| 1. |
- Romanelli, F, et al.
(författare)
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Overview of the JET results
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
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Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
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| 2. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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| 3. |
- Abramowicz, H., et al.
(författare)
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Conceptual design report for the LUXE experiment
- 2021
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Ingår i: European Physical Journal-Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 230:11, s. 2445-2560
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Tidskriftsartikel (refereegranskat)abstract
- This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the European XFEL with a powerful laser to explore the uncharted terrain of quantum electrodynamics characterised by both high energy and high intensity. We will reach this hitherto inaccessible regime of quantum physics by analysing high-energy electron-photon and photon-photon interactions in the extreme environment provided by an intense laser focus. The physics background and its relevance are presented in the science case which in turn leads to, and justifies, the ensuing plan for all aspects of the experiment: Our choice of experimental parameters allows (i) field strengths to be probed where the coupling to charges becomes non-perturbative and (ii) a precision to be achieved that permits a detailed comparison of the measured data with calculations. In addition, the high photon flux predicted will enable a sensitive search for new physics beyond the Standard Model. The initial phase of the experiment will employ an existing 40 TW laser, whereas the second phase will utilise an upgraded laser power of 350 TW. All expectations regarding the performance of the experimental set-up as well as the expected physics results are based on detailed numerical simulations throughout.
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| 4. |
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| 5. |
- Fukuzawa, H., et al.
(författare)
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Deep Inner-Shell Multiphoton Ionization by Intense X-Ray Free-Electron Laser Pulses
- 2013
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 110:17
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated multiphoton multiple ionization dynamics of xenon atoms using a new x-ray free-electron laser facility, SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan, and identified that Xen+ with n up to 26 is produced at a photon energy of 5.5 keV. The observed high charge states (n >= 24) are produced via five-photon absorption, evidencing the occurrence of multiphoton absorption involving deep inner shells. A newly developed theoretical model, which shows good agreement with the experiment, elucidates the complex pathways of sequential electronic decay cascades accessible in heavy atoms. The present study of heavy-atom ionization dynamics in high-intensity hard-x-ray pulses makes a step forward towards molecular structure determination with x-ray free-electron lasers. DOI: 10.1103/PhysRevLett.110.173005
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| 6. |
- Heard, J. M., et al.
(författare)
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Availability, accessibility and delivery to patients of the 28 orphan medicines approved by the European Medicine Agency for hereditary metabolic diseases in the MetabERN network
- 2020
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Ingår i: Orphanet Journal of Rare Diseases. - : Springer Science and Business Media LLC. - 1750-1172. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background The European Medicine Agency granted marketing approval to 164 orphan medicinal products for rare diseases, among which 28 products intended for the treatment of hereditary metabolic diseases. Taking advantage of its privileged connection with 69 healthcare centres of excellence in this field, MetabERN, the European Reference Network for hereditary metabolic diseases, performed a survey asking health care providers from 18 European countries whether these products are available on the market, reimbursed and therefore accessible for prescription, and actually delivered in their centre. Results Responses received from 52 centres (75%) concerned the design of treatment plans, the access to marketed products, and the barriers to delivery. Treatment options are always discussed with patients, who are often involved in their treatment plan. Most products (26/28) are available in most countries (15/18). Among the 15 broadly accessible products (88.5% of the centres), 9 are delivered to most patients (mean 70.1%), and the others to only few (16.5%). Among the 10 less accessible products (40.2% of the centres), 6 are delivered to many patients (66.7%), and 4 are rarely used (6.3%). Information was missing for 3 products. Delay between prescription and delivery is on average one month. Beside the lack of availability or accessibility, the most frequent reasons for not prescribing a treatment are patients' clinical status, characteristic, and personal choice. Conclusions Data collected from health care providers in the MetabERN network indicate that two-third of the orphan medicines approved by EMA for the treatment of hereditary metabolic diseases are accessible to treating patients, although often less than one-half of the patients with the relevant conditions actually received the approved product to treat their disease. Thus, in spite of the remarkable achievement of many products, patients concerned by EMA-approved orphan medicinal products have persistent unmet needs, which deserve consideration. The enormous investments made by the companies to develop products, and the high financial burden for the Member States to purchase these products emphasize the importance of a scrupulous appreciation of treatment value involving all stakeholders at early stage of development, before marketing authorization, and during follow up.
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| 7. |
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| 8. |
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| 9. |
- Motomura, K., et al.
(författare)
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Sequential multiphoton multiple ionization of atomic argon and xenon irradiated by X-ray free-electron laser pulses from SACLA
- 2013
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:16
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated multiphoton multiple ionization of argon and xenon atoms at 5 keV using a new x-ray free electron laser (XFEL) facility, the SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan. The experimental results are compared with the new theoretical results presented here. The absolute fluence of the XFEL pulse has been determined with the help of the calculations utilizing two-photon processes in the argon atom. The high charge states up to +22 observed for Xe in comparison with the calculations point to the occurrence of sequential L-shell multiphoton absorption and of resonance-enabled x-ray multiple ionization.
