Mixed Conductivity of Hybrid Halide Perovskites: Emerging Opportunities and Challenges

Hybrid halide perovskites feature mixed ionic-electronic conductivities that are enhanced under device operating conditions. This has been extensively investigated over the past years by a wide range of techniques. In particular, the suppression of ionic motion by means of material and device engineering has been of increasing interest, such as through compositional engineering, using molecular modulators as passivation agents, and low-dimensional perovskite materials in conjunction with alternative device architectures to increase the stabilities under ambient and operating conditions of voltage bias and light. While this remains an ongoing challenge for photovoltaics and light-emitting diodes, mixed conductivities offer opportunities for hybrid perovskites to be used in other technologies, such as rechargeable batteries and resistive switches for neuromorphic memory elements. This article provides an overview of the recent developments with a perspective on the emerging utility in the future.

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The dark exciton ground state promotes photon-pair emission in individual perovskite nanocrystals

Nature Communications ◽

10.1038/s41467-020-19740-7 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Philippe Tamarat ◽

Lei Hou ◽

Jean-Baptiste Trebbia ◽

Abhishek Swarnkar ◽

Louis Biadala ◽

...

Keyword(s):

Near Infrared ◽

Exciton State ◽

Lead Iodide ◽

Electron Hole ◽

Light Emitting ◽

Perovskite Nanocrystals ◽

Light Emitting Devices ◽

Optical And Electronic Properties ◽

Wide Range ◽

Halide Perovskites

AbstractCesium lead halide perovskites exhibit outstanding optical and electronic properties for a wide range of applications in optoelectronics and for light-emitting devices. Yet, the physics of the band-edge exciton, whose recombination is at the origin of the photoluminescence, is not elucidated. Here, we unveil the exciton fine structure of individual cesium lead iodide perovskite nanocrystals and demonstrate that it is governed by the electron-hole exchange interaction and nanocrystal shape anisotropy. The lowest-energy exciton state is a long-lived dark singlet state, which promotes the creation of biexcitons at low temperatures and thus correlated photon pairs. These bright quantum emitters in the near-infrared have a photon statistics that can readily be tuned from bunching to antibunching, using magnetic or thermal coupling between dark and bright exciton sublevels.

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Performance and Stability Improvements in Metal Halide Perovskite with Intralayer Incorporation of Organic Additives

Journal of Materials Chemistry A ◽

10.1039/d1ta05252g ◽

2021 ◽

Author(s):

Yanan Li ◽

Matthew Dailey ◽

Patrick Lohr ◽

Adam Printz

Keyword(s):

Thin Film ◽

Thin Film Transistors ◽

Metal Halide ◽

Organic Additives ◽

Semiconducting Materials ◽

Light Emitting ◽

Metal Halide Perovskite ◽

Wide Range ◽

Halide Perovskites ◽

Halide Perovskite

Metal halide perovskites are emerging semiconducting materials with a wide range of applications, including photovoltaics, thin-film transistors, and light-emitting diodes. A key advantage of perovskites over more established semiconductor technologies...

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Recent Developments in Lead and Lead-Free Halide Perovskite Nanostructures towards Photocatalytic CO2 Reduction

Nanomaterials ◽

10.3390/nano10122569 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2569

Author(s):

Chaitanya B. Hiragond ◽

Niket S. Powar ◽

Su-Il In

Keyword(s):

High Performance ◽

High Surface ◽

Co2 Reduction ◽

Value Added ◽

Wide Range ◽

Recent Developments ◽

Metal Organic ◽

Halide Perovskites ◽

Halide Perovskite ◽

Crystallographic Defects

Perovskite materials have been widely considered as emerging photocatalysts for CO2 reduction due to their extraordinary physicochemical and optical properties. Perovskites offer a wide range of benefits compared to conventional semiconductors, including tunable bandgap, high surface energy, high charge carrier lifetime, and flexible crystal structure, making them ideal for high-performance photocatalytic CO2 reduction. Notably, defect-induced perovskites, for example, crystallographic defects in perovskites, have given excellent opportunities to tune perovskites’ catalytic properties. Recently, lead (Pb) halide perovskite and their composites or heterojunction with other semiconductors, metal nanoparticles (NPs), metal complexes, graphene, and metal-organic frameworks (MOFs) have been well established for CO2 conversion. Besides, various halide perovskites have come under focus to avoid the toxicity of lead-based materials. Therefore, we reviewed the recent progress made by Pb and Pb-free halide perovskites in photo-assisted CO2 reduction into useful chemicals. We also discussed the importance of various factors like change in solvent, structure defects, and compositions in the fabrication of halide perovskites to efficiently convert CO2 into value-added products.

