N) 2 MnX 4 (X = Cl, Br), were synthesized, and their crystal structures were solved. Under blue-light excitation, all of the materials exhibited bright narrow-band green luminescence centered at 515−525 nm with high photoluminescence quantum yields (PLQYs). Significantly, (C 13 H 26 N) 3 MnBr 4 •Br and (C 13 H 26 N) 2 MnCl 4 exhibited small full width at half-maximum (FWHM) values of 43 and 48 nm with PLQYs of 77.8 and 79.3% at room temperature, respectively. Compared with the reported luminescent OIMHs, ultrahigh thermal quenching temperatures were observed, and at 420 K, emission intensities of (C 13 H 26 N) 3 MnBr 4 •Br and (C 13 H 26 N) 2 MnCl 4 , remained 82.7 and 64.2% of those at room temperature, respectively. The rigid environment provided by the C 13 H 26 N + cation has a strong confinement effect on the [MnX 4 ] 2− tetrahedra, leading to a narrower FWHM and higher thermal quenching temperature. Finally, (C 13 H 26 N) 3 MnBr 4 •Br was combined with commercial phosphors to fabricate light-emitting diodes (LEDs) with a wide color gamut of up to 113% NTSC (National Television System Committee). This work provides a reference for designing the OIMHs for liquid crystal display LEDs by tuning the organic cations.

(C5N2H14)GeBr4: A 2D Organic Germanium Bromide Perovskite with Strong Orange Photoluminescence Properties

“…OIMH perovskites have flexible and adjustable structures, such as the constituent component including the selection of organic molecules, metal and halogen elements, structural dimension, and electronic structures . The dispersed organic ligands and inorganic parts endow OIMH perovskites with excellent photoelectric performances, which make them good candidates in the fields of solar cells, light-emitting diodes (LEDs), nonlinear optical (NLO) crystals, , etc. Perovskite photoelectric materials have developed rapidly, with photovoltaic efficiency increasing from 4 to 25.7% in 10 years.…”

“…The first two-dimensional (2D) Ge-based perovskite, (C 4 H 9 NH 3 ) 2 GeI 4 , was synthesized by Mitzi in 1996, which exhibited a broad PL with a peak at around 690 nm . In 2015, Kanatzidis and co-workers reported a series of Ge-based perovskites with three-dimensional and one-dimensional structures, but their PL behaviors were unknown . In 2017, Han et al successfully synthesized 2D perovskite (PEA) 2 GeI 4 (PEA = C 6 H 5 C 2 H 4 NH 3 + ), which showed a wide PL with an emission peak located at 630 nm and a PLQY of 0.6% .…”

Narrowing the band of green emission in manganese hybrids by reducing the hydrogen bond strength and structural distortion

“…In order to explore the factors influencing the fwhm, the structural parameters and PL characteristics for compounds 1 and 2 are listed in Table 1, together with those of other Mn( ii ) tetrahedral bromide hybrids with similar cyclic organic cations reported in previous literature. 12,15,16,27,28,43,44 As highlighted in Fig. 3, a strong dependence is observed between the fwhm values of their green emission and the bond length distortion degree ( λ tet ) of the Mn tetrahedron, where the smaller the λ tet value is the narrower the fwhm is.…”

“…24,25 Although the 0D tetrahedral Mn(II) OIMHs exhibit similar crystal structures and luminescence behaviors, their fwhm values in the PL spectra still differ in the range from 35-65 nm. [11][12][13][14][15][26][27][28] The regulation of fwhm is crucial, considering that the narrower the fwhm, the wider the color gamut can be achieved in the fabricated LEDs. 29 Concerning the factors influencing fwhm, Kovalenko's group demonstrated that by selecting halogens (chloride, bromide or iodide), fwhm can be regulated through the altered ligand-field effects and spinorbit coupling.…”

“…26 Recently, Wang et al synthesized several 0D green-emitting Mn(II) halides and suggested that the cyclic organic cations rather than the chain-like ones in the structure facilitate a small fwhm. 28 It was reported that the distortion degree of the inorganic unit and the hydrogen bonding strength in the structure have crucial effects on PLQY, solvatochromic PL and thermochromic PL behaviors of Pb-, Bi-, Snand Sb-based systems. [30][31][32][33] However, to our knowledge, the effects of these structural and bonding factors on the fwhm in green-emitting Mn(II) hybrids have not been reported yet.…”