Photo de-mixing in mixed halide perovskites: the roles of ions and electrons

Abstract Mixed halide perovskites have attracted great interest for applications in solar cells, light emitting diodes and other optoelectronic devices due to their tunability of optical properties. However, these mixtures tend to undergo de-mixing into separate phases when exposed to light, which compromises their operational reliability in devices (photo de-mixing). Several models have been proposed to elucidate the origin of the photo de-mixing process, including the contribution of strain, electronic carrier stabilization due to composition dependent electronic energies, and light induced ionic defect formation. In this perspective we discuss these hypotheses and focus on the importance of investigating defect chemical and ion transport aspects in these systems. We discuss possible optoionic effects that can contribute to the driving force of de-mixing and should therefore be considered in the overall energy balance of the process. These effects include the selective self-trapping of photo-generated holes as well as scenarios involving multiple defects. This perspective provides new insights into the origin of photo de-mixing from a defect chemistry point of view, raising open questions and opportunities related to the phase behavior of mixed halide perovskites.

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Photostable and Uniform CH3NH3PbI3 Perovskite Film Prepared via Stoichiometric Modification and Solvent Engineering

Nanomaterials ◽

10.3390/nano11020405 ◽

2021 ◽

Vol 11 (2) ◽

pp. 405

Author(s):

Daocheng Hong ◽

Mingyi Xie ◽

Yuxi Tian

Keyword(s):

Solar Cells ◽

Optoelectronic Devices ◽

Solvent Engineering ◽

Light Emitting ◽

Light Emitting Devices ◽

Coverage Ratio ◽

Fabrication Procedure ◽

Fabrication Condition ◽

Halide Perovskites ◽

Photoluminescence Efficiency

Solution-processed organometal halide perovskites (OMHPs) have been widely used in optoelectronic devices, and have exhibited brilliant performance. One of their generally recognized advantages is their easy fabrication procedure. However, such a procedure also brings uncertainty about the opto-electric properties of the final samples and devices, including morphology, stability, coverage ratio, and defect concentration. Normally, one needs to find a balanced condition, because there is a competitive relation between these parameters. In this work, we fabricated CH3NH3PbI3 films by carefully changing the ratio of the PbI2 to CH3NH3I, and found that the stoichiometric and solvent engineering not only determined the photoluminescence efficiency and defects in the materials, but also affected the photostability, morphology, and coverage ratio. Combining solvent engineering and the substitution of PbI2 by Pb(Ac)2, we obtained an optimized fabrication condition, providing uniform CH3NH3PbI3 films with both high photoluminescence efficiency and high photostability under either I-rich or Pb-rich conditions. These results provide an optimized fabrication procedure for CH3NH3PbI3 and other OMHP films, which is crucial for the performance of perovskite-based solar cells and light emitting devices.

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Mixed Dimensional 0D/3D Perovskite Heterostructure for Efficient Green Light Emitting Diodes

Journal of Materials Chemistry C ◽

10.1039/d1tc03611d ◽

2021 ◽

Author(s):

Lyuchao Zhuang ◽

Lingling Zhai ◽

Yanyong Li ◽

Ren Hui ◽

Mingjie Li ◽

...

Keyword(s):

Light Emitting Diodes ◽

Optoelectronic Devices ◽

Green Light ◽

Metal Halide ◽

Next Generation ◽

Light Emitting ◽

Photoelectric Characteristics ◽

Halide Perovskites

Metal halide perovskites are emerging materials for next-generation optoelectronic devices, of which all-inorganic CsPbBr3 perovskite has attracted increasing attention due to outstanding stability and excellent photoelectric characteristics compared with organic-inorganic...

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Organic interfacial materials for perovskite-based optoelectronic devices

Energy & Environmental Science ◽

10.1039/c8ee02744g ◽

2019 ◽

Vol 12 (4) ◽

pp. 1177-1209 ◽

Cited By ~ 66

Author(s):

Hong Duc Pham ◽

Li Xianqiang ◽

Wenhui Li ◽

Sergei Manzhos ◽

Aung Ko Ko Kyaw ◽

...

