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Enhancing the performance of LARP-synthesized CsPbBr <sub/>3</sub> nanocrystal LEDs by employing a dual hole injection layer
摘要： Lead halide perovskites have been considered promising materials for optoelectronic applications owing to their superior properties. CsPbBr3 nanocrystals (NCs) with a narrow particle size distribution and a narrow emission spectrum are synthesized by ligand-assisted re-precipitation (LARP), a low-cost and facile process. In inverted CsPbBr3 NC LEDs, a dual hole injection layer (HIL) of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN)/MoO3 is introduced to enhance hole injection and transport, because HAT-CN can extract electrons easily from the hole transport layer and leave a large number of holes there. The current and power efficiencies of the optimized device with a dual HIL are 1.5- and 1.8-fold higher than those of the single HIL device. It is believed that the dual HAT-CN/MoO3 HIL effectively promotes hole injection and has promise for application in many other devices.
关键词： Ligand-assisted re-precipitation,Optoelectronic applications,Lead halide perovskites,CsPbBr3 nanocrystals,Dual hole injection layer,HAT-CN/MoO3
更新于2025-09-23 15:21:01
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Integrating Properties Modification in the Synthesis of Metal Halide Perovskites
摘要： Metal halide perovskites have attracted enormous attention and show huge potential as promising building blocks of next-generation optoelectronic devices owing to their unique optical and electrical properties. For further promoting their practical applications in various fields, the synthesis of metal halide perovskites with desired characteristics is essential to satisfy the requirements of their applications. The properties of perovskites are highly related to their crystal structures and chemical compositions. The optoelectronic properties of perovskites can be altered via decreasing their dimensionality owing to the quantum confinement effect, while enlarging the crystal size of perovskite can promote the construction of device arrays with homogenous performance. In addition, modifying the chemical composition of perovskites via alloying, doping, or controlling vacancies also greatly changes their optical and electrical properties. Thus, integrating the properties modification in the synthesis process of metal halide perovskites can not only improve the productivity of the desired perovskites but also provide a great opportunity to prepare designed crystals with predictable features. The exciting progress in the synthesis of metal halide perovskites with controllably tailored properties is summarized herein. It is hoped that these technologies can promote the development of perovskites.
关键词： properties modification,metal halide perovskites,synthesis integrating
更新于2025-09-23 15:21:01
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Two-dimensional Hybrid Halide Perovskites: Principles and Prom-ises
摘要： Hybrid halide perovskites have become the “next big thing” in emerging semiconductor materials as the past decade witnessed their successful application in high-performance photovoltaics. This resurgence has seen enormous and widespread development of the three-dimensional (3D) perovskites, spearheaded by CH3NH3PbI3. The next generation of halide perovskites, however, is characterized by reduced dimensionality perovskites, emphasizing on the two-dimensional (2D) perovskite derivatives which expand as a more diverse subgroup of semiconducting hybrids that possesses even higher tunability and excellent photophysical properties. In this perspective, we begin with a historical flashback that traces back to early reports before the “perovskite fever” and we follow this original work to its fruition in the present day, where 2D halide perovskites are on the spotlight of current research, thriving on several aspects of high-performance optoelectronics. We approach the evolution of 2D halide perovskites from a structural perspective, providing a classification for the diverse structure-types of the materials, which largely dictate the unusual physical properties observed. We sort out the 2D hybrid halide perovskite based on two key components: the inorganic layers and their modification and the organic cation diversity. As these two heterogeneous components blend, either by synthetic manipulation (shuffling the organic cations or inorganic elements) or by external stimuli (temperature and pressure), the modular perovskite structure evolves to construct crystallographically defined quantum wells (QW). The complex electronic structure that arises is sensitive to the structural features that could be in turn used as a knob to control the dielectric and optical properties the QWs. We conclude this perspective with the most notable optoelectronic device achievements that have been demonstrated to date with an eye towards future material discovery and potential technological developments.
关键词： two-dimensional (2D) perovskite derivatives,optoelectronic devices,quantum wells (QW),Hybrid halide perovskites,semiconducting hybrids
更新于2025-09-23 15:21:01
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Amplified and Multicolor Emission from Films and Interfacial Layers of Lead Halide Perovskite Nanocrystals
摘要： Lead halide perovskites are promising for energy harvesting and lighting applications. We show amplified emission from films of organic-inorganic or all inorganic lead halide perovskite nanocrystals. Also, multicolor emission is detected from interfacial layers of chloride and bromide perovskites. While amplified emission originates from spatial confinement of manifold charge carriers in films, multicolor emission emanates from interfacial ion exchanged layers. In a film, the amplified emission is averaged over a large number of nanocrystals, which prevents us from detecting any spectral narrowing. Conversely, amplified spontaneous emission (ASE) and spectral narrowing are detected from an isolated perovskite microcrystal. Interestingly, under low intensity excitation, a perovskite nanocrystal film shows unusually delayed emission, which becomes extremely fast and spatially confined at higher intensities of excitation light. By precisely detecting photoluminescence from an irradiated area and outside, we reveal the migration as well as confinement of photogenerated charge carriers in the film. The migration of charge carriers is more efficient in a film of organic-inorganic perovskites than all-inorganic perovskites.
