Stable and Strong Emission CsPbBr<sub>3</sub> Quantum Dots by Surface Engineering for High-Performance Optoelectronic Films

Zheng, Chao; Bi, Chenghao; Huang, Fan; Binks, David J.; Tian, Jianjun

doi:10.1021/acsami.9b07818

Cited by 103 publications

(84 citation statements)

References 26 publications

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“…Each of the transients is well fitted by a triexponential function, and the resulting parameters are listed in Table T1 (Supporting Information). A slower relaxation rate indicates decreased density of the traps that are responsible for nonradiative pathways, [30, 32, 39] which is also consistent with the PLQY values (see Table T2 in Supporting Information).…”

Section: Resultssupporting

confidence: 82%

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals

Akhil

Dutt

Mishra

2020

Chemistry A European J

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Cesium lead halide perovskite nanocrystals (NCs) CsPbX3 (X=Cl, Br, and I) have been prominent materials in the last few years due to their high photoluminescence quantum yield (PLQY) for light‐emitting diodes and other significant applications in photovoltaics and optoelectronics. In colloidal CsPbX3 synthesis, the most commonly used ligands are oleic acid and oleylamine. The latter plays an important role in surface passivation but may also be responsible for poor colloidal stability as a result of facile proton exchange leading to the formation of labile oleylammonium halide, which pulls halide ions out of the NC surface. Herein, a facile, efficient, completely amine‐free synthesis of cesium lead bromide perovskite nanocrystals using hydrobromic acid as halide source and tri‐n‐octylphosphane as ligand under open‐atmospheric conditions is demonstrated. Hydrobromic acid serves as labile source of bromide ion, and thus this three‐precursor approach (separate precursors for Cs, Pb, Br) gives more control than a conventional single‐source precursor for Pb and Br (PbBr2). The use of HBr paved the way to eliminate oleylamine, and thus the formation of labile oleylammonium halide can be completely excluded. Various Cs:Pb:Br molar ratios were studied and optimum conditions for making very stable CsPbBr3 NCs with high PLQY were found. These completely amine‐free CsPbBr3 perovskite NCs synthesized under bromine‐rich conditions exhibit good stability and durability for more than three months in the form of colloidal solutions and films, respectively. Furthermore, stable tunable emission across a wide spectral range through anion exchange was demonstrated. More importantly, this work reports open‐atmosphere‐stable CsPbBr3 NCs films exhibiting strong PL, which can be further used for optoelectronic device applications.

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Section: Resultssupporting

confidence: 82%

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals

Akhil

Dutt

Mishra

2020

Chemistry A European J

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“…In addition, it is worth noting that because of perovskite NCs/QDs inherently high sensitivity to various environmental species such as light, thermophilic temperature, and humidity, [ 159–161 ] as well as the obvious problems of aggregation and phase transition, which makes them less stable under X‐ray irradiation. Therefore, the solution of these problems requires a reasonable design principle.…”

Section: Scintillator Materialsmentioning

confidence: 99%

Halide Perovskite, a Potential Scintillator for X‐Ray Detection

et al. 2020

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the coincidence efficiency. This indicates that the solid angle controlled by the PET system and the efficiency of the intrinsic detector are greater. [11,12] More significantly, the Compton events in the pulse height spectrum are mainly caused by scattering in the scintillator. Therefore, these deficiencies can be avoided by lowering the threshold. However, the signal provided by Compton scattering quanta in adjacent crystals may be higher than the threshold, and thus may affect the position resolution and make it worse. In X-ray computed tomography (CT), the body is mainly irradiated continuously from multiple directions by fan-shaped X-rays, while attenuation profiles are recorded, and finally reconstructed from the cross-sectional view of the body. [13] This technology mainly uses complex scanning methods in the field of clinical practice. At present, the realized way of X-rays detector can be roughly divided into two types, direct and indirect. The former one directly absorbs incident X-rays, generates electronic signals through semiconductors or engenders chemical signals through thin films. [14-17] This method can directly convert X-rays into visible light without going through other processes. Therefore, an X-ray detector with a wide linear response range, fast pulse rise time, high-energy resolution, and spatial resolution can be obtained, which makes it copiously applied in X-ray detection. [18-21] However, X-ray detectors based on semiconductors face the challenges of high cost and low efficiency. In addition, although the film is cheap, it is difficult to apply in digital form, which may limit its further development. The latter one refers to the conversion of X-rays (in the highenergy radiation, in addition to X-rays, α, β, and γ rays are also included) into ultraviolet visible (UV) light through scintillators which can be further captured by optical devices. [22-24] It consists of a scintillator and an array photodiode (PD). In contrast, since the scintillator that converts X-rays indirectly is cheap, it is easier to implement in the industry than direct detectors, and has the characteristics of low cost and abundant options, stability, and flexible conversion rate. [25,26] At present, indirect X-ray detectors are widely used in ordinary flat panel X-ray detectors. Moreover, it can be flexibly combined with commercially mature sensor arrays (e.g., amorphous silicon PDs, thin film transistor arrays, photomultiplier tubes, complementary metal oxide semiconductors, silicon avalanche PDs, and X-ray imaging charge-coupled devices [CCD]), therefore, they have attracted more attention. Scintillator is a unique class of luminescent materials, which is extensively used in many fields such as nondestructive testing, medical imaging, space probes, etc. Compared with the disadvantages of traditional scintillator materials which have high cost, are fragile, have long response time and low spatial resolution disadvantages, metal halide perovskites are considered to be the most potential scintillator materials in ...