Keyword(s):

Solar Cells ◽

Light Emitting Diodes ◽

Optoelectronic Devices ◽

Light Emitting ◽

Development And Utilization ◽

Halide Perovskites

We summarize the development and utilization of organic interfacial materials in solar cells, photodetectors and light-emitting diodes based on organic–inorganic halide perovskites.

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Effect of the chemical composition on the structural, thermodynamical and mechanical properties of all-inorganic Halide Perovskites

Inorganic Chemistry Frontiers ◽

10.1039/d1qi00347j ◽

2021 ◽

Author(s):

Pablo Sanchez-Palencia ◽

Gregorio García ◽

Perla Wahnon ◽

Pablo Palacios

Keyword(s):

Mechanical Properties ◽

Solar Cells ◽

Chemical Composition ◽

Optoelectronic Devices ◽

Inorganic Hybrid ◽

Light Emitting ◽

Light Emitting Devices ◽

Halide Perovskites

Organic-inorganic hybrid halide perovskites are widely used in optoelectronic devices such as solar cells and light emitting devices. Pursuing solutions to a key problem of instability in most used MAPbI3,...

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Probing the ionic defect landscape in halide perovskite solar cells

Nature Communications ◽

10.1038/s41467-020-19769-8 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Sebastian Reichert ◽

Qingzhi An ◽

Young-Won Woo ◽

Aron Walsh ◽

Yana Vaynzof ◽

...

Keyword(s):

Deep Level ◽

Critical Role ◽

Perovskite Solar Cells ◽

Open Circuit ◽

Characteristic Energy ◽

Open Questions ◽

Halide Perovskites ◽

Halide Perovskite ◽

Transient Spectroscopy ◽

Ionic Defect

AbstractPoint defects in metal halide perovskites play a critical role in determining their properties and optoelectronic performance; however, many open questions remain unanswered. In this work, we apply impedance spectroscopy and deep-level transient spectroscopy to characterize the ionic defect landscape in methylammonium lead triiodide (MAPbI3) perovskites in which defects were purposely introduced by fractionally changing the precursor stoichiometry. Our results highlight the profound influence of defects on the electronic landscape, exemplified by their impact on the device built-in potential, and consequently, the open-circuit voltage. Even low ion densities can have an impact on the electronic landscape when both cations and anions are considered as mobile. Moreover, we find that all measured ionic defects fulfil the Meyer–Neldel rule with a characteristic energy connected to the underlying ion hopping process. These findings support a general categorization of defects in halide perovskite compounds.

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Control of spontaneous emission rate in lead halide perovskite film on hyperbolic metamaterial

Journal of Physics Conference Series ◽

10.1088/1742-6596/2015/1/012153 ◽

2021 ◽

Vol 2015 (1) ◽

pp. 012153

Author(s):

Pavel Tonkaev ◽

Sergey Makarov

Keyword(s):

Radiative Recombination ◽

Emission Rate ◽

Optoelectronic Devices ◽

Spontaneous Emission Rate ◽

Hyperbolic Metamaterials ◽

Light Emitting ◽

Hyperbolic Metamaterial ◽

Light Emitting Devices ◽

Halide Perovskites ◽

Lead Halide

Abstract Hyperbolic metamaterials represent a class of nanophotonic architectures with the possibility of controlling density of optical states. Due to this property, hyperbolic metamaterials can be employed as meta-electrodes in optoelectronic devices. On the other hand, lead halide perovskites have several promising properties for application in light-emitting devices. Moreover, a perovskite film is easily deposited on a hyperbolic metamaterial surface. Here, we theoretically show how to accelerate radiative recombination in a perovskite film with a hyperbolic metamaterial. This effect can be applied in light-emitting devices, where radiative recombination is extremely important.

