Metal Halide Perovskites: From Crystal Formations to Light‐Emitting‐Diode Applications

Kim, Young-Hoon; Kim, Sungjin; Jo, Seung Hyeon; Lee, Tae‐Woo

doi:10.1002/smtd.201800093

Cited by 37 publications

(28 citation statements)

References 193 publications

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“…Inorganic cesium lead halide (CsPbX 3 , X = Cl, Br, I) perovskite quantum dots (QDs) have attracted great attention in recent years due to their high photoluminescence quantum yield (PL QY) and high color purity . Their high defect tolerance provides bright PL that is free from passivation shells .…”

Section: Methodsmentioning

confidence: 99%

CsPbBr₃ Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification

et al. 2019

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bonds. [18,19] The formation of hydrogen bonds reduces the coulombic interactions between lead and bromide ions, and then ammonium ligands will fall off from the QD surface along with bromide ions (Scheme 1a left). [20] On the other hand, the deprotonated ammonium ligands cannot interact with the CsPbBr 3 QDs.Therefore, the use of a single ligand without amine groups and reversible processes could overcome the purification stability problem, as shown recently by Yassitepe et al, who developed an aminefree method using only oleic acid (OA) as ligands. [21] The resulting CsPbBr 3 QDs could be washed several times without size increase or emission shift (Scheme 1a middle); however, the QY of these QDs was relatively low and the long-term stability was poor. The low QY results from the presence of enormous surface bromide vacancies (V Br ), since V Br exhibited obvious negative exciton trapping effect (Scheme 1b middle). [22] The groups of both Xia and Alivisatos recently confirmed the effect of V Br in their very recent works and near 100% QY can be achieved swimmingly by compensating Br ions with any bromides during or after synthesis (Scheme 1b left). [23,24] Hence, it seems contradictory that considering the QY, surface V Br should be avoided, while on account of good stability, ammonium which interacts with Br atoms should be excluded. To reduce the V Br density and reversible protonation, Kovalenko et al. introduced several kinds of zwitterionic ligands. [15,25] CsPbBr 3 QDs maintained high QY values of ≈80% and exhibited good purification stability. However, the preparation procedures were complicated, and even required precursor synthesis. Tan et al. reported the preparation of highly luminescent and stable CsPbBr 3 QDs prepared with addition of octylphosphonic acid (OPA). [26] However, in addition to OPA, the preparation also required the introduction of OA and trioctylphosphine oxide (TOPO), complicating the mechanism because TOPO and OA can also passivate and efficiently stabilize the CsPbBr 3 surface. [27,28] Additionally, OPA is insoluble in octadecene and is unable to dissolve PbBr 2 without TOPO. [29] In this work, we propose a concept of equivalent ligand, hypothesizing that if a ligand can play a role similar to Br ions to a certain extent and form strong interaction with lead ions (surfactant), then the problems of V Br and weak interaction can be solved simultaneously. The simplest source of Br ions is HBr, andThe stability and optoelectronic device performance of perovskite quantum dots (Pe-QDs) are severely limited by present ligand strategies since these ligands exhibit a highly dynamic binding state, resulting in serious complications in QD purification and storage. Here, a "Br-equivalent" ligand strategy is developed in which the proposed strong ionic sulfonate heads, for example, benzenesulfonic acid, can firmly bind to the exposed Pb ions to form a steady binding state, and can also effectively eliminate the exciton trapping probability due to bromide vacancies. From these two aspects, the s...

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Section: Methodsmentioning

confidence: 99%

CsPbBr₃ Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification

et al. 2019

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“…They are not only strong light absorbers with excellent semiconducting properties for solar cells, but also promising light‐emitting materials with high PL efficiency, narrow and easily tunable emissive line shapes, and wide color gamut . Since the pioneering work on room‐temperature perovskite LEDs was reported in 2014, considerable progress has been made through elaborate materials and devices design as well as advanced processing techniques . As a consequence, a series of efficient perovskite LEDs has been obtained with EQEs approaching 20% .…”

Section: Characteristics Of Leds Based On In Situ Synthesized Fapbi3 mentioning

confidence: 99%

Efficient and Tunable Electroluminescence from In Situ Synthesized Perovskite Quantum Dots