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“…By using PbX 2 (X = I, Br, or Cl) as the passivation source, the device lifetime of PbS QD solar cells under ambient can be extended to over 1000 h. [168] When passivated with dodecyldimethylammonium bromide (DDAB), the Brion from DDAB can deactivate the Brvacancies on the CsPbBr 3 QD surface and increase the stability of QDs. [286] On the other hand, it is worth mentioning that passivation strategies for PbX and PVK QDs are very different due to the different ionic structures and surface energies. Besides halide species passivation, cadmium passivation, P-O-moieties passivation, and core/shell passivation are well-established strategies for improving the stability of PbX QDs.…”

Section: Strategies To Improve the Device Stabilitymentioning

confidence: 99%

Section: Stability Of Quantum Dot Photovoltaic Devicesmentioning

confidence: 99%

Quantum Dots for Photovoltaics: A Tale of Two Materials

Duan

Guan

et al. 2021

Advanced Energy Materials

104

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solar cells (PSCs), and colloidal quantum dots (QDs) solar cells, have been quickly developed. [3][4][5][6][7][8][9][10][11] Among these diverse PV materials, QDs possess unique nanostructural uniformity and highly tunable features, including quantum confinement effects and multiple exciton generation (MEG). [12][13][14][15][16][17] QD solar cells can be fabricated as semitransparent and flexible for promising applications, such as, wearable energy collectors and building-integrated photovoltaics. [18,19] QDs are defined as nanometer-sized semiconducting crystals, usually chemically synthesized with surface ligands. [20,21] When the size of a semiconducting crystal reduces to the molecular scale, its bulk properties alter simultaneously. [22,23] Owing to the quantum confinement effect, the absorption spectra and energy levels of QDs can be easily tuned by size variation. For example, the bandgap of cadmium telluride (CdTe) bulk material is around 1.48 eV, while the bandgap of the CdTe QD can be tuned from 2.06 to 2.32 eV by a slight size reduction from 2.47 to 2.10 nm. [24,25] The quantum confinement effect also allows better energy level and absorption matching for QD-based optoelectronic devices such as photodetectors, light-emitting diodes, and solar cells. [26][27][28][29][30][31][32][33][34] Additionally, QDs enable hot cattier extraction due to the MEG effect, where one absorbed photon with high energy may generate two or more excitons. [27,35,36] The unique capability of MEG in QD solar cells can potentially improve the power conversion efficiency (PCE) of single-junction devices and thus overcome the Shockley-Queisser (SQ) PCE limit. [37][38][39] In the past decades, increasing research attention has been paid to QD solar cells, and many materials have been exploited in this context. Although there have been some trials on leadfree materials, such as Indium arsenide (InAs), InP, and AgBiS 2 , their device performances are still poor, with PCE less than 6%. [40][41][42][43][44][45] Up to now, most of the high-performance devices were reported from lead-based QDs in two main categories: lead chalcogenides (PbX, X = S, Se) and lead halide perovskites (PVK). Figure 1a depicts the progress in PCE values and accumulated publication numbers of lead-based QD solar cells, shown as points and columns, respectively, since 2010. With recent progress in device structure design, band-alignment engineering, and optimized surface passivation, the PCE of QD solar cells has constantly increased, achieving a record of 16.6% to date. [46][47][48] Before 2016, QD solar cells were mainly composed of PbX (X = S, Se), and continuous efforts have recently culminated in a remarkable PCE of 13.8%. [53][54][55] PbX usually crystallizes in a cubic structure with S or Se atoms located at octahedral Quantum dot (QD) solar cells, benefiting from unique quantum confinement effects and multiple exciton generation, have attracted great research attention in the past decades. Before 2016, research efforts were mainly devoted to solar cells ...

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Stable and Strong Emission CsPbBr₃ Quantum Dots by Surface Engineering for High-Performance Optoelectronic Films

Abstract: Stable and strong emission CsPbBr3 quantum dots by surface engineering for high performance optoelectronic films. ACS Applied Materials and Interfaces .

Cited by 103 publications

References 26 publications

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals

Halide Perovskite, a Potential Scintillator for X‐Ray Detection

Quantum Dots for Photovoltaics: A Tale of Two Materials

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Stable and Strong Emission CsPbBr3 Quantum Dots by Surface Engineering for High-Performance Optoelectronic Films

Abstract: Stable and strong emission CsPbBr3 quantum dots by surface engineering for high performance optoelectronic films. ACS Applied Materials and Interfaces .

Cited by 103 publications

References 26 publications

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr3) Perovskite Nanocrystals

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr3) Perovskite Nanocrystals

Halide Perovskite, a Potential Scintillator for X‐Ray Detection

Quantum Dots for Photovoltaics: A Tale of Two Materials

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Product

Resources

About

Stable and Strong Emission CsPbBr₃ Quantum Dots by Surface Engineering for High-Performance Optoelectronic Films

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals