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| Open AccessTwo-dimensional Mo1.33C MXene with divacancy ordering prepared from parent 3D laminate with in-plane chemical ordering
Vacancies in 2D materials can influence their properties, however controlling their formation remains a challenge. Here the authors show that selective etching of a 3D laminate with in-plane chemical ordering results in formation of MXenes with ordered divacancies, as well as elevated conductance and supercapacitance.
- Quanzheng Tao
- , Martin Dahlqvist
- & Johanna Rosen
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Article
| Open AccessA reversible dendrite-free high-areal-capacity lithium metal electrode
Despite recent technological advances, it remains challenging to realize reversible high-areal-capacity lithium metal anodes. Here, the authors demonstrate such an anode by tailoring the top solid electrolyte interphase layer.
- Hui Wang
- , Masaki Matsui
- & Nobuyuki Imanishi
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| Open AccessEnergy scaling of targeted optimal control of complex networks
The energy required to control a dynamical complex network can be prohibitively large when there are only a few control inputs. Here the authors demonstrate that if only a subset of the network is targeted the energy requirements decrease exponentially.
- Isaac Klickstein
- , Afroza Shirin
- & Francesco Sorrentino
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| Open AccessElectrochemical generation of sulfur vacancies in the basal plane of MoS2 for hydrogen evolution
In order to fully utilize sulfur vacancies in MoS2 catalysts for industrial applications, a facile and general route for making sulfur vacancies in MoS2 is needed. Here, the authors introduce a scalable route towards generating sulfur vacancies on the MoS2basal plane using electrochemical desulfurization.
- Charlie Tsai
- , Hong Li
- & Frank Abild-Pedersen
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Article
| Open AccessTwo-step photon up-conversion solar cells
Harvesting incident photons with energy below the bandgap may lead to highly efficient solar cells. By introducing InAs quantum dots at the hetero-interface, Asahiet al. achieve efficient two step photon up-conversion resulting in additional photocurrent and very high external quantum efficiency.
- Shigeo Asahi
- , Haruyuki Teranishi
- & Takashi Kita
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| Open AccessHigh-performance and compact-designed flexible thermoelectric modules enabled by a reticulate carbon nanotube architecture
Thermoelectric modules can generate electricity directly from heat and have applications to waste heat-energy conversion. Here Zhouet al. have fabricated a thermoelectric module based on an air-stable n-type single-walled carbon nanotube sheet which can reach a high power factor of 1500 μWm−1K−2.
- Wenbin Zhou
- , Qingxia Fan
- & Sishen Xie
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Article
| Open AccessA class of liquid anode for rechargeable batteries with ultralong cycle life
Ideal energy storage technologies should be efficient, safe and cost-effective. Here, the authors make progress by using dissolved sodium metal in a solution of biphenyl and ethers as a liquid anode for rechargeable sodium beta-alumina batteries.
- Juezhi Yu
- , Yong-Sheng Hu
- & Liquan Chen
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Article
| Open AccessFoldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium–sulfur batteries
Lithium sulfur batteries show capacity and cost advantages, but suffer from the insulating sulfur, shuttling effect and volume fluctuation. To address these challenges, the authors synthesize foldable composite electrodes with carbon nanotubes interpenetrating metal-organic frameworks.
- Yiyin Mao
- , Gaoran Li
- & Zhan Lin
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| Open AccessRegenerable Cu-intercalated MnO2 layered cathode for highly cyclable energy dense batteries
Manganese oxide cathodes in alkaline solutions combine low cost and high capacity for energy storage, but it has been challenging to combine high capacity and stable cycling in this system. Here authors demonstrate reversible, high-capacity cycling when copper additives are introduced and investigate the transformations involved.
- Gautam G. Yadav
- , Joshua W. Gallaway
- & Sanjoy Banerjee
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Article
| Open AccessConductive porous vanadium nitride/graphene composite as chemical anchor of polysulfides for lithium-sulfur batteries
Lithium sulfur batteries are a promising next generation storage technology. Their performance, however, is subject to the parasitic shuttle effect. Here the authors report a cathode material comprising porous vanadium nitride nanoribbon and graphene to provide anchoring for polysulfides.
- Zhenhua Sun
- , Jingqi Zhang
- & Feng Li
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Article
| Open AccessSynergy of ammonium chloride and moisture on perovskite crystallization for efficient printable mesoscopic solar cells
The commercialization of solar cells based on hybrid perovskites requires challenges of device stability and scalable production to be addressed. Ronget al. report ambient-processed printable mesoscopic perovskite solar cells with a lifetime of over 130 days in ambient air with 30% relative humidity.
- Yaoguang Rong
- , Xiaomeng Hou
- & Hongwei Han
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Article
| Open AccessDirect observation of intrinsic twin domains in tetragonal CH3NH3PbI3
Using low dose transmission electron microscopy, Rothmann, Li, Zhuet al. report direct evidence for twin domains in tetragonal CH3NH3PbI3perovskite. The relevant scale and transition temperature of these twin domains could have implications for perovskite solar cells.
- Mathias Uller Rothmann
- , Wei Li
- & Yi-Bing Cheng
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Article
| Open AccessThe critical role of point defects in improving the specific capacitance of δ-MnO2 nanosheets
Two-dimensional solids are of interest for energy storage due to their large accessible surface area, enabling rapid charge/discharge. Here, the authors quantify the point defects in oxide nanosheets, demonstrating that intentional introduction of charged point defects improves the charge storage behaviour.
- Peng Gao
- , Peter Metz
- & Scott T. Misture
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| Open AccessReversed thermo-switchable molecular sieving membranes composed of two-dimensional metal-organic nanosheets for gas separation
Reducing membrane thickness to nanometre scale should increase the throughput of gas separation sieves. Here, the authors report a sieving membrane composed of two-dimensional metal-organic framework nanosheets, exhibiting both high permeation flux and thermally switchable behaviour.
- Xuerui Wang
- , Chenglong Chi
- & Dan Zhao
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Article
| Open AccessProton enhanced dynamic battery chemistry for aprotic lithium–oxygen batteries
Water is believed to undermine the performance of aprotic lithium–air batteries. However, the authors here disclose different battery chemistry, showing that both lithium ions and protons are involved in the battery reactions in the presence of water, leading to an unprecedented dynamic product.
- Yun Guang Zhu
- , Qi Liu
- & Qing Wang
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| Open AccessSelf-surface charge exfoliation and electrostatically coordinated 2D hetero-layered hybrids
Synthesis of atomically thin 2D hetero-layered structures remains a challenge. Here, the authors report a scalable approach to fabricating 2D hetero-layered metal chalcogenides of various compositions: self-surface charge exfoliation, followed by electrostatic coupling.
- Min-Quan Yang
- , Yi-Jun Xu
- & Ghim Wei Ho
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| Open AccessAcoustic-optical phonon up-conversion and hot-phonon bottleneck in lead-halide perovskites
Slow cooling of hot charge carriers in lead halide perovskite could be used in photovoltaics devices. Here, Yanget al. study hot carrier dynamics by transient absorption spectroscopy. They relate the phonon bottleneck to the up-conversion of low-energy phonons, facilitated by the presence of organic cations.
- Jianfeng Yang
- , Xiaoming Wen
- & Gavin Conibeer
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| Open AccessThermal engineering of FAPbI3 perovskite material via radiative thermal annealing and in situ XRD
Processing is crucial to ensure material quality and stability in perovskite solar cells. Here, Poolet al. develop a scalable infrared annealing method and use in situXRD to map the processing phase space relative to the device efficiency. This provides a tool to determine processing requirements.
- Vanessa L. Pool
- , Benjia Dou
- & Michael F. Toney
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| Open AccessIntragranular cracking as a critical barrier for high-voltage usage of layer-structured cathode for lithium-ion batteries
Cycling-induced fracture can limit conditions for stable operation for various lithium-ion electrode materials. Here, the authors characterize fracture in nickel-manganese-cobalt oxide microscopically and provide evidence for dislocation-assisted, intragranular fracture operating above a critical voltage threshold.
- Pengfei Yan
- , Jianming Zheng
- & Chong-Min Wang
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| Open AccessLong-term efficient organic photovoltaics based on quaternary bulk heterojunctions
Organic photovoltaics suffer from degradation. Here, Namet al. develop a quaternary blend and fabricate devices which lose 28% of their initial efficiency after one year of operation at 65 °C.