Wang

Zhang

et al. 2019

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applications in optical and electronic devices, such as light-emitting diodes (LEDs), [2] solar cells, [3] quantum communications elements, [4] and thermoelectrics. [5] In general, semiconductor QDs can be obtained through epitaxial [5] or colloidal [2] growth, using vapor phase and chemical reactions, respectively. In contrast to the epitaxial QDs, colloidal QDs are solution-processable semiconductors. Such materials are compatible with light-weight and flexible plastic substrates and carry promise for future low-cost and large-area optoelectronic devices. [6] In particular, colloidal QDs have easily tunable emission, narrow emission bandwidth, and high photoluminescence (PL) efficiency, making them ideal candidates for LEDs. [7] Since the first demonstration in 1994, [8] colloidal QD LEDs have realized major advances, currently reaching external quantum efficiencies (EQEs) over 20%. [9,10] Recently, metal halide perovskites have emerged as promising solutionprocessable semiconductors, competitive with the best inorganic semiconductors such as silicon and gallium arsenide. [11] They are not only strong light absorbers with excellent semiconducting properties for solar cells, but also promising light-emitting materials with high PL efficiency, narrow and easily tunable emissive line shapes, and wide color gamut. [12] Since the pioneering work on room-temperature perovskite LEDs was reported in 2014, [13] Semiconductor quantum dots (QDs) are among the most promising nextgeneration optoelectronic materials. QDs are generally obtained through either epitaxial or colloidal growth and carry the promise for solutionprocessed high-performance optoelectronic devices such as light-emitting diodes (LEDs), solar cells, etc. Herein, a straightforward approach to synthesize perovskite QDs and demonstrate their applications in efficient LEDs is reported. The perovskite QDs with controllable crystal sizes and properties are in situ synthesized through one-step spin-coating from perovskite precursor solutions followed by thermal annealing. These perovskite QDs feature size-dependent quantum confinement effect (with readily tunable emissions) and radiative monomolecular recombination. Despite the substantial structural inhomogeneity, the in situ generated perovskite QDs films emit narrow-bandwidth emission and high color stability due to efficient energy transfer between nanostructures that sweeps away the unfavorable disorder effects. Based on these materials, efficient LEDs with external quantum efficiencies up to 11.0% are realized. ThisThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.201804947.One of the most attractive properties of semiconductor quantum dots (QDs) is a remarkable change of optical properties as a function of the crystal size. [1] In principle, their electronic transitions shift to higher energy with decreasing crystal dimensions, well known as the size-dependent quantum confinement effect. This property makes QDs attractive for the Small 20...

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“…Metal halide perovskites attract considerable attention due to their remarkable properties revealing potential applications in optoelectronic devices such as solar cells [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ], photodetectors [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], light emitting diodes [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. They have also been used for photocatalysts [ 35 ] and bioimaging [ 36 ].…”

Section: Introductionmentioning

confidence: 99%

Impact of Cesium Concentration on Optoelectronic Properties of Metal Halide Perovskites

et al. 2022

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Performance of a perovskite solar cell is largely influenced by the optoelectronic properties of metal halide perovskite films. Here we study the influence of cesium concentration on morphology, crystal structure, photoluminescence and optical properties of the triple cation perovskite film. Incorporation of small amount (x = 0.1) of cesium cations into Csx(MA0.17FA0.83)1-x Pb(I0.83Br0.17)3 leads to enhanced power conversion efficiency (PCE) of the solar cell resulting mainly from significant rise of the short-current density and the fill factor value. Further increase of Cs concentration (x > 0.1) decreases the film’s phase purity, carrier lifetime and correspondingly reduces PCE of the solar cell. Higher concentration of Cs (x ≥ 0.2) causes phase segregation of the perovskite alongside with formation of Cs-rich regions impeding light absorption.

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Metal Halide Perovskites: From Crystal Formations to Light‐Emitting‐Diode Applications

Cited by 37 publications

References 193 publications

CsPbBr₃ Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification

CsPbBr₃ Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification

Efficient and Tunable Electroluminescence from In Situ Synthesized Perovskite Quantum Dots

Impact of Cesium Concentration on Optoelectronic Properties of Metal Halide Perovskites

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Metal Halide Perovskites: From Crystal Formations to Light‐Emitting‐Diode Applications

Cited by 37 publications

References 193 publications

CsPbBr3 Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification

CsPbBr3 Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification

Efficient and Tunable Electroluminescence from In Situ Synthesized Perovskite Quantum Dots

Impact of Cesium Concentration on Optoelectronic Properties of Metal Halide Perovskites

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CsPbBr₃ Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification

CsPbBr₃ Quantum Dots 2.0: Benzenesulfonic Acid Equivalent Ligand Awakens Complete Purification