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The Role of Economic Evaluation in Dissemination and Implementation Research

10.1093/oso/9780190683214.003.0006 ◽

2017 ◽

Cited By ~ 2

Author(s):

Ramesh Raghavan

Keyword(s):

Service Providers ◽

Implementation Strategies ◽

Cost Effective ◽

Point Of View ◽

Dissemination And Implementation ◽

Economic Point ◽

Open Questions ◽

Public Health Organizations ◽

Quality Health ◽

Dissemination And Implementation Research

This chapter presents an overview of how D&I research can be evaluated from an economic point of view. Dissemination and implementation imposes costs upon knowledge purveyors, provider organizations, public health organizations, and payers (including governments). However, whether these added costs will result in improved service delivery and, perhaps more importantly, client outcomes and improvements in population health remain as open questions. If emerging studies reveal that defined implementation strategies are more cost effective than “usual” implementation, then policymakers and service providers will need to resource these added costs of implementation in order to assure the success and sustainability of high-quality health services over the long term.

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Encapsulated Passivation of Perovskite Quantum Dot (CsPbBr3) Using a Hot-Melt Adhesive (EVA-TPR) for Enhanced Optical Stability and Efficiency

Crystals ◽

10.3390/cryst11040419 ◽

2021 ◽

Vol 11 (4) ◽

pp. 419

Author(s):

Saradh Prasad ◽

Mamduh J. Aljaafreh ◽

Mohamad S. AlSalhi ◽

Abeer Alshammari

Keyword(s):

Quantum Dots ◽

Band Gap ◽

Surface Defects ◽

Optoelectronic Devices ◽

Ethylene Vinyl Acetate ◽

Light Emitting ◽

Optical Stability ◽

Perovskite Quantum Dots ◽

Polymer Light Emitting Diodes ◽

Hot Melt

The notable photophysical characteristics of perovskite quantum dots (PQDs) (CsPbBr3) are suitable for optoelectronic devices. However, the performance of PQDs is unstable because of their surface defects. One way to address the instability is to passivate PQDs using different organic (polymers, oligomers, and dendrimers) or inorganic (ZnS, PbS) materials. In this study, we performed steady-state spectroscopic investigations to measure the photoluminescence (PL), absorption (A), transmission (T), and reflectance (R) of perovskite quantum dots (CsPbBr3) and ethylene vinyl acetate/terpene phenol (1%) (EVA-TPR (1%), or EVA) copolymer/perovskite composites in thin films with a thickness of 352 ± 5 nm. EVA is highly transparent because of its large band gap; furthermore, it is inexpensive and easy to process. However, the compatibility between PQDs and EVA should be established; therefore, a series of analyses was performed to compute parameters, such as the band gap, the coefficients of absorbance and extinction, the index of refractivity, and the dielectric constant (real and imaginary parts), from the data obtained from the above investigation. Finally, the optical conductivities of the films were studied. All these analyses showed that the EVA/PQDs were more efficient and stable both physically and optically. Hence, EVA/PQDs could become copolymer/perovskite active materials suitable for optoelectronic devices, such as solar cells and perovskite/polymer light-emitting diodes (PPLEDs).

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Recent Advances and Challenges in Halide Perovskite Crystals in Optoelectronic Devices from Solar Cells to Other Applications

Crystals ◽

10.3390/cryst11010039 ◽

2020 ◽

Vol 11 (1) ◽

pp. 39

Author(s):

Seunghyun Rhee ◽

Kunsik An ◽

Kyung-Tae Kang

Keyword(s):

Solar Cells ◽

Optoelectronic Devices ◽

Charge Carrier Mobility ◽

Light Emitting ◽

Fundamental Properties ◽

Perovskite Materials ◽

Hybrid Perovskite ◽

Band Position ◽

Different Characteristics ◽

High Charge Carrier Mobility

Organic-inorganic hybrid perovskite materials have attracted tremendous attention as a key material in various optoelectronic devices. Distinctive optoelectronic properties, such as a tunable energy band position, long carrier diffusion lengths, and high charge carrier mobility, have allowed rapid progress in various perovskite-based optoelectronic devices (solar cells, photodetectors, light emitting diodes (LEDs), and lasers). Interestingly, the developments of each field are based on different characteristics of perovskite materials which are suitable for their own applications. In this review, we provide the fundamental properties of perovskite materials and categorize the usages in various optoelectronic applications. In addition, the prerequisite factors for those applications are suggested to understand the recent progress of perovskite-based optoelectronic devices and the challenges that need to be solved for commercialization.

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