Efficient and Stable Self-Assembly Blue-Emitting CsPbBr₃ Nanoplatelets with Self-Repaired Surface Defects

Abstract

The development of efficient and stable blue-emitting CsPbX3 is critically important for the balance of the three primary colors and advanced lighting and displays. Here, a single ligand passivation strategy is proposed to synthesize highly efficient self-assembly CsPbBr3 nanoplatelets (NPLs). With such a single ligand passivation strategy, the Br vacancy of the Pb–Br octahedron is eliminated effectively. The ultrafast exciton dynamic processes confirmed by transient absorption indicates the lower defect density for the self-assembly CsPbBr3 NPLs. Obvious emission improvement of the pristine CsPbBr3 NPLs was observed as the resting time increased to 24 h, which is associated with self-repaired surface defects and suppressed nonradiative recombination. Photoluminescence (PL) intensity of the CsPbBr3 NPLs in deionized water for 20 h was decreased by 40%, while PL still kept about 73% of the initial intensity even after the continuous irradiation of 395 nm UV for 30 h. The efficient and stable blue-emitting CsPbBr3 NPLs provide great opportunities to develop efficient lighting and displays.

Origin of the low-energy tail in the photoluminescence spectrum of CsPbBr3 nanoplatelets: a femtosecond transient absorption spectroscopic study

“…Therefore, it is reasonable to assign a time constant of B110 ps in the intrinsic kinetics of CsPbBr 3 NPLs to their trapped exciton lifetime. The determined B110 ps lifetime for the trapped exciton in CsPbBr 3 NPLs is quite consistent with the reports by Bohn et al 15 and He et al, 17 but is dramatically longer than in the reports by Socie et al 16 and Pan et al 51 We found that the DAS component with a lifetime of 7 AE 2 ps is contributed by the biexciton Auger recombination and the lifetime of the trapped exciton in the CsPbBr 3 NPLs is 110 AE 15 ps. To confirm the origin of the negative signals in the 2.45-2.55 eV range in the fs-TA spectrum of CsPbBr 3 NPLs at 2, 4 and 10 ps delay times, we further recorded the fs transient time profiles in hexane probed at 2.50 eV under a B3.11 eV light pump with different fluences, as shown in Fig.…”

“…Therefore, it is reasonable to assign a time constant of ∼110 ps in the intrinsic kinetics of CsPbBr 3 NPLs to their trapped exciton lifetime. The determined ∼110 ps lifetime for the trapped exciton in CsPbBr 3 NPLs is quite consistent with the reports by Bohn et al 15 and He et al , 17 but is dramatically longer than in the reports by Socie et al 16 and Pan et al 51…”

Leveraging extraordinary optical properties of inorganic lead halide perovskites for photonic luminescent solar concentrators

“…We synthesized both cubic inorganic lead halide nanocubes (NC) [16] and quantum confined inorganic lead halide nanoplates (NP) [17] to study the effects of optical environment on angular photoluminescence. The intrinsic absorption and emission of the CsPbBr 3 nanoparticles, measured by UV-vis spectroscopy, are given in Figure 3, as well as transmission electron micrographs that show particle sizing and packing.…”

Interfacial engineering to modulate surface dipoles, work functions and dielectric confinement of halide perovskites

“…In this work, we further exploit the semi-classical approach recently developed by some of us to tailor the surface dipole and work function of CsPbBr 3 . 22 This perovskite material has recently shown great promises not only for light emitting devices, such as deep blue 25 and single photon emitters, 26 but also radiation-detectors 27,28 and can be synthesized in various forms, namely single crystals, [28][29][30] thin films, 31 nanoplatelets, 25,32 colloidal quantum dots 33 and superlattices. 34,35 Ligands under consideration are phosphonate, oleate, DMSO, anilinium, anilinium -NO 2 , anilinium -OCH 3 , and three different alkylammonium ligands [ primary dodecylammonium (DA), secondary didodecylammonium (DDA), and quaternary dimethyldidodecylammonium (DMDDA)].…”