PbS Colloidal Quantum Dots Infrared Solar Cells: Defect Information and Passivation Strategies

Khalaf, Gomaa Mohamed Gomaa; Li, Mingyu; Yan, Jun; Zhao, Xinzhao; Ma, Tianjun; Hsu, Hsien-Yi; Song, Haisheng

doi:10.1002/smsc.202300062

Cited by 12 publications

(3 citation statements)

References 129 publications

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“…20 However, the band gap shrinkage of larger PbS QDs (E g < 1 eV) may cause the downshift of conduction band levels, resulting in the undesired energy level arrangement and the impeditive electron transportation. 21 Thus, the energy band behaviors of the ETL should be adjusted accordingly. In addition, the trap states in ZnO ETL may become the trap centers of photogenerated electrons, resulting in the reduction of the extractable electrons concentration.…”

Section: Resultsmentioning

confidence: 99%

“…For traditional PbS QD ( E g > 1.3 eV) solar cells, the traditional ZnO ETL shows ideally matched energy levels . However, the band gap shrinkage of larger PbS QDs ( E g < 1 eV) may cause the downshift of conduction band levels, resulting in the undesired energy level arrangement and the impeditive electron transportation . Thus, the energy band behaviors of the ETL should be adjusted accordingly.…”

Section: Results and Discussionmentioning

confidence: 99%

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Effective Charge Collection of Electron Transport Layers for High-Performance Quantum Dot Infrared Solar Cells

Wang,

Liu,

Wei

et al. 2024

ACS Appl. Mater. Interfaces

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Infrared (IR) solar cells, capable of converting lowenergy IR photons to electron−hole pairs, are promising optoelectronic devices by broadening the utilization range of the solar spectrum to the short-wavelength IR region. The emerging PbS colloidal quantum dot (QD) IR solar cells attract much attention due to their tunable band gaps in the IR region, potential multiple exciton generation, and facile solution processing. In PbS QD solar cells, ZnO is commonly utilized as an electron transport layer (ETL) to establish a depleted heterostructure with a QD photoactive layer. However, band gap shrinkage of large PbS QDs makes it necessary to tailor the behaviors of the ZnO ETL for efficient carrier extraction in the devices. Herein, the characteristics of ZnO ETL are efficiently and flexibly tailored to match the QD layer by handily adjusting the postannealing process of ZnO ETL. With a suitable temperature, the well-matched energy level alignment and suppressed trap states are simultaneously achieved in the ZnO ETL, effectively reducing the nonradiative recombination and accelerating the electron injection from the QD layer to ETL. As a consequence, a high-performance PbS QD photovoltaic device with power conversion efficiencies (PCEs) of 10.09% and 1.37% is obtained under AM 1.5 and 1100 nm filtered solar illumination, demonstrating a simple and effective approach for achieving high-performance IR photoelectric devices.

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Section: Resultsmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Effective Charge Collection of Electron Transport Layers for High-Performance Quantum Dot Infrared Solar Cells

Wang,

Liu,

Wei

et al. 2024

ACS Appl. Mater. Interfaces

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“…8 Thus, much research focus is currently on the surface passivation of QDs in the PbS based IR solar cells. 9,10 However, the n-type electron transport layer (ETL), used for constructing depletion heterojunctions with the p-type QD photoactive layer, plays an equally important role to the other functional layers in the QD IRSCs. 11,12 Especially, charge extraction loss in heterojunction devices is more inclined to occur at the interfaces like the ETL/photoactive layer or the photoactive layer/hole transport layer.…”

mentioning

confidence: 99%

Suppressing Charge Extraction Loss in Quantum Dot Infrared Photovoltaics by Optimizing the Charge Transport Layer

Liu,

Wang,

Luo

et al. 2024

J. Phys. Chem. Lett.

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Infrared solar cells (IRSCs), capable of converting low-energy infrared photons to electron–hole pairs, are promising infrared optoelectronic devices because of their extended utilization region of the solar to short-wavelength infrared region. For PbS QDs IRSCs, charge extraction loss, easily generated at the interfaces, has been one of the dominate obstacles impeding the improvement of device efficiencies due to too many trap states and mismatched energy levels between the photoactive layer and electron transport layer (ETL). Herein, an advanced ZnO ETL was developed to improve the extraction of photogenerated charges from the PbS QD photoactive layer to ETLs. The advanced ETL film exhibited effectively suppressed trap states and better-matched energy levels compared with the QD layer. As a consequence, high-performance PbS QD IRSCs with the highest infrared power conversion efficiencies of 1.26% under 1100 nm filtered solar illumination are achieved, suggesting an effective and facile route for enhancing the charge extraction in infrared photovoltaics.

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Implementing Lattice and Energy Level Matching to Optimize Buried Interfaces for High‐Performance Perovskite Solar Cells

Sun,

Zhang,

et al. 2024

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In n‐i‐p type perovskite solar cells (PSCs), mismatches in energy level and lattice at the buried interface is highly detrimental to device performance. Here, thin PbS interconnect layer in situ coating on the SnO2 surface is grown. The function of PbS at the interface is different from the commonly used function of crystalline seeds in perovskite bulk. The theoretical calculation show that it helps construct an interconnect structure of SnO2/PbS/Perovskite with matched energy level and lattice. This not only increases conductivity of SnO2, but also upshifts Fermi energy levels (EF) of both SnO2 and buried perovskite due to charge transfer and perovskite's internal defect changes. Such a suitable energy level arrangement ensures a better energy level match at the interface, favoring efficient charge transfer and less open circuit voltage (Voc) loss. Additionally, in situ PL reveals that the template effect of PbS enable perovskite grain to grow bottom‐up because of their highly matched lattice parameters. This growth mode optimizes buried interface contact and crystallinity of perovskite. Ultimately, after PbS modification, a remarkable power conversion efficiency (PCE) exceeding 24% and better device stability are obtained. This work demonstrates an effective interconnect layers strategy to realize ideal interface contact toward high‐performance PSCs.

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PbS Colloidal Quantum Dots Infrared Solar Cells: Defect Information and Passivation Strategies

Cited by 12 publications

References 129 publications

Effective Charge Collection of Electron Transport Layers for High-Performance Quantum Dot Infrared Solar Cells

Effective Charge Collection of Electron Transport Layers for High-Performance Quantum Dot Infrared Solar Cells

Suppressing Charge Extraction Loss in Quantum Dot Infrared Photovoltaics by Optimizing the Charge Transport Layer

Implementing Lattice and Energy Level Matching to Optimize Buried Interfaces for High‐Performance Perovskite Solar Cells

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