Lasing in robust cesium lead halide perovskite nanowires

The rapidly growing field of nanoscale lasers can be advanced through the discovery of new, tunable light sources. The emission wavelength tunability demonstrated in perovskite materials is an attractive property for nanoscale lasers. Whereas organic–inorganic lead halide perovskite materials are known for their instability, cesium lead halides offer a robust alternative without sacrificing emission tunability or ease of synthesis. Here, we report the low-temperature, solution-phase growth of cesium lead halide nanowires exhibiting low-threshold lasing and high stability. The as-grown nanowires are single crystalline with well-formed facets, and act as high-quality laser cavities. The nanowires display excellent stability while stored and handled under ambient conditions over the course of weeks. Upon optical excitation, Fabry–Pérot lasing occurs in CsPbBr3 nanowires with an onset of 5 μJ cm−2 with the nanowire cavity displaying a maximum quality factor of 1,009 ± 5. Lasing under constant, pulsed excitation can be maintained for over 1 h, the equivalent of 109 excitation cycles, and lasing persists upon exposure to ambient atmosphere. Wavelength tunability in the green and blue regions of the spectrum in conjunction with excellent stability makes these nanowire lasers attractive for device fabrication.

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Improving the Aesthetics and Performance of Perovskite Materials for Photovoltaics

10.23889/suthesis.58752 ◽

2021 ◽

Author(s):

◽

Tamara D. McFarlane

Keyword(s):

Solar Cells ◽

Organic Dyes ◽

Perovskite Solar Cells ◽

Colour Change ◽

Ambient Conditions ◽

Perovskite Materials ◽

Device Efficiency ◽

Lower Light ◽

Halide Perovskite ◽

Lead Halide

Within the last decade, lead halide perovskite solar cells have rapidly evolved to the cusp of commercialisation. Current record device efficiencies have surpassed 25% however; a principal limitation of these materials is their instability on exposure to ambient conditions. Methylammonium lead tri-bromide (MAPbBr3) perovskite has shown superior stability over other lead halide perovskite materials, yet the efficiencies of MAPbBr3 devices are significantly lower with a record efficiency of 10.4%. This research investigates the treatment of MAPbBr3 perovskite solar cells with organic dyes of complementary absorbance in a bid to maximise the light harvesting, increase the photocurrent and improve the device efficiency. Initial investigations focused on developing an optimised build method capable of manufacturing MAPbBr3 devices which consistently achieve above 1% efficiency. The optical characterisation of six organic dyes revealed a red indoline dye, D205 and a blue squaraine, SQ2 (which both absorb strongly between 300-700 nm) would offer the best complementary absorbance to MAPbBr3 perovskite. On adding the dyes, the perovskite layer underwent an evident colour change highlighting the potential for coloured perovskite cells which could be beneficial for building-integrated applications. MAPbBr3 cells co-sensitised using a novel method (which sensitises the film after perovskite crystallisation) show improved efficiency (2.6% SQ2, 3.1% D205) over perovskite-only devices (2%) with a 10% photocurrent contribution from the dye. Whilst increases in the photocurrent are observed with co-sensitisation, increased device efficiencies are mainly derived from improvements in the fill factor. We also see lower series resistance and increased photoluminescence lifetime with co-sensitisation where control and co-sensitised MAPbBr3 thin-films produce average lifetimes of 0.44 ns and 0.80 ns, respectively. Further investigation has revealed the dye solvent, toluene, and the dye both help to improve device performance acting as both a treatment and a second sensitiser in the device by passivating defects and lowering recombination losses whilst providing additional photocurrent through increased absorbance. As a result, co-sensitised devices show slower recombination kinetics resulting in increased open-circuit voltage under lower light levels. These effects have proven beneficial for thicker co-sensitised devices (>0.7 µm) where they have often translated into large increases in device efficiency. In future, this may be beneficial for indoor or lower light level PV systems including within the rapidly expanding internet of things market.

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Individual lead halide perovskite nanocrystals as quantum light sources

10.29363/nanoge.icqd.2020.011 ◽

2020 ◽

Author(s):

Brahim LOUNIS

Keyword(s):

Light Sources ◽

Perovskite Nanocrystals ◽

Halide Perovskite ◽

Individual Lead ◽

Lead Halide

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Bromopropane as a Novel Bromine Precursor for the Completely Amine Free Colloidal Synthesis of Ultra-Stable and Highly Luminescent Green-Emitting Cesium Lead Bromide (CsPbBr3) Perovskite Nanocrystals

Nanoscale ◽

10.1039/d1nr03560f ◽

2021 ◽

Author(s):

Syed Akhil ◽

V.G.Vasavi Dutt ◽

Nimai Mishra

Keyword(s):

Optoelectronic Devices ◽

Colloidal Synthesis ◽

Ambient Conditions ◽

Active Materials ◽

Perovskite Nanocrystals ◽

Lead Bromide ◽

Halide Perovskite ◽

Lead Halide ◽

Poor Stability

Recently lead halide perovskite nanocrystals (PNCs) have attracted intense interest as promising active materials for optoelectronic devices. However, their extensive applications are still hampered by poor stability in ambient conditions....

