Ultra-Stable CsPbBr3 Nanocrystals with Lead-Carboxylate/SiO2 Encapsulation for LED Application

Author(s):  
Yixuan Liu ◽  
Lulu Zhang ◽  
Xuemi Long ◽  
Panpan Jiang ◽  
Chong Geng ◽  
...  

Perovskite nanocrystals (PNCs) are promising luminescent materials but suffer servere stability issue due to their ionic surface nature. SiO2 encapsulation is widely adopted for stabilizing PNCs in LED lighting and...

Author(s):  
Naji Vahedigharehchopogh ◽  
Orhan Kıbrıslı ◽  
Erdinc Erol ◽  
Miray Çelikbilek Ersundu ◽  
Ali Erçin Ersundu

Increment of forgery in documents and authentic products have aroused the search for new high-end anti-counterfeiting strategies. Various chameleon-like luminescent materials such as up-conversion nano particles or perovskite nanocrystals have...


Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 59 ◽  
Author(s):  
Ziqian He ◽  
Caicai Zhang ◽  
Yajie Dong ◽  
Shin-Tson Wu

Recent advances in perovskite nanocrystals-enhanced solid-state lighting (SSL) and liquid-crystal displays (LCDs) are reviewed. We first discuss the development, optical properties, and stability issue of materials, and then we evaluate the performance of SSL and LCDs with perovskite downconverters adopted. In SSL performance evaluation, we investigate the fitting-curve effect in calculations and optimizations where simple Gaussian fitting and precise fitting are compared in detail, and we further optimize for highly efficient, good color-rendering, and human-healthy SSL sources. For LCD performance evaluation, we study the intrinsic tradeoffs between total light efficiency and color gamut coverage. Through optimizations using real line shapes, Rec. 2020 standard coverage as large as 92.8% can be achieved through hybrid integration. Finally, we briefly discuss two future challenges: materials development and device integration. We believe the emerging perovskite nanocrystals are highly promising for next-generation SSL and LCDs.


Author(s):  
M. Pan ◽  
J.M. Cowley

Electron microdiffraction patterns, obtained when a small electron probe with diameter of 10-15 Å is directed to run parallel to and outside a flat crystal surface, are sensitive to the surface nature of the crystals. Dynamical diffraction calculations have shown that most of the experimental observations for a flat (100) face of a MgO crystal, such as the streaking of the central spot in the surface normal direction and (100)-type forbidden reflections etc., could be explained satisfactorily by assuming a modified image potential field outside the crystal surface. However the origin of this extended surface potential remains uncertain. A theoretical analysis by Howie et al suggests that the surface image potential should have a form different from above-mentioned image potential and also be smaller by several orders of magnitude. Nevertheless the surface potential distribution may in practice be modified in various ways, such as by the adsorption of a monolayer of gas molecules.


Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.


2020 ◽  
Author(s):  
Goutam Ghosh ◽  
Amitava Patra ◽  
Arnab Ghosh ◽  
Srijon Ghosh

2019 ◽  
pp. 71-77
Author(s):  
Vladimir V. Vorozhikhin ◽  
Eugenia L. Moreva ◽  
Vladimir G. Starovoytov ◽  
Igor G. Tyutyunnik

The purpose of this paper is an investigation of LEDs illumination experience at US-based aerodromes with an assessment of its feasibility and its necessity in Russia. The following methods were used: the analysis of aerodrome lighting requirements; the review and the analysis of development features in aerodrome LEDs illumination; the experience analysis of LEDs illumination of US-based aerodromes; the deductive analysis and the assessment synthesis of feasibility and necessity of US experience in LEDs illumination at Russian-based aerodromes. The following results were achieved: – The analysis of issues and opportunities was conducted for development of LEDs illumination at US-based aerodromes and of American experts’ recommendations for its use; – The cases were taken for use and assessment of development in LEDs illumination at US-based aerodromes; – The review and the analysis were conducted in relation to a developing market of LEDs illumination at Russian-based aerodromes. The main conclusion is that the US experience will improve quality and reliability of service provided in air transportation, comfort, and safety of Russian flights, as well as competitiveness of Russian- based airports and airlines (indirectly).


2016 ◽  
Vol 18 (2) ◽  
pp. 157-168
Author(s):  
N. V. Kozel ◽  
E. E. Manankina ◽  
Y. V. Viazau ◽  
I. A. Dremuk ◽  
S. M. Savina ◽  
...  

2019 ◽  
Author(s):  
Michael Worku ◽  
Yu Tian ◽  
Chenkun Zhou ◽  
Haoran Lin ◽  
Maya Chaaban ◽  
...  

Metal halide perovskite nanocrystals (NCs) have emerged as a new generation light emitting materials with narrow emissions and high photoluminescence quantum efficiencies (PLQEs). Various types of perovskite NCs, e.g. platelets, wires, and cubes, have been discovered to exhibit tunable emissions across the whole visible spectral region. Despite remarkable advances in the field of metal halide perovskite NCs over the last few years, many nanostructures in inorganic NCs have yet been realized in metal halide perovskites and producing highly efficient blue emitting perovskite NCs remains challenging and of great interest. Here we report for the first time the discovery of highly efficient blue emitting cesium lead bromide perovskite (CsPbBr3) NCs with hollow structures. By facile solution processing of cesium lead bromide perovskite precursor solution containing additional ethylenediammonium bromide and sodium bromide, in-situ formation of hollow CsPbBr3 NCs with controlled particle and pore sizes is realized. Synthetic control of hollow nanostructures with quantum confinement effects results in color tuning of CsPbBr3 NCs from green to blue with high PLQEs of up to 81 %.<br><div><br></div>


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