- Minwoo Nam
- , Minjeong Cha
- & Doo-Hyun Ko
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| Open AccessSuper-emitters in natural gas infrastructure are caused by abnormal process conditions
A large proportion of methane emissions from natural gas production sites are released by a fraction of high-emitting sources. Here, using Monte Carlo simulations, the authors reveal that super-emitters occur due to abnormal process conditions, explaining component and site-based inventory discrepancies.
- Daniel Zavala-Araiza
- , Ramón A Alvarez
- & Steven P. Hamburg
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| Open AccessHigh power rechargeable magnesium/iodine battery chemistry
Rechargeable magnesium batteries suffer from slow solid-state Mg2+diffusion in the intercalation cathode. Here the authors show magnesium/iodine chemistry in which the liquid–solid two-phase reaction leads to increased rate capabilities by overcoming the sluggish kinetics.
- Huajun Tian
- , Tao Gao
- & Chunsheng Wang
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| Open AccessAugmenting light coverage for photosynthesis through YFP-enhanced charge separation at the Rhodobacter sphaeroides reaction centre
Photosynthesis uses only a limited range of solar radiation. Here, Graysonet al. genetically incorporated the yellow fluorescent protein (YFP) chromophore into a bacterial photosystem, and show that energy harvested by reaction centre–YFP complexes can augment photosynthesis in vivo.
- Katie J. Grayson
- , Kaitlyn M. Faries
- & C. Neil Hunter
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Article
| Open AccessA stable lithiated silicon–chalcogen battery via synergetic chemical coupling between silicon and selenium
Lithium-based batteries employing silicon anodes and sulfur cathodes are promising for combining low cost and high capacity, but have been limited in terms of cycling stability. Here authors present cycling and characterization data supporting beneficial synergies between a selenium disulfide cathode and a silicon anode.
- KwangSup Eom
- , Jung Tae Lee
- & Thomas F. Fuller
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| Open AccessTi3C2 MXene co-catalyst on metal sulfide photo-absorbers for enhanced visible-light photocatalytic hydrogen production
Solar hydrogen production through photocatalytic water splitting requires active and stable co-catalysts to replace platinum. Here, the authors use DFT to identify Ti3C2nanoparticles as potential co-catalysts, and assess their photocatalytic hydrogen production activity.
- Jingrun Ran
- , Guoping Gao
- & Shi-Zhang Qiao
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| Open AccessOrigin of stabilization and destabilization in solid-state redox reaction of oxide ions for lithium-ion batteries
Energy storage by metal redox reactions sets strict limits on capacity in metal oxide cathode materials used in lithium-ion batteries. Here authors study stabilization of redox reactions at oxygen sites and demonstrate a cathode with a high reversible capacity enabled by the process.
- Naoaki Yabuuchi
- , Masanobu Nakayama
- & Toshiaki Ohta
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Article
| Open AccessFluorination-enabled optimal morphology leads to over 11% efficiency for inverted small-molecule organic solar cells
Organic solar cells based on solution-processable small molecules still lag behind their macromolecule counterparts. Here, Denget al. develop molecular donors to pair with PC71BM and study how the degree of fluorination impacts the morphology of the heterojunction and the efficiency of the devices.
- Dan Deng
- , Yajie Zhang
- & Zhixiang Wei
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| Open AccessImprovement of system capacitance via weavable superelastic biscrolled yarn supercapacitors
Carbon nanotube yarns with high loadings of pseudocapacitive material are desirable, e.g., for emerging wearable technologies. Here authors make biscrolled yarns with high loadings of MnO2nanoparticles confined in carbon nanotube galleries, demonstrating very high linear and areal capacitances.
- Changsoon Choi
- , Kang Min Kim
- & Seon Jeong Kim
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| Open AccessHetero-type dual photoanodes for unbiased solar water splitting with extended light harvesting
Metal oxide semiconductors are promising photoelectrode materials for solar water splitting but their efficiency needs to be improved. Here, the authors report a hetero-type dual photoelectrode strategy in which two photoanodes of different band gaps are connected in parallel for extended light harvesting.
