Stability enhancement of PbS quantum dots by site-selective surface passivation for near-infrared LED application

Zhang, Xinsu; Chen, Yujuan; Lian, Linyuan; Zhang, Zizhen; Liu, Yixuan; Song, Li; Zhang, Jianbing; Xu, Shu

doi:10.1007/s12274-020-3081-5

Cited by 41 publications

(22 citation statements)

References 57 publications

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“…Introduction PbS quantum dots (QDs) are promising candidates in various optoelectronic applications, such as lasers, 1,2 light-emitting diodes (LED), 3,4 photovoltaics, [5][6][7] and imagers. 8 The size-dependent optical gap allows to tune the target wavelength in a wide range, from 825 to 1750 nm.…”

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confidence: 99%

“…PbS quantum dots (QDs) are promising candidates in various optoelectronic applications, such as lasers, , light-emitting diodes (LED), , photovoltaics, − and imagers . The size-dependent optical gap allows to tune the target wavelength in a wide range, from 825 to 1750 nm. − The fabrication of these devices typically requires the synthesis of PbS QDs, followed by the evaporation of solvent to create a solid-state film composed of close-packed PbS QDs and finally the deposition of electrodes and charge transfer layers.…”

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confidence: 99%

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Size and Solvation Effects on Electronic and Optical Properties of PbS Quantum Dots

Sklénard

Mugny

Chehaibou

et al. 2022

J. Phys. Chem. Lett.

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PbS quantum dots (QDs), among the most mature nanocrystals obtained by colloidal chemistry, are promising candidates in optoelectronic applications at various operational frequencies. QD device performances are often determined by charge transport, either carrier injection before photoemission or charge detection after photoabsorption, which is significantly influenced by the dielectric environment. Here, we present the electronic structure and the optical gap of PbS QDs versus size for various solvents calculated using ab initio methods including the many-body perturbation approaches. This study highlights the importance of the dielectric environment, pointing out 1) the non-negligible shift of the electronic structure due to the ground state polarization; 2) a substantial impact on the electronic bandgap. The electron-hole binding energy, which varies largely with the QD size and solvent, is well-described by 1 an electrostatic model. This study reveals the fundamental physics of size and solvation effects, which could be useful to design PbS QDs-based optoelectronic devices.

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confidence: 99%

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confidence: 99%

Size and Solvation Effects on Electronic and Optical Properties of PbS Quantum Dots

Sklénard

Mugny

Chehaibou

et al. 2022

J. Phys. Chem. Lett.

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“…It has been reported that PbS quantum dots (≈4 nm in size) have dominant cationrich (111) surfaces and a few electrically neutral (100) surfaces. [2,43,44] The (100) surface of PbS QDs is known to be less densely pas sivated with ligands, allowing this facet to readily oxidize or fuse with other QDs. [45,46] As a result, the mild sintering effect between QDs accelerates fusion between the (100) surfaces, which eliminates the PbO binding site on the surface of QDs and increases PbS binding between QDs, consistent with the UV-vis spectra in Figure 2A and TEM images (Figure S5, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Suppressing the Dark Current in Quantum Dot Infrared Photodetectors by Controlling Carrier Statistics

Jung

Woo

Shin

et al. 2021

Advanced Optical Materials

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Lead sulfide colloidal quantum dot photodiodes (PbS QDPDs) exhibit a high energy conversion efficiency for infrared detection. Despite the high photoinduced current, the performance of PbS QDPDs is limited by the high dark current which is rarely investigated. Understanding the dark current in PbS QDPDs is critical to improving the detectivity of PbS QDPDs. Herein, it is demonstrated that minority carriers of I‐passivated PbS films and trap sites of EDT‐passivated PbS films are related to the dark current of PbS QDPD. Utilizing annealing and low‐temperature ligand exchange processes, the dark current density can be decreased almost tenfold by suppressing the minority carrier diffusion in the PN junction and trap‐assisted charge injection from the electrode. PN junction simulation, space charge limited current measurements, as well as structural, optical, and chemical characterizations are conducted to elucidate the origins of the dark current suppression. The authors achieve the lowest dark current density of 2.9 × 10−5 mA cm−2 at −1 V among PbS‐based QDPDs and a high detectivity of 6.7 × 1012 Jones at 980 nm. It is believed that this work provides fundamental understanding of carrier statistics in nanomaterials and device performance as well as a technological basis for realizing low‐cost high‐performance optoelectronic devices.

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“…To achieve high photoluminescent quantum yields, PbS nanocrystals are typically covered with a thin CdS shell [153,154] or the nanocrystal surface is site-selectively passivated using trioctylphosphine. [155] Similarly to PbS solar cells, for the PbS nanocrystal LEDs, we see the importance and impact of surfaces and the immediate environment of the nanocrystals. For example, recent work has shown how the NC surface impacts electronphonon coupling strength and linewidth and recombination dynamics.…”

Section: Packing and Ordering Of Nanocrystals Within Thin Filmsmentioning

confidence: 99%

Nanocrystal Quantum Dot Devices: How the Lead Sulfide (PbS) System Teaches Us the Importance of Surfaces

Lin

Yarema

Liu

et al. 2021

Chimia

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Semiconducting thin films made from nanocrystals hold potential as composite hybrid materials with new functionalities. With nanocrystal syntheses, composition can be controlled at the sub-nanometer level, and, by tuning size, shape, and surface termination of the nanocrystals as well as their packing, it is possible to select the electronic, phononic, and photonic properties of the resulting thin films. While the ability to tune the properties of a semiconductor from the atomistic- to macro-scale using solution-based techniques presents unique opportunities, it also introduces challenges for process control and reproducibility. In this review, we use the example of well-studied lead sulfide (PbS) nanocrystals and describe the key advances in nanocrystal synthesis and thin-film fabrication that have enabled improvement in performance of photovoltaic devices. While research moves forward with novel nanocrystal materials, it is important to consider what decades of work on PbS nanocrystals has taught us and how we can apply these learnings to realize the full potential of nanocrystal solids as highly flexible materials systems for functional semiconductor thin-film devices. One key lesson is the importance of controlling and manipulating surfaces.

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Stability enhancement of PbS quantum dots by site-selective surface passivation for near-infrared LED application

Cited by 41 publications

References 57 publications

Size and Solvation Effects on Electronic and Optical Properties of PbS Quantum Dots

Size and Solvation Effects on Electronic and Optical Properties of PbS Quantum Dots

Suppressing the Dark Current in Quantum Dot Infrared Photodetectors by Controlling Carrier Statistics

Nanocrystal Quantum Dot Devices: How the Lead Sulfide (PbS) System Teaches Us the Importance of Surfaces

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