| 1. |
- Cheng, Peirui, et al.
(författare)
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Highly Efficient Ruddlesden–Popper Halide Perovskite PA2MA4Pb5I16 Solar Cells
- 2018
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 3:8, s. 1975-1982
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) Ruddlesden-Popper (RP) organic-inorganic perovskites have emerged as promising candidates for solar cells with technologically relevant stability. Herein, a new RP perovskite, the fifth member («n» = 5) of the (CH3(CH2)2NH3)2(CH3NH3)n-1PbnI3n+1 family (abbreviated as PA2MA4Pb5I16), was synthesized and systematically investigated in terms of photovoltaic application. The obtained pure PA2MA4Pb5I16 crystal exhibits a direct band gap of Eg = 1.85 eV. Systematic analysis on the solid film highlights the key role of the precursor-solvent interaction in the quantum well orientation, phase purity, grain size, surface quality, and optoelectronic properties, which can be well-tuned with addition of dimethyl sulfoxide (DMSO) into the N,N-dimethylformamide (DMF) precursor solution. These findings present opportunities for designing a high-quality RP film with well-controlled quantum well orientation, micrometer-sized grains, and optoelectronic properties. As a result, we achieved power conversion efficiency (PCE) up to 10.41%.
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| 2. |
- Jia, Xue, et al.
(författare)
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CsPb(IxBr1-x)(3) solar cells
- 2019
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Ingår i: Science Bulletin. - : ELSEVIER. - 2095-9273. ; 64:20, s. 1532-1539
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Tidskriftsartikel (refereegranskat)abstract
- Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell (PSC) becomes a promising candidate for next-generation high-efficiency solar cells. The power conversion efficiency (PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)(3) and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)(3) solar cells and outline possible directions to further improve the device performance. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.
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| 3. |
- Liu, Zonghao, et al.
(författare)
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Gas-solid reaction based over one-micrometer thick stable perovskite films for efficient solar cells and modules
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Besides high efficiency, the stability and reproducibility of perovskite solar cells (PSCs) are also key for their commercialization. Herein, we report a simple perovskite formation method to fabricate perovskite films with thickness over 1 mu m in ambient condition on the basis of the fast gas-solid reaction of chlorine-incorporated hydrogen lead triiodide and methylamine gas. The resultant thick and smooth chlorine-incorporated perovskite films exhibit full coverage, improved crystallinity, low surface roughness and low thickness variation. The resultant PSCs achieve an average power conversion efficiency of 19.1 +/- 0.4% with good reproducibility. Meanwhile, this method enables an active area efficiency of 15.3% for 5 cmx 5 cm solar modules. The un-encapsulated PSCs exhibit an excellent T-80 lifetime exceeding 1600 h under continuous operation conditions in dry nitrogen environment.
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| 4. |
- Qin, Ru, et al.
(författare)
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Highly Stretchable Conjugated Polymer/Elastomer Blend Films with Sandwich Structure
- 2023
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Ingår i: Macromolecular rapid communications. - : WILEY-V C H VERLAG GMBH. - 1022-1336 .- 1521-3927.
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Tidskriftsartikel (refereegranskat)abstract
- The physical blending of high-mobility conjugated polymers with ductile elastomers provides a simple way to realize high-performance stretchable films. However, how to control the morphology of the conjugated polymer and elastomer blend film and its response to mechanical fracture processes during stretching are not well understood. Herein, a sandwich structure is constructed in the blend film based on a conjugated polymer poly[(5-fluoro-2,1,3-benzothiadiazole-4,7-diyl)(4,4-dihexadecyl-4H-cyclopenta[2,1-b:3,4-b & DPRIME;]dithiophene-2,6-diyl)(6-fluoro-2,1,3-benzothiadiazole-4,7-diyl)(4,4-dihexadecyl-4H-cyclopenta[2,1-b:3,4-b & DPRIME;]dithiophene-2,6-diyl)] (PCDTFBT) and an elastomer polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS). The sandwich structure is composed of a PCDTFBT:SEBS mixed layer laminated with a PCDTFBT-rich layer at both the top and bottom surfaces. During stretching, the external strain energy can be effectively dissipated by the deformation of the crystalline PCDTFBT domains and amorphous SEBS phases and the recrystallization of the PCDTFBT chains. This endows the blend film with excellent ductility, with a large crack onset strain exceeding 1100%, and minimized the electrical degradation of the blend film at a large strain. This study indicates that the electrical and mechanical performance of conjugated polymer/elastomer blend films can be improved by manipulating their microstructure.