关键词： spatial confinement,multicolor emission,interfacial ion exchange,amplified emission,Lead halide perovskites,charge carriers
更新于2025-09-23 15:21:01
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Ethanol–water-assisted room temperature synthesis of CsPbBr3/SiO2 nanocomposites with high stability in ethanol
摘要： All-inorganic halide perovskites have attracted great attention by virtue of the merits of bright emission, tunable wavelength and narrow-band emission. Despite the excellent optical features, all-inorganic halide perovskite materials have suffered from intrinsic instability, which has limited their applications in various optoelectronic devices. To mitigate the intractable issue, we demonstrated the CsPbBr3 nanoparticles decorated with smaller SiO2 nanocrystals to passivate the surface defects; SiO2 nanoparticles were applied as a barrier layer to maintain the optical property and enhance environmental stability. A facile in situ method was proposed to prepare CsPbBr3/SiO2 nanocomposites, in which an environmental ethanol/water solvent system was needed with the addition of tetraethyl orthosilicate (TEOS) as a silicon precursor. The obtained CsPbBr3/SiO2 nanocomposites have better optical characteristic and stability than bare CsPbBr3 nanoparticles. Even 70% photoluminescence intensity of as-prepared CsPbBr3/SiO2 nanocomposites can be maintained after 168 h storage in ethanol. This newly developed synthesis will open up a new route for the fabrication of optoelectronic devices in an environmentally friendly way, and the as-obtained perovskite materials with improved stability will make them great potential for multifunctional optoelectronic devices.
关键词： Ethanol–water-assisted room temperature synthesis,All-inorganic halide perovskites,High stability,CsPbBr3/SiO2 nanocomposites,Optoelectronic devices
更新于2025-09-23 15:21:01
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Low dimensional metal halide perovskites and hybrids
摘要： Organic-inorganic metal halide hybrids are an important class of crystalline materials with exceptional structural and property tunability. Recently metal halide perovskites with ABX3 structure have been extensively investigated as new generation semiconductors for various optoelectronic devices, including photovoltaic cells, light emitting diodes, photodetectors, and lasers, for their exceptional optical and electronic properties. By controlling the morphological dimensionality, low dimensional metal halide perovskites, including 2D perovskite nanoplatelets, 1D perovskite nanowires, and 0D perovskite quantum dots, have been developed to exhibit distinct properties from their bulk counterparts, due to quantum size effects. Besides ABX3 perovskites, organic-inorganic metal halide hybrids, containing the same fundamental building block of metal halide octahedra (BX6), can also be assembled to possess other types of crystallographic structures. Using appropriate organic and inorganic components, low dimensional organic-inorganic metal halide hybrids with 2D, quasi-2D, corrugated-2D, 1D, and 0D structures at the molecular level have been developed and studied. Due to the strong quantum confinement and site isolation, these low dimensional metal halide hybrids at the molecular level exhibit remarkable and unique properties that are significantly different from those of ABX3 perovskites. In light of the rapid development of low dimensional metal halide perovskites and hybrids, it is indeed timely to review the recent progress in these areas. Also, there is a need to clarify the difference between morphological low dimensional metal halide perovskites and molecular level low dimensional metal halide hybrids, as currently the terminologies of low dimensional perovskites are not appropriately used in many cases. In this review article, we discuss the synthesis, characterization, application, and computational studies of low dimensional metal halide perovskites and hybrids.
关键词： Optoelectronics,Halide Perovskites,Nanomaterials,Low dimensionality,Organic metal halide hybrids
更新于2025-09-23 15:19:57
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Review on recent advances of core-shell structured lead halide perovskites quantum dots
摘要： Lead halide perovskites have shown great potential in photovoltaic and optoelectronic devices due to their high brightness, defect tolerance, tunable emission wavelength, high color purity and near-unity luminescence quantum yield. Conversely, lead halide perovskites (LHP) show poor stability, which received strong criticism despite other promising characteristics. The poor stability attracted much research resulting in various modifications to enhance the stability and photoluminescence quantum yield (PLQY). The review outlines the basic structural and optical properties along with the conventional method of LHP synthesis and its drawbacks. Simultaneously discusses about factors responsible for instability like crystal structure, moisture, solvent, light and temperature. The review exclusively focuses on the recent research on core-shell LHP modification strategy to improve the stability and PLQY and its application in LED devices.
