Synergistic Surface Passivation of CH3NH3PbBr3 Perovskite Quantum Dots with Phosphonic Acid and (3‐Aminopropyl)triethoxysilane

Xu, Ke; Vickers, Evan T.; Rao, Longshi; Lindley, Sarah A.; Allen, A’Lester C.; Luo, Binbin; Li, Xueming; Zhang, Jin Z.

doi:10.1002/chem.201805656

Cited by 48 publications

(32 citation statements)

References 70 publications

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“…FTIR spectra were measured to understand the state of the surface ligands in CH 3 NH 3 PbBr 3 PQDs and PMSCs. As shown in Figure 5, for OcAm PMSCs, the characteristic bands at 2855 and 2923 cm −1 are assigned to symmetric and asymmetric CH 2 stretching modes, 61,64 and the band at 1465 cm −1 can be assigned to CH 2 bending vibration. The NH 2 bending at around 1600 cm −1 shifts to 1577 cm −1 upon coordination to metals, indicating the presence of OcAm on the PMSC surface.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH₃NH₃PbBr₃ Perovskite: Implications for Photonics and Energy Conversion

Liu

Vickers

et al. 2020

ACS Appl. Nano Mater.

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Metal halide perovskites, such as methylammonium lead halide (CH 3 NH 3 PbBr 3 ), have recently attracted tremendous attention due to their outstanding properties and promising applications. Here, CH 3 NH 3 PbBr 3 perovskite magic-sized clusters (PMSCs) and perovskite quantum dots (PQDs) are synthesized by surface passivation with various organic acids and amines through a ligand-assisted reprecipitation process (LARP). Their optical properties are investigated with ultraviolet−visible (UV−vis) absorption and photoluminescence (PL) spectroscopy. The structures and optical properties of the PMSCs and PQDs can be controlled by varying the ligand/precursor ratio and type as well as the concentration of ligands. Specifically, a high ligand/precursor ratio and excessive amines favor PMSCs, whereas excessive acids lead to the generation of PQDs over PMSCs. As a result, we can tune between PQDs and PMSCs by changing the amine/acid ligand ratio. Energy-dispersive X-ray (EDS) elemental mapping confirms the presence of the constituent elements of the perovskite, namely, Pb and Br. With the help of Fourier transform infrared (FTIR) results, a model is proposed to explain the mechanism of formation of both PQDs and PMSCs as well as their interconversion in terms of the ligands passivating the surface defect sites. This study provides important insights into the fundamental growth mechanisms of perovskite nanostructures, especially in terms of the interplay between the perovskite precursors and passivating ligands. The work has significant implications in applications of metal halide perovskites in photonics and energy conversion.

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Section: ■ Results and Discussionmentioning

confidence: 98%

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH₃NH₃PbBr₃ Perovskite: Implications for Photonics and Energy Conversion

Liu

Vickers

et al. 2020

ACS Appl. Nano Mater.

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“…14,138,332,352,357−365 For instance, in the case of CsPbI 3 , Cs + is considered as a weak acid, Pb 2+ a weak acid, as well, and I − a weak base, 366 while in the case of MAPbBr 3 , MA + is a weak acid and Br − is a weak base (though stronger than I − ). 360 Based on the Pearson acid/base case concept, weak acid defects require weak base ligands, while weak base defects require weak acid ligand for optimal passivation. 360 For example, short-chain organic PAs have stronger acidity, and thus their conjugate base has basicity stronger than that of their longer-chain counterparts.…”

Section: Surface Chemistry Of Colloidal Halide Perovskite Ncsmentioning

confidence: 99%

“…360 Based on the Pearson acid/base case concept, weak acid defects require weak base ligands, while weak base defects require weak acid ligand for optimal passivation. 360 For example, short-chain organic PAs have stronger acidity, and thus their conjugate base has basicity stronger than that of their longer-chain counterparts. 360 Four different linear alkyl PAs [PAs with the straight chain from short to long: MPA, nhexylphosphonic acid, 1-tetradecylphosphonic acid (TDPA), and n-octadecylphosphonic acid (ODPA)] have been used in conjunction with APTES as capping ligands to synthesize MAPbBr 3 perovskite NCs.…”

Section: Surface Chemistry Of Colloidal Halide Perovskite Ncsmentioning

confidence: 99%

“…360 For example, short-chain organic PAs have stronger acidity, and thus their conjugate base has basicity stronger than that of their longer-chain counterparts. 360 Four different linear alkyl PAs [PAs with the straight chain from short to long: MPA, nhexylphosphonic acid, 1-tetradecylphosphonic acid (TDPA), and n-octadecylphosphonic acid (ODPA)] have been used in conjunction with APTES as capping ligands to synthesize MAPbBr 3 perovskite NCs. 360 As illustrated in Figure 33a-ii, the protonated APTES and deprotonated PAs produce weak acidic R−NH 3 + , weak basic R−PO 2 (OH) − , and even weaker basic R−PO 3 2 .…”

Section: Surface Chemistry Of Colloidal Halide Perovskite Ncsmentioning

confidence: 99%

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State of the Art and Prospects for Halide Perovskite Nanocrystals

et al. 2021

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Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.

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“…Yu and coworkers reported the use of poly(ethylene oxide), while Xu and coworkers proved the use of phosphoric acids (PAs), to passivate the methylammonium lead bromide (MAPbBr 3 ) QDs. [289,290] Both methods are based on organic materials, which reduced the defects caused by the ionic bonding of PVK QDs and enhanced the device stability. Ling and coworkers introduced various inorganic sulphonium salts to passivate the CsPbI 3 QDs, and Zhang and coworkers used metal ion-based ligands to passivate the CsPbBr 3 QDs.…”

Section: Strategies To Improve the Device Stabilitymentioning

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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Synergistic Surface Passivation of CH₃NH₃PbBr₃ Perovskite Quantum Dots with Phosphonic Acid and (3‐Aminopropyl)triethoxysilane

Cited by 48 publications

References 70 publications

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH₃NH₃PbBr₃ Perovskite: Implications for Photonics and Energy Conversion

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH₃NH₃PbBr₃ Perovskite: Implications for Photonics and Energy Conversion

State of the Art and Prospects for Halide Perovskite Nanocrystals

Quantum Dots for Photovoltaics: A Tale of Two Materials

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Synergistic Surface Passivation of CH3NH3PbBr3 Perovskite Quantum Dots with Phosphonic Acid and (3‐Aminopropyl)triethoxysilane

Cited by 48 publications

References 70 publications

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH3NH3PbBr3 Perovskite: Implications for Photonics and Energy Conversion

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH3NH3PbBr3 Perovskite: Implications for Photonics and Energy Conversion

State of the Art and Prospects for Halide Perovskite Nanocrystals

Quantum Dots for Photovoltaics: A Tale of Two Materials

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Product

Resources

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Synergistic Surface Passivation of CH₃NH₃PbBr₃ Perovskite Quantum Dots with Phosphonic Acid and (3‐Aminopropyl)triethoxysilane

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH₃NH₃PbBr₃ Perovskite: Implications for Photonics and Energy Conversion

Varying the Concentration of Organic Acid and Amine Ligands Allows Tuning between Quantum Dots and Magic-Sized Clusters of CH₃NH₃PbBr₃ Perovskite: Implications for Photonics and Energy Conversion