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| 5. |
- Su, Yueling, et al.
(författare)
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Carrier Generation Engineering toward 18% Efficiency Organic Solar Cells by Controlling Film Microstructure
- 2022
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 12:19
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Tidskriftsartikel (refereegranskat)abstract
- The single bulk-heterojunction active layer based on non-fullerene acceptors (NFAs) has dominated the power conversional efficiencies above 18% in state-of-the-art organic solar cells (OSCs). However, a deep understanding of the relationship between charge carrier process and film microstructure remains unclear for emerging NFA OSCs. Herein, with the superstar PM6:Y6 blend as a model, the charge generation process in active layers is successfully manipulated by designing three different film microstructures, and they are correlated with the final photovoltaic performance in OSC devices. The amount of intermediate intra-moiety excited states from the nanoscale Y6 aggregates can be effectively enhanced by controlling the phase separation domains and film crystallinity in the bicontinuous PM6:Y6 networks. This robustly improves the hole transfer, and thus promotes charge generation. As a result, the optimal films show superior device performance, that is, the high efficiencies of 16.53% and 17.98% for PM6:Y6- and D18:Y6-based single junction OSCs, respectively. The results presented here give a rational guide for optimizing the charge carrier process through controlling morphological microstructures toward high-performance NFA OSCs.
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| 6. |
- Su, Yueling, et al.
(författare)
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High-efficiency organic solar cells processed from a halogen-free solvent system
- 2023
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Ingår i: Science in China Series B. - : SCIENCE PRESS. - 1674-7291 .- 1869-1870. ; 66:8, s. 2380-2388
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Tidskriftsartikel (refereegranskat)abstract
- The use of non-halogenated solvents for the green manufacture of high-efficiency organic solar cells (OSCs) is important for their future application. However, the power conversion efficiency (PCE) of the non-halogenated solvent processed OSCs is generally lower than their halogenated counterpart due to the poor film microstructure caused by the solubility issue. Herein, we propose a halogen-free solvent system to optimize film microstructure of the photovoltaic blend based on the polymer donor D18 and small-molecule acceptor (SMA) L8-BO towards high-efficiency OSCs. The solvent system is consisted of a main solvent carbon disulfide and an additive paraxylene, where the former ensures the good solution-processability and promotes the solution aggregation of L8-BO, and the latter can finely control the phase-separation process by selectively dissolving the SMA. This solvent combination robustly produces a high-quality active layer, i.e., the bicontinuous networks of donor and acceptor with nano-sized phase-separation and strong & pi;-& pi; stacking. With the effective charge generation, transport and collection, the resulting device from the non-halogenated solvent system shows a high PCE of 17.50%, which is comparable to that of the device prepared from the halogenated solvent chloroform (ca. 17.11%). This article proposes a new strategy for the green fabrication of high-efficiency OSCs to accelerate their industrialization.
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| 7. |
- Xiang, Wanchun, et al.
