Two-step photon up-conversion solar cells

Asahi, Shigeo; Teranishi, Haruyuki; Kusaki, Kazuki; Kaizu, Toshiyuki; Kita, Takashi

doi:10.1038/ncomms14962

Cited by 94 publications

(58 citation statements)

References 44 publications

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“…Plasmon‐mediated photoexcitation of hot carriers has attracted an increasing research interest due to its wide potential applications in photovoltaics, photodetection, and photocatalysis . Unlike photoexcited carriers in semiconductors, the hot carriers stimulated in metals exhibit favorable excitation conditions by overcoming the band‐gap limitation and can directly participant in chemical reactions through charge transfer .…”

Section: Introductionmentioning

confidence: 99%

Plasmonic Au/TiO₂‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction

Shang

Shi

et al. 2018

Adv Funct Materials

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Plasmon-induced hot carriers have vast potential for light-triggered highefficiency carrier generation and extraction, which can overcome the optical band gap limit of conventional semiconductor-based optoelectronic devices. Here, it is demonstrated that Au/TiO 2 dumbbell nanostructures assembled on a thin Au film serve as an efficient optical absorber and a hot-carrier generator in the visible region. Upon excitation of localized surface plasmons in such coupled particle-on-film nanocavities, the energetic conduction electrons in Au can be injected over the Au/TiO 2 Schottky barrier and migrated to TiO 2 , participating in the chemical reaction occurring at the TiO 2 surface. Compared with the same dumbbell nanostructures on an indium tin oxide (ITO) film, such nanocavities exhibit remarkable enhancement in both photocurrent amplitude and reaction rate that arise from increased light absorption and near-field amplification in the presence of the Au film. The incidentwavelength-dependent photocurrent and reaction rate measurements jointly reveal that Au-film-mediated near-field localization facilitates more efficient electron-hole separation and transport in the dumbbells and also promotes strong d-band optical transitions in the Au film for generation of extra hot electrons. Such nanocavities provide a new plasmonic platform for effective photoexcitation and extraction of hot carriers and also better understanding of their fundamental science and technological implications in solar energy harvesting.

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Section: Introductionmentioning

confidence: 99%

Plasmonic Au/TiO₂‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction

Shang

Shi

et al. 2018

Adv Funct Materials

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“…To this end, it is necessary that the IB is half-filled with electrons so that it can supply electrons to the CB as well as receive them from the VB. This two-photon absorption process is illustrated in Figure 2 and has been experimentally detected in IBSCs based on quantum dots [121]. The electron-hole pairs generated in this way add up to the conventionally generated ones by the absorption of a single photon (3), the third one, pumping an electron from the VB to the CB.…”

Section: Intermediate Band Solar Cellsmentioning

confidence: 85%

Multiscale in modelling and validation for solar photovoltaics

et al. 2018

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Photovoltaics is amongst the most important technologies for renewable energy sources, and plays a key role in the development of a society with a smaller environmental footprint. Key parameters for solar cells are their energy conversion efficiency, their operating lifetime, and the cost of the energy obtained from a photovoltaic system compared to other sources. The optimization of these aspects involves the exploitation of new materials and development of novel solar cell concepts and designs. Both theoretical modeling and characterization of such devices require a comprehensive view including all scales from the atomic to the macroscopic and industrial scale. The different length scales of the electronic and optical degrees of freedoms specifically lead to an intrinsic need for multiscale simulation, which is accentuated in many advanced photovoltaics concepts including nanostructured regions. Therefore, multiscale modeling has found particular interest in the photovoltaics community, as a tool to advance the field beyond its current limits. In this article, we review the field of multiscale techniques applied to photovoltaics, and we discuss opportunities and remaining challenges.

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“…Intermediate‐band solar cells (IB‐SCs) are of another type of the higher efficiency SCs and are usually considered to break through the restriction (i) . The concept to utilize sub‐bandgap photons by means of two‐step photoexcitation via the IB has been proven using quantum‐confined states in semiconductor QDs, heterointerfaces of wide/narrow‐bandgap semiconductors, anticross bands in highly mismatched semiconductor alloys such as ZnTeO and GaAsN, and impurity states in ZnTe:Cr as the IBs …”

Section: Introductionmentioning

confidence: 99%

Intermediate‐band effect in hot‐carrier solar cells

Takeda

2019

Progress in Photovoltaics

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I have proposed that two-step photoexcitation of carriers is feasible in hot-carrier solar cells (HC-SCs), like that in intermediate-band solar cells (IB-SCs). The second excitation from the IB to the conduction band (CB) in an IB-SC is regarded to make the carriers in the unoccupied band hot. In an analogous way, in an HC-SC, a photoexcited carrier arising from the interband transition can be further excited by the next photon via the intraband transition. In other words, the lower-energy states in the CB function as the IB. Owing to this IB effect, the absorbed energy increases while the excited carrier number decreases under the optimal operating conditions; the latter leads to a decrease in the energy dissipation associated with the hot-carrier extraction. Consequently, the limiting conversion efficiency of the HC-SCs improves by up to 6% to 9% (absolute) compared with that with no IB effect, under the condition of the carrier thermalization time of 1 ns and 1000 times concentrated solar illumination. The detrimental impact of the increase in the emitted energy due to the intraband transition is well suppressed under the suitable operating conditions. Thus, the IB effect always provides positive results even if the effect is weak, contrasting to that the weak second excitation could lower the conversion efficiency of an IB-SC.

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Two-step photon up-conversion solar cells

Cited by 94 publications

References 44 publications

Plasmonic Au/TiO₂‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction

Plasmonic Au/TiO₂‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction

Multiscale in modelling and validation for solar photovoltaics

Intermediate‐band effect in hot‐carrier solar cells

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Two-step photon up-conversion solar cells

Cited by 94 publications

References 44 publications

Plasmonic Au/TiO2‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction

Plasmonic Au/TiO2‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction

Multiscale in modelling and validation for solar photovoltaics

Intermediate‐band effect in hot‐carrier solar cells

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Plasmonic Au/TiO₂‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction

Plasmonic Au/TiO₂‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction