15243-48-8Relevant academic research and scientific papers
α-Halo Ketone for Polyhedral Perovskite Nanocrystals: Evolutions, Shape Conversions, Ligand Chemistry, and Self-Assembly
Bera, Suman,Behera, Rakesh Kumar,Pradhan, Narayan
, p. 20865 - 20874 (2020)
Bright lead halide perovskite nanocrystals, which have been extensively studied in the past 5 years, are mostly confined to a six faceted hexahedron (cube/platelet) shape. With variations of ligand, precursor, reaction temperature, and surface modification, their brightness has been enhanced and phase became stable, but ultimate nanocrystals still retained the hexahedron cube or platelet shape in most of the hot injection reactions. In contrast, by exploration of α-halo ketone in amine as a halide precursor, different shaped nanocrystals without compromising the photoluminescence quantum yield (PLQY) are reported. Confining to orthorhombic CsPbBr3, the obtained nanocrystals are stabilized by 12 facets ({200}, {020}, {112}) and led to 12 faceted rhombic dodecahedrons. These facets are absolutely different from six ({110}, {002}) equivalent facets of widely reported orthorhombic cube shaped CsPbBr3 nanocrystals. These also retained the colloidal and phase stability, as well as showed near unity PLQY. With further annealing, these are transformed to 26 faceted rhombicuboctahedrons by dissolving all their vertices. Importantly, these 12 faceted nanocrystals showed wide area self-assembly in most of the reactions. It has also been concluded that primary ammonium ions led to six faceted nanocrystals, but tertiary ammonium ions obtained in this case stabilized different group of facets. While perovskite nanocrystals were broadly confined to only nanocubes, these new nanocrystals with intense emission would certainly provide a new avenue for continuing their further research.
Tunable Hybrid Fano Resonances in Halide Perovskite Nanoparticles
Tiguntseva, Ekaterina Y.,Baranov, Denis G.,Pushkarev, Anatoly P.,Munkhbat, Battulga,Komissarenko, Filipp,Franckevi?ius, Marius,Zakhidov, Anvar A.,Shegai, Timur,Kivshar, Yuri S.,Makarov, Sergey V.
, p. 5522 - 5529 (2018)
Halide perovskites are known to support excitons at room temperatures with high quantum yield of luminescence that make them attractive for all-dielectric resonant nanophotonics and meta-optics. Here we report the observation of broadly tunable Fano resonances in halide perovskite nanoparticles originating from the coupling of excitons to the Mie resonances excited in the nanoparticles. Signatures of the photon-exciton ( hybrid ) Fano resonances are observed in dark-field spectra of isolated nanoparticles, and also in the extinction spectra of aperiodic lattices of such nanoparticles. In the latter case, chemical tunability of the exciton resonance allows reversible tuning of the Fano resonance across the 100 nm bandwidth in the visible frequency range, providing a novel approach to control optical properties of perovskite nanostructures. The proposed method of chemical tuning paves the way to an efficient control of emission properties of on-chip-integrated light-emitting nanoantennas.
Highly Photoluminescent CsPbBr3/CsPb2Br5NCs@TEOS Nanocomposite in Light-Emitting Diodes
Zhou, Yufeng,Yu, Yanxia,Zhang, Yaqian,Liu, Xiaodong,Yang, Haisheng,Liang, Xiaojuan,Xia, Wei,Xiang, Weidong
, p. 3814 - 3822 (2021)
All-inorganic halide perovskite (CsPb2Br5) nanocrystals (NCs) have received widespread attention owing to their unique photoelectric properties. This work reports a novel strategy to control the phase transition from CsPbBr3 to CsPb2Br5 and investigates the effects of different treatment times and treatment temperatures on perovskite NCs formation. By controlling the volume of tetraethoxysilane (TEOS) added, the formation of different phases of perovskite powder can be well controlled. In addition, a white light-emitting diode (WLED) device is designed by coupling the CsPbBr3/CsPbBr3-CsPb2Br5 NCs@TEOS nanocomposite and CaAlSiN3:Eu2+ commercial phosphor with a 460 nm InGaN blue chip, exhibiting a high luminous efficiency of 57.65 lm/W, color rendering index (CRI) of 91, and a low CCT of 5334 K. The CIE chromaticity coordinates are (0.3363, 0.3419). This work provides a new strategy for the synthesis of CsPbBr3/CsPbBr3-CsPb2Br5 NCs@TEOS nanocomposite, which can be applied to the field of WLEDs and display devices.
