Highly efficient carrier multiplication in PbS nanosheets

Aerts, Michiel; Bielewicz, Thomas; Klinke, Christian; Grozema, Ferdinand C.; Houtepen, Arjan J.; Schins, Juleon M.; Siebbeles, Laurens D. A.

doi:10.1038/ncomms4789

Cited by 122 publications

(168 citation statements)

References 29 publications

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“…TA has been successfully applied for studying a high carrier multiplication (CM) efficiency in 2D PbS nanosheets [17]. CM is a process where the photoexcitation by a single high-energy photon creates multiple electron-hole pairs potentially useful for increasing solar cell efficiencies.…”

Section: Transient Absorption (Ta)mentioning

confidence: 99%

Ultrafast Transient Absorption and Terahertz Spectroscopy as Tools to Probe Photoexcited States and Dynamics in Colloidal 2D Nanostructures

Lauth

Kinge

Siebbeles

2016

Zeitschrift Für Physikalische Chemie

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Two-dimensional (2D) semiconductors hold high potential for the implementation of efficient ultrathin electronics (e.g. field-effect transistors, light emitting diodes and solar cell devices). In recent years, colloidal methods to synthesize ultrathin 2D materials have been developed that offer alternatives (like the production of non-layered 2D materials and upscaling) to mechanical exfoliation methods. By focusing on optoelectronic applications, it is important to characterize the nature and dynamics of photoexcited states in these materials. In this paper, we use ultrafast transient absorption (TA) and terahertz (THz) spectroscopy as optimal tools for such a characterization. We choose recently synthesized ultrathin colloidal 2D InSe nanosheets (inorganic layer thickness 0.8-1.7 nm; ≤ 5 nm including ligands) for discussing TA and THz spectroscopic studies and elucidate their charge carrier dynamics under photoexcitation with TA. THz spectroscopy is then used to extract contactless AC mobilities as high as 20 ± 2 cm 2 /Vs in single InSe layers. The obtained results underpin the general applicability of TA and THz spectroscopy for characterizing photoexcited states in 2D semiconductors.

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Section: Transient Absorption (Ta)mentioning

confidence: 99%

Ultrafast Transient Absorption and Terahertz Spectroscopy as Tools to Probe Photoexcited States and Dynamics in Colloidal 2D Nanostructures

Lauth

Kinge

Siebbeles

2016

Zeitschrift Für Physikalische Chemie

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“…10 An efficiency of 130% for the generation of an e-h pair by an absorbed photon has been reported for bulk silicon irradiated with ultraviolet light. 8 CM was found to be considerably enhanced in spatially confined materials, such as graphene 11 and lead sulfide nanosheets 12 (two-dimensional confinement), carbon nanotubes 13 and lead selenide nanorods 14,15 (one-dimensional confinement) and in quantum dots (zero-dimensional confinement). 16 In the latter case, CM was studied for quantum dots in a colloidal dispersion or embedded in a solid matrix.…”

Section: Introductionmentioning

confidence: 99%

Carrier multiplication in germanium nanocrystals

et al. 2015

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Carrier multiplication is demonstrated in a solid-state dispersion of germanium nanocrystals in a silicon-dioxide matrix. This is performed by comparing ultrafast photo-induced absorption transients at different pump photon energies below and above the threshold energy for this process. The average germanium nanocrystal size is approximately 5-6 nm, as inferred from photoluminescence and Raman spectra. A carrier multiplication efficiency of approximately 190% is measured for photo-excitation at 2.8 times the optical bandgap of germanium nanocrystals, deduced from their photoluminescence spectra.

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“…In addition to QDs and nanorods, there is recent evidence for MEG occurring in two-dimensional nanosheets [121]. While it has been shown that these nanostructures convert the photon energy in excess of MEG th E very efficiently into additional charge carriers, these twodimensional nanosheets require high photon energies to unlock MEG MEG th…”

Section: Tuning the Shape Of The Qdmentioning

confidence: 99%

Multiple exciton generation in quantum dot-based solar cells

et al. 2017

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Multiple exciton generation (MEG) in quantumconfined semiconductors is the process by which multiple bound charge-carrier pairs are generated after absorption of a single high-energy photon. Such charge-carrier multiplication effects have been highlighted as particularly beneficial for solar cells where they have the potential to increase the photocurrent significantly. Indeed, recent research efforts have proved that more than one chargecarrier pair per incident solar photon can be extracted in photovoltaic devices incorporating quantum-confined semiconductors. While these proof-of-concept applications underline the potential of MEG in solar cells, the impact of the carrier multiplication effect on the device performance remains rather low. This review covers recent advancements in the understanding and application of MEG as a photocurrent-enhancing mechanism in quantum dot-based photovoltaics.

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Highly efficient carrier multiplication in PbS nanosheets

Cited by 122 publications

References 29 publications

Ultrafast Transient Absorption and Terahertz Spectroscopy as Tools to Probe Photoexcited States and Dynamics in Colloidal 2D Nanostructures

Ultrafast Transient Absorption and Terahertz Spectroscopy as Tools to Probe Photoexcited States and Dynamics in Colloidal 2D Nanostructures

Carrier multiplication in germanium nanocrystals

Multiple exciton generation in quantum dot-based solar cells

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