- Jin Hyun Kim
- , Ji-Wook Jang
- & Jae Sung Lee
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| Open AccessRadiative cooling to deep sub-freezing temperatures through a 24-h day–night cycle
Radiative cooling relies on the atmosphere’s transparency window. Here the authors achieve up to 42 °C drops in temperature for low thermal loads under diffuse sunlight by improving the selectivity of the emissivity and the thermal management of their devices.
- Zhen Chen
- , Linxiao Zhu
- & Shanhui Fan
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| Open AccessCo-axial heterostructures integrating palladium/titanium dioxide with carbon nanotubes for efficient electrocatalytic hydrogen evolution
Hydrogen evolution by water electrolysis is a promising route to 'green energy', but efficiency is still an issue. Here, the authors make mixed organic/inorganic hierarchical nanostructures with high hydrogen evolution activity, identifying synergic effects in the material contributing to enhanced efficiency.
- Giovanni Valenti
- , Alessandro Boni
- & Francesco Paolucci
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| Open AccessObservation of spin Seebeck contribution to the transverse thermopower in Ni-Pt and MnBi-Au bulk nanocomposites
The spin Seebeck effect enables thermal-to-electrical energy conversion but the power generated in thin films remains low. Here, Boonaet al. use composites of ferromagnetic conductors containing noble metal nanoparticles to show that the effect can enhance the transverse thermopower of bulk materials.
- Stephen R. Boona
- , Koen Vandaele
- & Joseph P. Heremans
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| Open AccessRe-assessment of net energy production and greenhouse gas emissions avoidance after 40 years of photovoltaics development
While the photovoltaic industry aims to achieve cleaner energy production, it consumes energy and emits greenhouse gases during production and deployment. Here, Louwenet al. show that the industry has likely already reached break-even points for both greenhouse gases emissions and electricity consumption.
- Atse Louwen
- , Wilfried G. J. H. M. van Sark
- & Ruud E. I. Schropp
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| Open AccessEfficiency limits for photoelectrochemical water-splitting
Theoretical limiting efficiencies play a critical role in determining technological viability and expectations for device prototypes. Here, the authors present a unified framework for photoelectrochemical device performance through which previous limiting efficiencies can be understood and contextualized.
- Katherine T. Fountaine
- , Hans Joachim Lewerenz
- & Harry A. Atwater
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| Open AccessConfirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000
Early stellarator designs suffered from high particle losses, an issue that can be addressed by optimization of the coils. Here the authors measure the magnetic field lines in the Wendelstein 7-X stellarator, confirming that the complicated design of the superconducting coils has been realized successfully.
- T. Sunn Pedersen
- , M. Otte
- & Sandor Zoletnik
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| Open AccessSelf-assembly of diphenylalanine peptide with controlled polarization for power generation
Piezoelectricity in diphenylalanine peptide nanotubes (PNTs) suggests an avenue towards green piezoelectric devices. Here the authors show ‘smart’ PNTs whose polarization can be controlled with an electric field, and a resultant power generator which harvests biomechanical energy with high power density.
- Vu Nguyen
- , Ren Zhu
- & Rusen Yang
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| Open AccessA hyperaccumulation pathway to three-dimensional hierarchical porous nanocomposites for highly robust high-power electrodes
Hyperaccumulation can allow facile enrichment of metal ions in halophytic plants. Here, the authors use the effect to convert plant structures into hierarchical carbon/metal-oxide nanocomposites and demonstrate the structures as battery electrodes combining high power density and excellent cycling stability.
- Jian Zhu
- , Yu Shan
- & Xiangfeng Duan
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Article
| Open AccessBivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage
Rechargeable aqueous electrochemical energy storage is a promising technology but suffers from a narrow potential window. Here the authors report a surface hydroxylated Mn5O8pseudocapacitor electrode with bivalence structure that expands the potential window to deliver high energy and power performance.
- Xiaoqiang Shan
- , Daniel S. Charles
- & Xiaowei Teng
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Article
| Open AccessWearable energy-smart ribbons for synchronous energy harvest and storage
Flexible materials for harvesting and storing energy are desirable for wearable electronics, but efficiency is still an issue. Here, the authors demonstrate a flexible and weavable ribbon which integrates a solar cell and supercapacitor via a shared electrode for efficient energy harvesting and storage.
