Design Strategy of Quantum Dot Thin‐Film Solar Cells

Kim, Taewan; Lim, Seonghye; Yun, Sunhee; Jeong, Sohee; Park, Jin Young; Choi, Jongmin

doi:10.1002/smll.202002460

Cited by 31 publications

(26 citation statements)

References 122 publications

(197 reference statements)

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“…As a result, colloidal QDs have attracted attention in various optoelectronic fields such as bio-imaging, displays, flexible devices, and stretchable devices 3 – 6 . Chalcogenide colloidal QDs such as PbS, CdSe have been successfully applied to many fields as their synthetic methods were extensively developed, providing a targeted wavelength with high size uniformity 7 – 11 . Meanwhile, colloidal synthesis of rather covalent colloidal QDs is lagging behind because of difficulties originating from limited control over precursor reactivity in solution 2 , 12 .…”

Section: Introductionmentioning

confidence: 99%

Diffusion dynamics controlled colloidal synthesis of highly monodisperse InAs nanocrystals

2021

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Highly monodisperse colloidal InAs quantum dots (QDs) with superior optoelectronic properties are promising candidates for various applications, including infrared photodetectors and photovoltaics. Recently, a synthetic process involving continuous injection has been introduced to synthesize uniformly sized InAs QDs. Still, synthetic efforts to increase the particle size of over 5 nm often suffer from growth suppression. Secondary nucleation or interparticle ripening during the growth accompanies the inhomogeneity in size as well. In this study, we propose a growth model for the continuous synthetic processing of colloidal InAs QDs based on molecular diffusion. The experimentally validated model demonstrates how precursor solution injection reduces monomer flux, limiting particle growth during synthesis. As predicted by our model, we control the diffusion dynamics by tuning reaction volume, precursor concentration, and injection rate of precursor. Through diffusion-dynamics-control in the continuous process, we synthesize the InAs QDs with a size over 9.0-nm (1Smax of 1600 nm) with a narrow size distribution (12.2%). Diffusion-dynamics-controlled synthesis presented in this study effectively manages the monomer flux and thus overcome monomer-reactivity-originating size limit of nanocrystal growth in solution.

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Section: Introductionmentioning

confidence: 99%

Diffusion dynamics controlled colloidal synthesis of highly monodisperse InAs nanocrystals

2021

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“…[146] Abundant previous researches have revealed that using shorter conductive ligand for ligand substitution via ligand exchange processes can significantly improve the performance of the relevant QD solar cells. [147,148] It should be noted that the removal of the long insulating ligands on the surface of QDs can create surface defects, phase transition, and degradation of the QD, where re-passivation of the QD surface is then needed. [149] During the past decade, considerable reports of ligand-exchange have greatly improved the efficiency of PbX QD solar cells.…”

Section: Surface Chemistrymentioning

confidence: 99%

“…a) Progress in the PCE and the accumulated publication numbers of lead‐based QD solar cells since 2010. [ 88–148 ] The data of the number of publications is taken from Scopus ( www.scopus.com). b) Schematic diagram of the material structure of PbX (X = S, Se) (Reproduced with permission.…”

Section: Introductionmentioning

confidence: 99%

Quantum Dots for Photovoltaics: A Tale of Two Materials

Duan

Guan

et al. 2021

Advanced Energy Materials

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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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Section: Introductionmentioning

confidence: 99%

“…[4] Especially colloidal indium phosphide (InP) quantum dots (QDs) have gained a lot of attention in the display industry and market, [5] as well as increasing number of research has been done for colloidal QD-based optoelectronic applications from light-emitting diodes and photovoltaics to lasers and photodetectors. [6][7][8] One challenge of colloidal semiconductors is their surface ligand, which is critical to control their crystal growth but causes poor charge transport in their solid state. Enhancing charge transport of QD solids is key to realize solid-state optoelectronic devices, and surface processing has been developed in a manner of the ligand exchange process using short-chain ligands such as thiol or halide ions.…”

Section: Introductionmentioning

confidence: 99%

Energetic Sulfide Vapor‐Processed Colloidal InAs Quantum Dot Solids for Efficient Charge Transport and Photoconduction

Koh

Choi

Kim

et al. 2021

Advanced Photonics Research

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The energetic sulfide vapor process on colloidal indium arsenide (InAs) quantum dots (QDs) for integrated optoelectronic devices is demonstrated. X‐ray photoemission spectroscopy supports the presence of sulfur on QD surface, which increases the air stability, and ultraviolet photoemission spectroscopy and field‐effect transistor analysis confirm n‐type charge transport of corresponding QD films with higher electron mobilities. Photoconductivity of the same devices in near‐infrared wavelength shows gate bias‐dependent recombination of photogenerated carriers, coming from charge accumulation and depletion transition of QD channels. The synergetic approach of the vapor process on colloidal QD solids opens a promising opportunity for scalable and complementary metal‐oxide semiconductor‐compatible optoelectronic devices.

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Design Strategy of Quantum Dot Thin‐Film Solar Cells

Cited by 31 publications

References 122 publications

Diffusion dynamics controlled colloidal synthesis of highly monodisperse InAs nanocrystals

Diffusion dynamics controlled colloidal synthesis of highly monodisperse InAs nanocrystals

Quantum Dots for Photovoltaics: A Tale of Two Materials

Energetic Sulfide Vapor‐Processed Colloidal InAs Quantum Dot Solids for Efficient Charge Transport and Photoconduction

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