Author
Antoine Blaise Kama
Other affiliations: University of Nantes
Bio: Antoine Blaise Kama is an academic researcher from Cheikh Anta Diop University. The author has contributed to research in topics: Hydrogen bond & Salt (chemistry). The author has an hindex of 2, co-authored 8 publications receiving 50 citations. Previous affiliations of Antoine Blaise Kama include University of Nantes.
Papers
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TL;DR: It is demonstrated that Mn doping as low as 0.027% in the hybrid post-perovskite type (TDMP)PbBr4 enables to achieve a bright pure white emission replicating the spectrum of the Sun'rays.
Abstract: Near-UV-pumped white-light-emitting diodes with ultra-high color rendering and decreased blue-light emission is highly desirable. However, discovering a single-phase white light emitter with such characteristics remains challenging. Herein, we demonstrate that Mn doping as low as 0.027 % in the hybrid post-perovskite type (TDMP)PbBr4 (TDMP=trans-2,5-dimethylpiperaziniium) enables to achieve a bright pure white emission replicating the spectrum of the sun's rays. Thus, a white phosphor exhibiting an emission with CIE coordinates (0.330, 0.365), a high photoluminescence quantum yield of 60 % (new record for white light emission of hybrid lead halides), and an ultra-high color rendering index (CRI=96, R9=91.8), corresponding to the record value for a single phase emitter was obtained. The investigation of the photoluminescence properties revealed how free excitons, self-trapped excitons, and low amount of Mn dopants are coupled to give rise to such pure white emission.
91 citations
TL;DR: In this article, a chiral compound from commonly used achiral organic molecules was synthesized at room temperature and characterized by single crystal X-ray diffraction, spectroscopy (UV/Visible and FT-IR), and thermal analysis.
3 citations
TL;DR: In this article, it was shown that the organic counterion in both compounds (H2NC(N(CH3)2)2]4[Mo8O26]4− isomer can be stabilized by counterions which are either small or large.
3 citations
TL;DR: In this paper, a method to select the organic counterions to direct the synthesis towards the non-protonated or protonated anion is presented. And two new compounds (C5H16N2)3[P2Mo5O23]·4H2O (1) and (CH6N)4[H2P2M5O 23]·CH5N·4HO (2) were characterized by UV-visible absorption, IR spectroscopy and single crystal X-ray diffraction.
2 citations
TL;DR: In this paper , a hybrid decavanadate Na3(CH3NH3)3[V10O28].(CH 3NH2).14H2O was obtained by a simple synthesis in solution and the crystal structure was determined by single-crystal X-ray diffraction.
1 citations
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129 citations
TL;DR: In this paper, a green-emitting phosphor based on Ce3+/Tb3+ ions co-activated Ca2GdHf2Al3O12 (abbreviated as: CGHAO) garnet compound enabled the realization of ultra-high color rendering warm-white LEDs.
128 citations
TL;DR: In this article, a series of zero-dimensional indium-antimony (In/Sb) alloyed halide single crystals, BAPPIn2-2xSb2xCl10 (BAPP = C10H28N4, x = 0 to 1), with tunable emission was reported.
Abstract: Although single-source white emissive perovskite has emerged as a class of encouraging light-emitting material, the synthesis of lead-free halide perovskite materials with high luminous efficiency is still challenging. Here, we report a series of zero-dimensional indium-antimony (In/Sb) alloyed halide single crystals, BAPPIn2–2xSb2xCl10 (BAPP = C10H28N4, x = 0 to 1), with tunable emission. In BAPPIn1.996Sb0.004Cl10, bright yellow emission with near 100% photoluminescence quantum yield (PLQY) is yielded when it was excited at 320 nm, which turns into bright white-light emission with a PLQY of 44.0% when excited at 365 nm. Combined spectroscopy and theoretical studies reveal that the BAPP4+-associated blue emission and inorganic polyhedron–afforded orange emission function as a perfect pair of complementary colors affording white light in BAPPIn1.996Sb0.004Cl10. Moreover, the interesting afterglow behavior, together with excitation-dependent emission property, makes BAPPIn2–2xSb2xCl10 as high-performance anti-counterfeiting/information storage materials.
85 citations
81 citations
TL;DR: In this article, Sb3+-doped Cs2ZrCl6 perovskite crystals display double luminescence due to the intrinsic host self-trapped excitons and dopant-induced extrinsic self trapped exciton, respectively.
Abstract: Metal halide perovskites are highly attractive for lighting applications, but the multiexcitonic emission processes in these crystals are largely unexplored. This study presents an investigation of Sb3+-doped Cs2ZrCl6 perovskite crystals that display double luminescence due to the intrinsic host self-trapped excitons (denoted as host STEs) and dopant-induced extrinsic self-trapped excitons (denoted as dopant STEs), respectively. Steady-state and transient-state spectroscopy reveal that the host and dopant STEs can be independently charged at specific energies. Density functional theory calculations confirm that the multiexcitonic emission stems from minimal interactions between the host and dopant STEs in the zero-dimensional crystal lattice. By selective excitation of different STEs through precise control of excitation wavelength, we further demonstrate dynamic color tuning in the Cs2ZrCl6:Sb3+ crystals. The color kinetic feature offers exciting opportunities for constructing multicolor light-emitting devices and encrypting multilevel optical codes.
81 citations