Photoinduced Anion Exchange in Cesium Lead Halide Perovskite Nanocrystals
Parobek, David,Dong, Yitong,Qiao, Tian,Rossi, Daniel,Son, Dong Hee
, p. 4358 - 4361 (2017)
Cesium lead halide (CsPbX3) perovskite nanocrystals (NCs) possess the unique capability of post-synthesis anion exchange providing facile tunability of the optical properties, which is usually achieved by mixing NCs with reactive anion precursors. In this work, we show that the controllable anion exchange can be achieved in a dihalomethane solution of CsPbX3 NC in the absence of any spontaneously reacting anion source using photoexcitation of CsPbX3 NCs as the triggering mechanism for the halide ion exchange. The reaction begins with the photoinduced electron transfer from CsPbX3 NCs to dihalomethane solvent molecules producing halide ions via reductive dissociation, which is followed by anion exchange. The reaction proceeds only in the presence of excitation light and the rate and extent of reaction can be controlled by varying the light intensity. Furthermore, the asymptotic extent of reaction under continuous excitation can be controlled by varying the wavelength of light that self-limits the reaction when light becomes off-resonance with the absorption of NCs. The light-controlled anion exchange demonstrated here can be utilized to pattern the post-synthesis chemical transformation of CsPbX3 NCs, not readily achievable using typical methods of anion exchange.
Templated-Assembly of CsPbBr3 Perovskite Nanocrystals into 2D Photonic Supercrystals with Amplified Spontaneous Emission
D?blinger, Markus,Feil, Maximilian W.,Feldmann, Jochen,Garcia-Pomar, Juan Luis,Huang, He,Liz-Marzán, Luis M,Manzi, Aurora,Mihi, Agustín,Polavarapu, Lakshminarayana,Vila-Liarte, David
, p. 17750 - 17756 (2020)
Perovskite nanocrystals (NCs) have revolutionized optoelectronic devices because of their versatile optical properties. However, controlling and extending these functionalities often requires a light-management strategy involving additional processing steps. Herein, we introduce a simple approach to shape perovskite nanocrystals (NC) into photonic architectures that provide light management by directly shaping the active material. Pre-patterned polydimethylsiloxane (PDMS) templates are used for the template-induced self-assembly of 10 nm CsPbBr3 perovskite NC colloids into large area (1 cm2) 2D photonic crystals with tunable lattice spacing, ranging from 400 nm up to several microns. The photonic crystal arrangement facilitates efficient light coupling to the nanocrystal layer, thereby increasing the electric field intensity within the perovskite film. As a result, CsPbBr3 2D photonic crystals show amplified spontaneous emission (ASE) under lower optical excitation fluences in the near-IR, in contrast to equivalent flat NC films prepared using the same colloidal ink. This improvement is attributed to the enhanced multi-photon absorption caused by light trapping in the photonic crystal.
CsPbBr3 nanocrystal saturable absorber for mode-locking ytterbium fiber laser
Zhou, Yan,Hu, Zhiping,Li, Yue,Xu, Jianqiu,Tang, Xiaosheng,Tang, Yulong
, (2016)
Cesium lead halide perovskite nanocrystals (CsPbX3, X = Cl, Br, I) have been reported as efficient light-harvesting and light-emitting semiconductor materials, but their nonlinear optical properties have been seldom touched upon. In this paper, we prepare layered CsPbBr3 nanocrystal films and characterize their physical properties. Broadband linear absorption from ～0.8 to over 2.2 μm and nonlinear optical absorption at the 1-μm wavelength region are measured. The CsPbBr3 saturable absorber (SA), manufactured by drop-casting of colloidal CsPbBr3 liquid solution on a gold mirror, shows modulation depth and saturation intensity of 13.1% and 10.7 MW/cm2, respectively. With this SA, mode-locking operation of a polarization-maintained ytterbium fiber laser produces single pulses with duration of ～216 ps, maximum average output power of 10.5 mW, and the laser spectrum is centered at ～1076 nm. This work shows that CsPbBr3 films can be efficient SA candidates for fiber lasers and also have great potential to become broadband linear and nonlinear optical materials for photonics and optoelectronics.
Time-dependent transformation routes of perovskites CsPbBr3and CsPbCl3under high pressure
Katrusiak, Andrzej,St?hl, Kenny,Szafrański, Marek
, p. 10769 - 10779 (2021)
All-inorganic halide perovskites are prospective materials for diverse applications in photovoltaic and optoelectronic devices. Their high performance is associated with good operational stability, which is the key problem of hybrid organic-inorganic perovskites. However, for these materials only fragmentary information is available on the mechanical robustness and response to external stress, fundamentally important for strain engineering in multilayers, pressure-assisted technologies, and flexible panels applications. Here we show that all-inorganic perovskites CsPbX3 (where X = Cl, Br) undergo various types of pressure-induced transformations, including reversible phase transitions, irreversible chemical reactions reducing the dimensionality of PbX6 frameworks, and amorphization. The transformation routes depend on the mode of the applied stress and are related to the kinetics of transitions to the most stable phases. The slow-kinetics transformations in a moderate pressure range of technological importance, between 0.5 and 1.5 GPa, can require days or even weeks, depending on the sample quality and external stimuli. The pressure-induced narrowing and widening of energy gaps has been explained by the mechanism combining Pb-X bond lengths and PbX6 octahedra tilts with the electronic structure of the crystals.