关键词： photoluminescence,Lead halide perovskites,stability,core-shell structure,quantum yield
更新于2025-09-23 15:19:57
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Lighta??Emitting Nanophotonic Designs Enabled by Ultrafast Laser Processing of Halide Perovskites
摘要： Nanophotonics based on resonant nanostructures and metasurfaces made of halide perovskites have become a prospective direction for efficient light manipulation at the subwavelength scale in advanced photonic designs. One of the main challenges in this field is the lack of large-scale low-cost technique for subwavelength perovskite structures fabrication preserving highly efficient luminescence. Here, unique properties of halide perovskites addressed to their extremely low thermal conductivity (lower than that of silica glass) and high defect tolerance to apply projection femtosecond laser lithography for nanofabrication with precise spatial control in all three dimensions preserving the material luminescence efficiency are employed. Namely, with CH3NH3PbI3 perovskite highly ordered nanoholes and nanostripes of width as small as 250 nm, metasurfaces with periods less than 400 nm, and nanowire lasers as thin as 500 nm, corresponding to the state-of-the-art in multistage expensive lithographical methods are created. Remarkable performance of the developed approach allows to demonstrate a number of advanced optical applications, including morphology-controlled photoluminescence yield, structural coloring, optical-information encryption, and lasing.
关键词： metasurfaces,structural coloration,lasing,halide perovskites,light emission,nanostructures
更新于2025-09-23 15:19:57
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Aira??Stable Highly Crystalline Formamidinium Perovskite 1D Structures for Ultrasensitive Photodetectors
摘要： State-of-the-art optoelectronic devices based on metal-halide perovskites demand solution-processed structures with high crystallinity, controlled crystallographic orientation, and enhanced environmental stability. Formamidinium lead iodide (α-FAPbI3) possesses a suitable bandgap of 1.48 eV and enhanced thermal stability, whereas perovskite-type polymorph (α-phase) is thermodynamically instable at ambient temperatures. Stable α-FAPbI3 perovskite 1D structure arrays with high crystallinity and ordered crystallographic orientation are developed by controlled nucleation and growth in capillary bridges. By surface functionalization with phenylethylammonium ions (PEA+), FAPbI3 wires sustain a stable α-phase after 28 day storage in the ambient environment with a relative humidity of 50%. Enhanced photoluminescence (PL) intensity and elongated PL lifetime demonstrate suppressed trap density and high crystallinity in these 1D structures, which is also reflected by the enhanced diffraction density and pure (001) crystallographic orientation in the grazing-incidence wide-angle X-ray scattering (GIWAXS) pattern. Based on these high-quality 1D structures, sensitive photodetectors are achieved with average responsivities of 5282 A W?1, average specific detectivities of more than 1.45 × 1014 Jones, and a fast response speed with a 3 dB bandwidth of 15 kHz.
关键词： metal-halide perovskites,1D structures,photodetectors,α-FAPbI3
更新于2025-09-23 15:19:57
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with Optimal Band Gap for Photovoltaics and Defect-Insensitive Blue Emission
摘要： Despite rapid progress in the power-conversion efficiency of Pb-based perovskite solar cells, both the long-term instability and Pb toxicity are still the main challenges for their commercial applications. Here, by first-principles GW calculations, we find three kinds of two-dimensional (2D) 111-type Pb-free In-based halide perovskites of the form Cs3In2X9 (X = Cl, Br, I) as promising alternatives to the star material CH3NH3PbI3 (MAPbI3) because of the following excellent electronic, optical, and transport properties: (i) The 2D In-based halide perovskites are environmentally friendly lead-free materials. (ii) Compared with MAPbX3, they have greater structural stability. (iii) As energetic photovoltaic materials, 2D Cs3In2I9 perovskites are direct-band-gap semiconductors with optimal band gaps from 1.25 eV (trilayer) to 1.47 eV (monolayer). (iv) The 2D Cs3In2X9 perovskites have ideal band structures for solid-state lighting with a wide direct-optical-band-gap range (approximately 0.94–3.54 eV), covering the whole visible-light region, and light electron (heavy hole) effective mass, which will directly enhance the defect-insensitive emission efficiency due to the localization of holes. Particularly, Cs3In2BrxCl9?x has a suitable direct optical band gap for highly desired blue emission. (v) The absorption coefficient of Cs3In2X9 is up to 7 × 104 cm?1, which is between that of GaAs (104 cm?1) and that of MAPbI3 (105 cm?1). (vi) The estimated power-conversion efficiency in Cs3In2I9 reaches 28%, which is close to that of MAPbI3 (30%). These findings pave a way for designing nontoxic, stable, and high-performance photovoltaic and light-emitting devices.
关键词： light-emitting devices,photovoltaics,halide perovskites,lead-free,two-dimensional,first-principles calculations
更新于2025-09-23 15:19:57