- Chao Li
- , Md. Monirul Islam
- & Jayan Thomas
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Article
| Open AccessHigh-performance shape-engineerable thermoelectric painting
Thermoelectric devices are often rigid and do not adapt conformally to surfaces. Here, Park et al. prepare a Bi2Te3-based thermoelectric paint, containing a Sb2Te3chalcogenidometalate additive, that can be paint-brushed onto curved surfaces and form thermoelectric modules with good efficiencies.
- Sung Hoon Park
- , Seungki Jo
- & Jae Sung Son
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Article
| Open AccessTrapped charge-driven degradation of perovskite solar cells
Improving the stability of perovskite solar cells remains crucial. Here, Ahn et al. show that trapped charges at grain boundaries induce the dissociation of the perovskite compound in the presence of moisture, and explain why degradation is irreversible under illumination and reversible in the dark.
- Namyoung Ahn
- , Kwisung Kwak
- & Mansoo Choi
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Article
| Open AccessSolar water splitting by photovoltaic-electrolysis with a solar-to-hydrogen efficiency over 30%
In order to be practical for large-scale deployment, the cost of solar hydrogen generation must be significantly reduced. Here, the authors employ a triple-junction solar cell with two series connected polymer electrolyte membrane electrolysers to achieve solar to hydrogen efficiency of 30%.
- Jieyang Jia
- , Linsey C. Seitz
- & Thomas F. Jaramillo
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Article
| Open AccessIn situ electrochemical quantification of active sites in Fe–N/C non-precious metal catalysts
Fe-N/C catalysts show surprising activity towards oxygen reduction in fuel cells. However, there is significant uncertainty as to the structure of the active site. Here, the authors quantify the number and turnover frequency of the active sites by reversibly blocking those sites with nitrite (NO2¯).
- Daniel Malko
- , Anthony Kucernak
- & Thiago Lopes
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Article
| Open AccessDonor polymer design enables efficient non-fullerene organic solar cells
In organic photovoltaics, electron acceptors are developed to replace fullerenes, and new donors need to be designed to match these acceptors. Here, the authors show that a polymer with strong temperature dependent aggregation and intentionally reduced crystallinity matches non-fullerene acceptors.
- Zhengke Li
- , Kui Jiang
- & He Yan
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Article
| Open AccessIn-depth analysis of chloride treatments for thin-film CdTe solar cells
High performance CdTe thin film solar cells typically require a chloride activation treatment. Here, Majoret al. show that the main effect of the most effective chloride-based treatments is chloride accumulation at grain boundaries and that it results in improved open circuit voltages.
- J. D. Major
- , M. Al Turkestani
- & K. Durose
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| Open AccessThermally enhanced photoluminescence for heat harvesting in photovoltaics
In photovoltaics, sub-band gap energy photons can be harvested using up-conversion strategies. Here, the authors show that the thermally enhanced up-converted photoluminescence results in enhanced energy conversion, for an accessible temperature range and with a broad range of incident photon energy.
- Assaf Manor
- , Nimrod Kruger
- & Carmel Rotschild
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Article
| Open AccessA sulfur host based on titanium monoxide@carbon hollow spheres for advanced lithium–sulfur batteries
The promise of lithium-sulfur batteries with higher energy densities than lithium-ion is hindered by the insulating nature of sulfur and dissolution of polysulfides. Here the authors design titanium monoxide/carbon hollow nanospheres that overcome both obstacles, enabling improved electrochemical properties.
- Zhen Li
- , Jintao Zhang
- & Xiong Wen (David) Lou
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Article
| Open AccessPhoto-excited charge carriers suppress sub-terahertz phonon mode in silicon at room temperature
Direct measurement of electron-phonon interactions at the single-mode level has been a challenge. Here, Liaoet al. use a three-pulse photoacoustic spectroscopy technique to investigate the damping of a single sub-terahertz coherent phonon mode by photo-excited free charge carriers in silicon at room temperature.
- Bolin Liao
- , A. A. Maznev
- & Gang Chen
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| Open AccessTheory of highly efficient multiexciton generation in type-II nanorods
Multiple exciton generation could help limit thermalization losses in solar cells, but the efficiency of the process is still limited. Here, the authors show by atomistic calculations that type-II interfaces in nanostructures along with a change in exciton cooling rate favour multiple exciton generation.
- Hagai Eshet
- , Roi Baer
- & Eran Rabani