Centimeter-sized inorganic lead halide perovskite CsPbBr3 crystals grown by an improved solution method
Zhang, Hongjian,Liu, Xin,Dong, Jiangpeng,Yu, Hui,Zhou, Ce,Zhang, Binbin,Xu, Yadong,Jie, Wanqi
, p. 6426 - 6431 (2017)
As a member of the lead-halide perovskite family, inorganic perovskite CsPbBr3 exhibits excellent optical and electrical properties with higher stability to the environment. However, former efforts to obtain large-size CsPbBr3 single crystals with satisfactory quality using low temperature solution methods reached limited results. In this work, we have studied the growth of CsPbBr3 crystals using the antisolvent vapor-assisted crystallization (AVC) method. By adjusting the mole ratio of PbBr2 and CsBr, the phase diagram of the final products is acquired. Five regions are identified, including the Cs4PbBr6 single phase region, Cs4PbBr6 and CsPbBr3 two phases region, CsPbBr3 single phase region, CsPbBr3 and PbBr2· 2[(CH3)2SO] metastable two phases region, and CsPbBr3 and PbBr2·2[(CH3)2SO] two phases region. Three methods are adopted to improve the size and crystalline quality of CsPbBr3. The growth rate is effectively tailored by diluting the antisolvent MeOH solution using DMSO to reduce the MeOH vapor pressure. Centimeter-size bright CsPbBr3 crystals have been obtained. The room temperature bandgap of CsPbBr3 is estimated at ～2.29 eV by the transmission spectra. The photoluminescence spectra show two strong emission peaks, located at 530 and 555 nm, respectively, which are related to the free and bond excitons. The resistivity is as large as 2.1 × 109 Ω· cm. Hall effect measurements demonstrate the CsPbBr3 is p-type conductivity with a hole carrier concentration of 4.55 × 107 cm-3 and the mobility of 143 cm2 V-1 s-1. The resulting Au/CsPbBr3/Au device exhibits strong photoresponse to optical light, with an on-off ratio of two orders under a light emitting diode (～1 mW/cm2) with a wavelength of 365-420 nm. Our research would shed more light on the growth and the photoresponse properties of CsPbBr3 crystals.
CsPbBr3nanowire polarized light-emitting diodes through mechanical rubbing
Wei, Yaping,Xu, Yinyan,Wang, Qian,Wang, Jianyue,Lu, Hongbo,Zhu, Jun
, p. 5413 - 5416 (2020)
Anisotropic films composed of aligned CsPbBr3nanowires (NWs) have been successfully fabricated using a mechanical rubbing method. The films with a dense and uniform morphology show polarization photoluminescence (PL) behavior. Combined with an optimal device structure, a polarized light-emitting diode (LED) with a turn-on voltage as low as 6.5 V was obtained.
High-sensitivity X-ray detectors based on solution-grown caesium lead bromide single crystals
Zhang, Hongjian,Wang, Fangbao,Lu, Yufei,Sun, Qihao,Xu, Yadong,Zhang, Bin-Bin,Jie, Wanqi,Kanatzidis, Mercouri G.
, p. 1248 - 1256 (2020)
X-ray detection is of great significance for medical diagnostics, industrial non-destructive inspection, nuclear plants and scientific research. However, high sensitivity is needed for X-ray detectors to reduce the radiation dose applied to human bodies for the applications of medical imaging and security checks. Here, we reported sensitive X-ray detectors made of solution-grown inorganic lead perovskite CsPbBr3 single crystals and the synthesis of high-quality inorganic lead perovskite CsPbBr3 single crystals using an improved low temperature solution method, which exhibited high transmittance, mobility and mobility-lifetime products. By designing the detector in an asymmetric electrode configuration, ion migration was effectively suppressed under a high voltage with a low dark current and an outstanding photoresponse. The optimized detector exhibited high sensitivity of 1256 μC Gy-1 cm-2 for 80 kVp X-ray detection under a relatively low electric field of 20 V mm-1, which was 60 times higher than that of commercially used α-Se detectors. Due to its facile synthesis, low cost, long-term stability, and high detection sensitivity, CsPbBr3 is expected to be an outstanding candidate for commercialized sensitive X-ray detectors.