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| 10. |
- Murphy, B. F., et al.
(författare)
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Femtosecond X-ray-induced explosion of C-60 at extreme intensity
- 2014
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Understanding molecular femtosecond dynamics under intense X-ray exposure is critical to progress in biomolecular imaging and matter under extreme conditions. Imaging viruses and proteins at an atomic spatial scale and on the time scale of atomic motion requires rigorous, quantitative understanding of dynamical effects of intense X-ray exposure. Here we present an experimental and theoretical study of C-60 molecules interacting with intense X-ray pulses from a free-electron laser, revealing the influence of processes not previously reported. Our work illustrates the successful use of classical mechanics to describe all moving particles in C-60, an approach that scales well to larger systems, for example, biomolecules. Comparisons of the model with experimental data on C-60 ion fragmentation show excellent agreement under a variety of laser conditions. The results indicate that this modelling is applicable for X-ray interactions with any extended system, even at higher X-ray dose rates expected with future light sources.
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| 11. |
- Ortigoza-Escobar, J. D., et al.
(författare)
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Thiamine deficiency in childhood with attention to genetic causes: Survival and outcome predictors
- 2017
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Ingår i: Annals of Neurology. - : Wiley. - 0364-5134. ; 82:3, s. 317-330
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Tidskriftsartikel (refereegranskat)abstract
- Primary and secondary conditions leading to thiamine deficiency have overlapping features in children, presenting with acute episodes of encephalopathy, bilateral symmetric brain lesions, and high excretion of organic acids that are specific of thiamine-dependent mitochondrial enzymes, mainly lactate, alpha-ketoglutarate, and branched chain keto-acids. Undiagnosed and untreated thiamine deficiencies are often fatal or lead to severe sequelae. Herein, we describe the clinical and genetic characterization of 79 patients with inherited thiamine defects causing encephalopathy in childhood, identifying outcome predictors in patients with pathogenic SLC19A3 variants, the most common genetic etiology. We propose diagnostic criteria that will aid clinicians to establish a faster and accurate diagnosis so that early vitamin supplementation is considered. Ann Neurol 2017;82:317–330. © 2017 American Neurological Association
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| 12. |
- Roger, T., et al.
(författare)
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Precise Determination of the Unperturbed B8 Neutrino Spectrum
- 2012
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Ingår i: Phys. Rev. Lett.. ; 108:16, s. Art. no. 162502-
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Tidskriftsartikel (refereegranskat)abstract
- A measurement of the final state distribution of the 8B beta decay, obtained by implanting a 8B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyvaskyla [O. S.Kirsebom et al., Phys. Rev. C 83, 065802 (2011)]. It shows discrepancies with previously measuredspectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, theneutrino spectrum is for the first time directly extracted from the measured final state distribution, thusavoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data,this leads to an improvement of the overall errors and the extension of the neutrino spectrum at highenergy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of thesolar neutrino flux as a function of energy.
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| 13. |
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| 14. |
- van Kuilenburg, Andre B. P., et al.
(författare)
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Glutaminase Deficiency Caused by Short Tandem Repeat Expansion in GLS
- 2019
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 380:15, s. 1433-1441
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Tidskriftsartikel (refereegranskat)abstract
- We report an inborn error of metabolism caused by an expansion of a GCA-repeat tract in the 5′ untranslated region of the gene encoding glutaminase (GLS) that was identified through detailed clinical and biochemical phenotyping, combined with whole-genome sequencing. The expansion was observed in three unrelated patients who presented with an early-onset delay in overall development, progressive ataxia, and elevated levels of glutamine. In addition to ataxia, one patient also showed cerebellar atrophy. The expansion was associated with a relative deficiency of GLS messenger RNA transcribed from the expanded allele, which probably resulted from repeat-mediated chromatin changes upstream of the GLS repeat. Our discovery underscores the importance of careful examination of regions of the genome that are typically excluded from or poorly captured by exome sequencing.
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| 15. |
- Bai, Z., et al.