(författare)
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Intermediate phase engineering of halide perovskites for photovoltaics
- 2022
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Ingår i: Joule. - : Elsevier. - 2542-4351. ; 6:2, s. 315-339
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Forskningsöversikt (refereegranskat)abstract
- Metal halide perovskites serving as one of the most promising photovoltaic materials are gaining considerable attention worldwide. For achieving high performance as well as long-term stability of the perovskite solar cells (PSCs), a good quality of perovskite film featuring in smooth, pinhole-free morphology, full coverage over substrates, good heterojunction contacts, and stable photoactive phase is of great importance. During solution fabrication for perovskite films, intermediate phase, which refers to the state of precursor composition before final annealing, plays an essential role in determining the film quality, especially in the state-of-theart PSCs. In this review, we summarize the research involving mechanism and applications of intermediate phase engineering (IPE) processes in various solution-processing technologies. The challenges of IPE are further discussed, and perspectives are provided for developing high-performance PSCs via IPE.
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| 8. |
- Yi, Wei, et al.
(författare)
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Trauma infant neurologic score predicts the outcome of traumatic brain injury in infants
- 2010
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Ingår i: Pediatric Neurosurgery. - : S. Karger AG. - 1016-2291 .- 1423-0305. ; 46:4, s. 259-266
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the clinical features of infancy traumatic brain injury (TBI) and the prognostic value of the Trauma Infant Neurologic Score (TINS), infants < 2 years of age with TBI who were admitted from 2000 to 2007 were retrospectively studied. Fifty-six patients with a mean age of 13.3 ± 6.5 months (range = 2-24) were identified. The clinical diagnoses, in terms of the severest injury, included scalp hematomas (n = 2), skull bone fractures (n = 3), epidural hematomas (n = 21), subdural hematomas (n = 14), cerebral contusion and laceration (n = 4), intracerebral hematomas (n = 7), traumatic subarachnoid hemorrhage (n = 2), diffuse axonal injury (n = 2) and diffuse brain swelling (n = 1). The most common clinical presentations were vomiting (66.1%), paleness (55.4%), irritability (37.3%), pupillary abnormalities (35.7%) and altered consciousness (32.1%). The mechanism of injury included falls (n = 41), vehicle accident (n = 9), abuse (n = 4) and unknown (n = 2). The TINS score ranged from 1 to 10 with a mean of 3.6 (SD = 2.4) in the whole patient cohort. The Children's Coma Scores (CCS) on admission were 13-15 (n = 31), 9-12 (n = 7) and 3-8 (n = 18). Thirty-nine of the infants were operated on and the other 17 infants were treated nonsurgically. Forty-eight patients (86%) were followed up for a period of 1-8 years (mean = 4.4) after discharge. In the followed-up patient cohort, the mean TINS score at admission was 3.8 ± 2.5. The total clinical outcome, according to the Glasgow Outcome Scale (GOS), was: 37 (77.1%) good recovery, 4 (8.3%) moderately disabled, 1 (2.1%) vegetative and 6 (12.5%) dead. For those who were operated on the outcome was: 25 (78.1%) good recovery, 4 (12.5%) moderately disabled and 3 (9.4%) dead, and for those who were not operated on: 12 (75.0%) good recovery, 1 (6.3%) vegetative and 3 (25.0%) dead. At two years of follow-up, the GOS included 34 (73.9%) good recovery, 3 (6.5%) moderately disabled, 2 (4.3%) severely disabled, 1 (2.2%) vegetative and 6 (13.0%) dead. Statistical tests revealed that the TINS scores were highly associated with the GOS. Higher TINS scores resulted in worse clinical outcome. The CCS scores were also to some degree associated with the GOS score. However, the CCS score on admission was not as discriminating as TINS, predicting only the best and worst outcome in our series. Our study showed that the clinical features of TBI in infants were different from those seen in adults regarding both the distribution of the pathology type and the clinical presenting symptoms. We found that the TINS scoring system is useful for predicting prognosis and outcome in infancy TBI and suggest that it could be routinely used in the infantile population.
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| 9. |
- Zhao, Shengzhong, et al.