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Solid-State NMR and NQR Spectroscopy of Lead-Halide Perovskite Materials

Journal of the American Chemical Society ◽

10.1021/jacs.0c07338 ◽

2020 ◽

Vol 142 (46) ◽

pp. 19413-19437

Author(s):

Laura Piveteau ◽

Viktoriia Morad ◽

Maksym V. Kovalenko

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Perovskite Materials ◽

Halide Perovskite ◽

Lead Halide

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Near Unity PLQY and High Stability of Barium Thiocyanate Based All-Inorganic Perovskites and Their Applications in White Light-Emitting Diodes

Photonics ◽

10.3390/photonics8060209 ◽

2021 ◽

Vol 8 (6) ◽

pp. 209

Author(s):

Gopi Chandra Adhikari ◽

Saroj Thapa ◽

Yang Yue ◽

Hongyang Zhu ◽

Peifen Zhu

Keyword(s):

White Light ◽

Large Scale ◽

Light Emitting Diode ◽

Photophysical Properties ◽

Environmental Stability ◽

Color Temperature ◽

Ambient Atmosphere ◽

Light Emitting ◽

Halide Perovskite ◽

Lead Halide

All-inorganic lead halide perovskite (CsPbX3) nanocrystals (NCs) have emerged as a highly promising new generation of light emitters due to their extraordinary photophysical properties. However, the performance of these semiconducting NCs is undermined due to the inherent toxicity of lead and long-term environmental stability. Here, we report the addition of B-site cation and X-site anion (pseudo-halide) concurrently using Ba(SCN)2 (≤50%) in CsPbX3 NCs to reduce the lead and improve the photophysical properties and stability. The as-grown particles demonstrated an analogous structure with an almost identical lattice constant and a fluctuation of particle size without altering the morphology of particles. Photoluminescence quantum yield is enhanced up to near unity (~98%) by taking advantage of concomitant doping at the B- and X-site of the structure. Benefitted from the defect reductions and stronger bonding interaction between Pb2+ and SCN− ions, Ba(SCN)2-based NCs exhibit improved stability towards air and moisture compared to the host NCs. The doped NCs retain higher PLQY (as high as seven times) compared to the host NCs) when stored in an ambient atmosphere for more than 176 days. A novel 3D-printed multiplex color conversion layer was used to fabricate a white light-emitting diode (LED). The obtained white light shows a correlated color temperature of 6764 K, a color rendering index of 87, and luminous efficacy of radiation of 333 lm/W. In summary, this work proposes a facile route to treat sensitive lead halide perovskite NCs and to fabricate LEDs by using a low-cost large-scale 3-D printing method, which would serve as a foundation for fabricating high-quality optoelectronic devices for near future lighting technologies.

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Lead-Free Halide Double Perovskites: A Review of the Structural, Optical, and Stability Properties as Well as Their Viability to Replace Lead Halide Perovskites

Metals ◽

10.3390/met8090667 ◽

2018 ◽

Vol 8 (9) ◽

pp. 667 ◽

Cited By ~ 24

Author(s):

Edson Meyer ◽

Dorcas Mutukwa ◽

Nyengerai Zingwe ◽

Raymond Taziwa

Keyword(s):

Solar Cells ◽

Perovskite Solar Cells ◽

Lead Free ◽

Double Perovskites ◽

Stability Properties ◽

Perovskite Materials ◽

Halide Perovskites ◽

Halide Perovskite ◽

Light Absorbers ◽

Lead Halide

Perovskite solar cells employ lead halide perovskite materials as light absorbers. These perovskite materials have shown exceptional optoelectronic properties, making perovskite solar cells a fast-growing solar technology. Perovskite solar cells have achieved a record efficiency of over 20%, which has superseded the efficiency of Gräztel dye-sensitized solar cell (DSSC) technology. Even with their exceptional optical and electric properties, lead halide perovskites suffer from poor stability. They degrade when exposed to moisture, heat, and UV radiation, which has hindered their commercialization. Moreover, halide perovskite materials consist of lead, which is toxic. Thus, exposure to these materials leads to detrimental effects on human health. Halide double perovskites with A2B′B″X6 (A = Cs, MA; B′ = Bi, Sb; B″ = Cu, Ag, and X = Cl, Br, I) have been investigated as potential replacements of lead halide perovskites. This work focuses on providing a detailed review of the structural, optical, and stability properties of these proposed perovskites as well as their viability to replace lead halide perovskites. The triumphs and challenges of the proposed lead-free A2B′B″X6 double perovskites are discussed here in detail.

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