Optimizing Surface Chemistry of PbS Colloidal Quantum Dot for Highly Efficient and Stable Solar Cells via Chemical Binding

Hu, Long; Lei, Qi; Guan, Xinwei; Patterson, Robert; Yuan, Jianyu; Lin, Chun‐Ho; Kim, Jiyun; Geng, Xun; Younis, Adnan; Wu, Xianxin; Liu, Xinfeng; Wan, Tao; Chu, Dewei; Wu, Tom; Huang, Shujuan

doi:10.1002/advs.202003138

Cited by 54 publications

(44 citation statements)

References 65 publications

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“…A significantly suppressed spectra diffusion with an energy shift of only 13.9 meV is observed, indicating uniform morphology. [52] The suppressed energy funneling in the TBAI-PbS QD film implies the reduction of the tail states within the bandgap. [44] The strong electronic coupling between QDs introduced by the coordination strategy, causes a flattened energetic landscape and promotes the charge carrier transport in the QD matrix.…”

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confidence: 99%

Matrix Manipulation of Directly‐Synthesized PbS Quantum Dot Inks Enabled by Coordination Engineering

Liu

Shi

et al. 2021

Adv Funct Materials

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The direct-synthesis of conductive PbS quantum dot (QD) ink is facile, scalable, and low-cost, boosting the future commercialization of optoelectronics based on colloidal QDs. However, manipulating the QD matrix structures still is a challenge, which limits the corresponding QD solar cell performance. Here, for the first time a coordination-engineering strategy to finely adjust the matrix thickness around the QDs is presented, in which halogen salts are introduced into the reaction to convert the excessive insulating lead iodide into soluble iodoplumbate species. As a result, the obtained QD film exhibits shrunk insulating shells, leading to higher charge carrier transport and superior surface passivation compared to the control devices. A significantly improved power-conversion efficiency from 10.52% to 12.12% can be achieved after the matrix engineering. Therefore, the work shows high significance in promoting the practical application of directly synthesized PbS QD inks in large-area low-cost optoelectronic devices.

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confidence: 99%

Matrix Manipulation of Directly‐Synthesized PbS Quantum Dot Inks Enabled by Coordination Engineering

Liu

Shi

et al. 2021

Adv Funct Materials

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“…The polar (111) facet is Pb-rich, while the non-polar (100) facet has a stoichiometric Pb to X ratio. [252,253] After interacting with surface ligands for charge balance, (111) facets show higher resistivity to oxidation than (100) facets, as most of the surface sites on (111) facets can be well-passivated. [254] Compared to (100) facets, (111) facets have a denser ligand shell hindering oxidant diffusion.…”

Section: Degradation Mechanismsmentioning

confidence: 99%

“…[ 288 ] As a result, they demonstrated PbS QD solar cells exhibiting improved operational stability, which maintained over 80% of its initial PCE after operation at maximum power point (MPP) for 300 h. Using a similar approach, Huang and coworkers applied potassium triiodide (KI 3 ) combined with PbX 2 matrix as surface ligands on PbS QDs and demonstrated remarkable operational stability of QD solar cells. [ 253 ] After the continuous operation at MPP for 20 h, their fabricated device maintained 94% of its initial PCE of 12.1%. For PVK QDs, effective passivation is needed to eliminate the ionic surface degradation sources.…”

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

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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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“…5C). [79][80][81][82] This was found to improve airstability of PbS nanocrystals due to saturation of (100) surfaces [83] or complete surface passivation. [42] The method is now extended to pseudohalide (i.e.…”

Section: Solution-phase Ligand Exchangementioning

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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Optimizing Surface Chemistry of PbS Colloidal Quantum Dot for Highly Efficient and Stable Solar Cells via Chemical Binding

Cited by 54 publications

References 65 publications

Matrix Manipulation of Directly‐Synthesized PbS Quantum Dot Inks Enabled by Coordination Engineering

Matrix Manipulation of Directly‐Synthesized PbS Quantum Dot Inks Enabled by Coordination Engineering

Quantum Dots for Photovoltaics: A Tale of Two Materials

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

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