(författare)
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A theoretical and experimental study on the buoyancy-driven smoke flow in a tunnel with vertical shafts
- 2019
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Ingår i: International journal of thermal sciences. - : Elsevier BV. - 1290-0729 .- 1778-4166. ; 141, s. 33-46
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a series of small-scale experiments was carried out in a model scale tunnel with dimensions of 20 m (Length) × 2 m (Width) × 1 m (Height) to investigate the characteristics of buoyancy-driven smoke flow in a tunnel with vertical shafts. Different shaft settings and four different longitudinal ventilation velocities were tested in the experiments. A theoretical model for the mass flow rate of buoyancy-driven smoke flow in the shaft was developed and validated. The gas temperature along the tunnel ceiling and smoke stratification were subsequently analyzed and discussed. The results showed that more shafts, greater shaft heights and greater shaft cross sectional areas can significantly increase the smoke extraction rate, and the total smoke mass flow rate in the shafts increases with the increasing ventilation velocity. The local pressure loss coefficient at the shaft inlet may not be a fixed value. An average value of 1.0 for this coefficient was recommended for engineering estimation and design of rectangular-shaped natural shafts. The presence of vertical shaft is beneficial to the smoke stratification and could increase the height of the smoke layer interface, especially for the downstream of the shaft.
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| 10. |
- Zhao, Shengzhong, et al.
(författare)
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Re-direction of smoke flow in inclined tunnel fires
- 2019
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Ingår i: Tunnelling and Underground Space Technology. - : Elsevier BV. - 0886-7798 .- 1878-4364. ; 86, s. 113-127
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Tidskriftsartikel (refereegranskat)abstract
- The re-direction of smoke flow in inclined tunnel fires refers to the phenomenon that the smoke flow direction suddenly changes due to the changes of thermal buoyancy or outside pressure or the activation of fans. This poses special risk for fire rescue services fighting fires in tunnels. Both small-scale tunnel fire tests (28 scenarios) and numerical simulations of full-scale tunnel fires (31 scenarios) were conducted to study this special phenomenon. A one-dimensional model was used to predict the flow velocity in the inclined tunnels, based on two different methods for calculating the mean smoke temperature (Method I and Method II, respectively). Results show that the smoke flow direction could be well predicted by the model with Method II. When the ventilation velocity is relatively large and the flow tends to be one dimensional, both methods produce similar results. Further, the influences of important factors on the re-direction of smoke flows were systematically analyzed. These factors include heat release rate, tunnel slope, tunnel length, friction factor, tunnel cross sectional area and fire source location.
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| 11. |
- Zhao, Shengzhong, et al.
(författare)
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Theoretical and numerical study on smoke descent during tunnel fires under natural ventilation condition
- 2023
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Ingår i: Tunnelling and Underground Space Technology. - : Elsevier Ltd. - 0886-7798 .- 1878-4364. ; 142
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Tidskriftsartikel (refereegranskat)abstract
- The smoke stratification and the smoke descent along a tunnel are of the utmost importance for personnel evacuation. The paper investigates the smoke descent along a tunnel during a naturally ventilated tunnel fire. A theoretical model is developed to predict the smoke depth below the ceiling along the tunnel. A series of numerical simulations of full-scale tunnel fires are conducted to compare with the developed model, and some coefficients such as the entrainment coefficient are determined from the simulation results. The concepts of critical moment and critical distance are proposed to characterize the smoke descent along the tunnel. The results show that as the smoke spreads longitudinally, the smoke depth below the tunnel ceiling continuously increases. The temperature decay along the tunnel due to heat losses and air entrainment at the smoke layer interface is considered as the main parameter for the smoke descent. After the vitiated air returns back to the fire source, the smoke stratification in the entire tunnel will be significantly reduced. The smoke layer depth along the tunnel based on the temperature distribution is relatively stable in the process of smoke development, which is not sensitive to the HRR, but influenced by the tunnel width, and this method could only be used before the critical moment. The outcomes of this study could provide references for a better understanding of smoke movement in naturally ventilated tunnels and provide technical guidelines for fire safety designers.
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