(författare)
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New physics searches with an optical dump at LUXE
- 2022
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Ingår i: Physical Review D. - 2470-0010. ; 106:11
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Tidskriftsartikel (refereegranskat)abstract
- We propose a novel way to search for feebly interacting massive particles, exploiting two properties of systems involving collisions between high energy electrons and intense laser pulses. The first property is that the electron-laser collision results in a large flux of hard photons, as the laser behaves effectively as a thick medium. The second property is that the emitted photons free-stream inside the laser and thus for them the laser behaves effectively as a very thin medium. Combining these two features implies that the electron-intense-laser collision is an apparatus, which can efficiently convert O(10 GeV) electrons to a large flux of hard, collinear photons. The photons are directed onto a solid dump in which feebly interacting massive particles may be produced. With the much smaller backgrounds induced by the photon beam compared to those expected in electron- or proton-beam dump experiments and combined with a relatively shorter dump used here, the sensitivity to short lifetimes is unparalleled. We denote this novel apparatus as "optical dump"or NPOD (new physics search with optical dump). The proposed LUXE experiment at the European XFEL has all the basic required ingredients to realize this experimental concept for the first time. Moreover, the NPOD extension of LUXE is essentially parasitic to the main experiment and thus, practically it does not have any bearing on its main program. We discuss how the NPOD concept can be realized in practice by adding a detector after the last physical dump of the experiment to reconstruct the two-photon decay of a new spin-0 particle. We show that even with a relatively short dump, the search can still be background-free. Remarkably, even with a few days of data taking with a 40 TW laser corresponding to its initial run, LUXE-NPOD will be able to probe an uncharted territory of models with pseudoscalars and scalars. Furthermore, with a 350 TW laser of the main run, LUXE-NPOD will have a unique reach for these models. In particular it can probe natural scalar theories for masses above 100 MeV. We note that the new NPOD concept may be ported to other existing or future facilities worldwide, including, e.g., future lepton colliders.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Tachibana, T., et al.
(författare)
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Nanoplasma Formation by High Intensity Hard X-rays
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at similar to 5 keV. Our experiment was carried out at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with the molecular dynamics tool XMDYN. We found that in this unprecedented wavelength regime nanoplasma formation is a highly indirect process. In the argon clusters investigated, nanoplasma is mainly formed through secondary electron cascading initiated by slow Auger electrons. Energy is distributed within the sample entirely through Auger processes and secondary electron cascading following photoabsorption, as in the hard x-ray regime there is no direct energy transfer from the field to the plasma. This plasma formation mechanism is specific to the hard-x-ray regime and may, thus, also be important for XFEL-based molecular imaging studies. In xenon clusters, photo-and Auger electrons contribute more significantly to the nanoplasma formation. Good agreement between experiment and simulations validates our modelling approach. This has wide-ranging implications for our ability to quantitatively predict the behavior of complex molecular systems irradiated by high-intensity hard x-rays.
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| 20. |
- Ueda, Kiyoshi, et al.
(författare)
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Roadmap on photonic, electronic and atomic collision physics : I. Light-matter interaction
- 2019
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Ingår i: Journal of Physics B. - : IOP PUBLISHING LTD. - 0953-4075 .- 1361-6455. ; 52:17
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Tidskriftsartikel (refereegranskat)abstract
- We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. In Roadmap I, we focus on the light-matter interaction. In this area, studies of ultrafast electronic and molecular dynamics have been rapidly growing, with the advent of new light sources such as attosecond lasers and x-ray free electron lasers. In parallel, experiments with established synchrotron radiation sources and femtosecond lasers using cutting-edge detection schemes are revealing new scientific insights that have never been exploited. Relevant theories are also being rapidly developed. Target samples for photon-impact experiments are expanding from atoms and small molecules to complex systems such as biomolecules, fullerene, clusters and solids. This Roadmap aims to look back along the road, explaining the development of these fields, and look forward, collecting contributions from twenty leading groups from the field.
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| 21. |
- Zhang, Xiaoliang, et al.
(författare)
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Highly Efficient Flexible Quantum Dot Solar Cells with Improved Electron Extraction Using MgZnO Nanocrystals
- 2017
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 11:8, s. 8478-8487
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Tidskriftsartikel (refereegranskat)abstract
- Colloidal quantum dot (CQD) solar cells have high potential for realizing an efficient and lightweight energy supply for flexible or wearable electronic devices. To achieve highly efficient and flexible CQD solar cells, the electron transport layer (ETL), extracting electrons from the CQD solid layer, needs to be processed at a low-temperature and should also suppress interfacial recombination. Herein, a highly stable MgZnO nanocrystal (MZO-NC) layer is reported for efficient flexible PbS CQD solar cells. Solar cells fabricated with MZONC ETL give a high power conversion efficiency (PCE) of 10.4% and 9.4%, on glass and flexible plastic substrates, respectively. The reported flexible CQD solar cell has the record efficiency to date of flexible CQD solar cells. Detailed theoretical simulations and extensive characterizations reveal that the MZO-NCs significantly enhance charge extraction from CQD solids and diminish the charge accumulation at the ETL/CQD interface, suppressing charge interfacial recombination. These important results suggest that the low-temperature processed MZO-NCs are very promising for use in efficient flexible solar cells or other flexible optoelectronic devices.
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