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Low-Dimensional Phase Suppression and Defect Passivation of Quasi-2D Perovskites for Efficient Electroluminescence and Low-Threshold Amplified Spontaneous Emission

Nanoscale ◽

10.1039/d1nr06549a ◽

2021 ◽

Author(s):

Guangrong Jin ◽

Tanghao Liu ◽

Yuanzhao Li ◽

Jiadong Zhou ◽

Dengliang Zhang ◽

...

Keyword(s):

Binding Energy ◽

Spontaneous Emission ◽

Quantum Confinement ◽

Quantum Confinement Effect ◽

Light Emitting ◽

Large Exciton Binding Energy ◽

Defect Passivation ◽

Low Threshold ◽

Halide Perovskites ◽

Low Dimensional

Quasi-2D metal halide perovskites are promising candidates for light-emitting application owing to their large exciton binding energy and strong quantum confinement effect. Usually, quasi-2D perovskites are composed of multiple phases...

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A review of low-dimensional metal halide perovskites for blue light emitting diodes

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2021.160727 ◽

2021 ◽

pp. 160727

Author(s):

Xiaodong Peng ◽

Cheng Yan ◽

Fengjun Chun ◽

Wen Li ◽

Xuehai Fu ◽

...

Keyword(s):

Blue Light ◽

Light Emitting Diodes ◽

Metal Halide ◽

Light Emitting ◽

Halide Perovskites ◽

Low Dimensional

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Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

10.21203/rs.3.rs-92649/v1 ◽

2020 ◽

Author(s):

Max Karlsson ◽

Ziyue Yi ◽

Sebastian Reichert ◽

Xiyu Luo ◽

Weihua Lin ◽

...

Keyword(s):

High Efficiency ◽

Light Emitting Diodes ◽

Three Dimensional ◽

Blue Emission ◽

Chloride Content ◽

Practical Implementation ◽

Ion Migration ◽

Light Emitting ◽

Wide Range ◽

Halide Perovskites

Abstract Bright and efficient blue emission is key to further development of metal halide perovskite light-emitting diodes. Although modifying bromide/chloride composition is straightforward to achieve blue emission, practical implementation of this strategy has been challenging due to poor colour stability and severe photoluminescence quenching. Both detrimental effects become increasingly prominent in perovskites with the high chloride content that is desired to produce blue emission. Here, we solve these critical challenges in mixed halide perovskites and demonstrate spectrally stable blue perovskite light-emitting diodes (PeLEDs) over a wide range of emission wavelengths from 490 to 451 nanometres. The emission colour is directly tuned by modifying the halide composition. Particularly, our blue and deep-blue PeLEDs based on three-dimensional perovskites show high EQE values of 11.0% and 5.5% with emission peaks at 477 and 467 nm, respectively. These achievements are enabled by a vapour-assisted crystallization technique, which largely mitigates local compositional heterogeneity and ion migration.

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Recent Progresses on Metal Halide Perovskite-Based Material as Potential Photocatalyst

Catalysts ◽

10.3390/catal10060709 ◽

2020 ◽

Vol 10 (6) ◽

pp. 709 ◽

Cited By ~ 4

Author(s):

Bianca-Maria Bresolin ◽

Yuri Park ◽

Detlef W. Bahnemann

Keyword(s):

Metal Halide ◽

Quantum Yields ◽

Light Emitting ◽

Contaminant Degradation ◽

Luminescent Solar Concentrators ◽

Metal Halide Perovskite ◽

Recent Developments ◽

Fast Development ◽

Halide Perovskites ◽

New Generation

Recent years have witnessed an incredibly high interest in perovskite-based materials. Among this class, metal halide perovskites (MHPs) have attracted a lot of attention due to their easy preparation and excellent opto-electronic properties, showing a remarkably fast development in a few decades, particularly in solar light-driven applications. The high extinction coefficients, the optimal band gaps, the high photoluminescence quantum yields and the long electron–hole diffusion lengths make MHPs promising candidates in several technologies. Currently, the researchers have been focusing their attention on MHPs-based solar cells, light-emitting diodes, photodetectors, lasers, X-ray detectors and luminescent solar concentrators. In our review, we firstly present a brief introduction on the recent discoveries and on the remarkable properties of metal halide perovskites, followed by a summary of some of their more traditional and representative applications. In particular, the core of this work was to examine the recent progresses of MHPs-based materials in photocatalytic applications. We summarize some recent developments of hybrid organic–inorganic and all-inorganic MHPs, recently used as photocatalysts for hydrogen evolution, carbon dioxide reduction, organic contaminant degradation and organic synthesis. Finally, the main limitations and the future potential of this new generation of materials have been discussed.

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Mixed halide perovskites for spectrally stable and high-efficiency blue light-emitting diodes

Nature Communications ◽

10.1038/s41467-020-20582-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Max Karlsson ◽

Ziyue Yi ◽

Sebastian Reichert ◽

Xiyu Luo ◽

Weihua Lin ◽

...

Keyword(s):

Blue Light ◽

High Efficiency ◽

Light Emitting Diodes ◽

Three Dimensional ◽

Blue Emission ◽

Chloride Content ◽

Practical Implementation ◽

Light Emitting ◽

Wide Range ◽

Halide Perovskites

AbstractBright and efficient blue emission is key to further development of metal halide perovskite light-emitting diodes. Although modifying bromide/chloride composition is straightforward to achieve blue emission, practical implementation of this strategy has been challenging due to poor colour stability and severe photoluminescence quenching. Both detrimental effects become increasingly prominent in perovskites with the high chloride content needed to produce blue emission. Here, we solve these critical challenges in mixed halide perovskites and demonstrate spectrally stable blue perovskite light-emitting diodes over a wide range of emission wavelengths from 490 to 451 nanometres. The emission colour is directly tuned by modifying the halide composition. Particularly, our blue and deep-blue light-emitting diodes based on three-dimensional perovskites show high EQE values of 11.0% and 5.5% with emission peaks at 477 and 467 nm, respectively. These achievements are enabled by a vapour-assisted crystallization technique, which largely mitigates local compositional heterogeneity and ion migration.

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Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096230 ◽

1972 ◽

Vol 30 ◽

pp. 596-597

Author(s):

David A. Ansley

Keyword(s):

Spherical Aberration ◽

Focal Length ◽

Chromatic Aberration ◽

Spatial Filter ◽

Operating Conditions ◽

Objective Lens ◽

List Type ◽

Spatial Filters ◽

Transmission Electron ◽

Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

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Reduction of carbon impurities in aluminium nitride from time-resolved chemical vapour deposition using trimethylaluminum

10.26434/chemrxiv.11910735.v2 ◽

2020 ◽

Author(s):

Polla Rouf ◽

Pitsiri Sukkaew ◽

Lars Ojamäe ◽

Henrik Pedersen

Keyword(s):

Chemical Vapour Deposition ◽

Vapour Deposition ◽

Chemical Vapour ◽

Aluminium Nitride ◽

Methyl Groups ◽

Time Resolved ◽

Thermally Induced ◽

Light Emitting ◽

Carbon Impurities ◽

Wide Range

Aluminium nitride (AlN) is a semiconductor with a wide range of applications from light emitting diodes to high frequency transistors. Electronic grade AlN is routinely deposited at 1000 °C by chemical vapour deposition (CVD) using trimethylaluminium (TMA) and NH3 while low temperature CVD routes to high quality AlN are scarce and suffer from high levels of carbon impurities in the film. We report on an ALD-like CVD approach with time-resolved precursor supply where thermally induced desorption of methyl groups from the AlN surface is enhanced by the addition of an extra pulse, H2, N2 or Ar between the TMA and NH3 pulses. The enhanced desorption allowed deposition of AlN films with carbon content of 1 at. % at 480 °C. Kinetic- and quantum chemical modelling suggest that the extra pulse between TMA and NH3 prevents re-adsorption of desorbing methyl groups terminating the AlN surface after the TMA pulse.

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