A statistical exploration of multiple exciton generation in silicon quantum dots and optoelectronic application

Su, Wanli; Shen, Wen Zhong

doi:10.1063/1.3687184

Cited by 23 publications

(5 citation statements)

References 54 publications

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“…(2). 30 The constant 1.15 eV is the Eg value for bulk Si. 31 D −1 36 is the spatial localization of the electrons and holes, and D −1 indicates an increasing size dependent Coulomb attraction.…”

Section: Resultsmentioning

confidence: 99%

Improvement of Charge Transportation in Si Quantum Dot-Sensitized Solar Cells Using Vanadium Doped TiO<SUB>2</SUB>

Seo¹,

Ichida

Hashimoto

et al. 2016

j nanosci nanotechnol

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The multiple exciton generation characteristics of quantum dots have been expected to enhance the performance of photochemical solar cells. In previous work, we first introduced Si quantum dot for sensitized solar cells. The Si quantum dots were fabricated by multi-hollow discharge plasma chemical vapor deposition, and were characterized optically and morphologically. The Si quantum dot-sensitized solar cells had poor performance due to significant electron loss by charge recombination. Although the large Si particle size resulted in the exposure of a large TiO2 surface area, there was a limit to ho much the particle size could be decreased due to the reduced absorbance of small particles. Therefore, this work focused on decreasing the internal impedance to improve charge transfer. TiO2 was electronically modified by doping with vanadium, which can improve electron transfer in the TiO2 network, and which is stable in the redox electrolyte. Photogenerated electrons can more easily arrive at the conductive electrode due to the decreased internal impedance. The dark photovoltaic properties confirmed the reduction of charge recombination, and the photon-to-current conversion efficiency reflected the improved electron transfer. Impedance analysis confirmed a decrease in internal impedance and an increased electron lifetime. Consequently, these improvements by vanadium doping enhanced the overall performance of Si quantum dot-sensitized solar cells.

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Section: Resultsmentioning

confidence: 99%

Improvement of Charge Transportation in Si Quantum Dot-Sensitized Solar Cells Using Vanadium Doped TiO<SUB>2</SUB>

Seo¹,

Ichida

Hashimoto

et al. 2016

j nanosci nanotechnol

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show abstract

“…However, its inherent indirect band gap properties have limited its use in photovoltaic and light emitting diode applications. When the dimensions of Si nanoparticles (NPs) become comparable or smaller than Bohr radius of a bulk exciton ($4 nm for Si), [1][2][3][4] they undergo a remarkable transition from indirect to direct band gap semiconductor. 5 Under such conditions, band-to-band radiative recombination (rather than phonon-assisted indirect transitions) begins to dominate Si-NPs' luminescence properties.…”

Section: Introductionmentioning

confidence: 99%

Controlling luminescent silicon nanoparticle emission produced by nanosecond pulsed laser ablation: role of interface defect states and crystallinity phase

et al. 2016

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“…It has been shown that carrier multiplicationa process in which absorption of a single high-energy photon creates multiple electron–hole pairs (excitons)occurs efficiently in Si NCs. − This holds a great potential for highly efficient photovoltaic conversion exceeding the Shockley–Queisser limit . Carrier multiplication in Si NCs also has a potential for application in ultraviolet detectors . However, in a strong quantum confinement regime, electron–electron coupling is sufficiently enhanced in comparison to the electron–photon coupling.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigations and Modeling of Auger Recombination in Silicon Nanocrystals

2013

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The Auger process provides one of the most important nonradiative recombination channels in semiconductors and strongly enhances in nanostructures. In this paper, we investigate Auger recombination for silicon nanocrystals embedded in a SiO 2 matrix by transient-induced absorption. Past experience showed that such investigations are very difficult since, in contrast to nanocrystals of direct bandgap materials, exciton dynamics in silicon nanocrystals are dominated by efficient trapping and/or other fast nonradiative relaxation processes. Using a femtosecond pump−probe technique, we separate these processes and assign them to (i) very efficient nonradiative recombination in so-called "dark nanocrystals" and (ii) formation of a self-trapped excitonic state. Subsequently, we successfully measure the dynamics of Auger interaction between excitons and model this process in terms of exciton−exciton and 3-charge interaction. We find that the 3-charge interaction model provides a suitable framework to describe Auger recombination in silicon NCs.

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A statistical exploration of multiple exciton generation in silicon quantum dots and optoelectronic application

Cited by 23 publications

References 54 publications

Improvement of Charge Transportation in Si Quantum Dot-Sensitized Solar Cells Using Vanadium Doped TiO<SUB>2</SUB>

Improvement of Charge Transportation in Si Quantum Dot-Sensitized Solar Cells Using Vanadium Doped TiO<SUB>2</SUB>

Controlling luminescent silicon nanoparticle emission produced by nanosecond pulsed laser ablation: role of interface defect states and crystallinity phase

Experimental Investigations and Modeling of Auger Recombination in Silicon Nanocrystals

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