共查询到20条相似文献，搜索用时 15 毫秒
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Qingzhi An Qing Sun Andreas Weu David Becker‐Koch Fabian Paulus Sebastian Arndt Fabian Stuck A. Stephen K. Hashmi Nir Tessler Yana Vaynzof 《Liver Transplantation》2019,9(33)
Four π‐extended phosphoniumfluorene electrolytes (π‐PFEs) are introduced as hole‐blocking layers (HBL) in inverted architecture planar perovskite solar cells with the structure of ITO/PEDOT:PSS/MAPbI3/PCBM/HBL/Ag. The deep‐lying highest occupied molecular orbital energy level of the π‐PFEs effectively blocks holes, decreasing contact recombination. It is demonstrated that the incorporation of π‐PFEs introduces a dipole moment at the PCBM/Ag interface, resulting in significant enhancement of the built‐in potential of the device. This enhancement results in an increase in the open‐circuit voltage of the device by up to 120 mV, when compared to the commonly used bathocuproine HBL. The results are confirmed both experimentally and by numerical simulation. This work demonstrates that interfacial engineering of the transport layer/contact interface by small molecule electrolytes is a promising route to suppress nonradiative recombination in perovskite devices and compensates for a nonideal energetic alignment at the hole‐transport layer/perovskite interface. 相似文献
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Jun Peng The Duong Xianzhong Zhou Heping Shen Yiliang Wu Hemant Kumar Mulmudi Yimao Wan Dingyong Zhong Juntao Li Takuya Tsuzuki Klaus J. Weber Kylie R. Catchpole Thomas P. White 《Liver Transplantation》2017,7(4)
In addition to a good perovskite light absorbing layer, the hole and electron transport layers play a crucial role in achieving high‐efficiency perovskite solar cells. Here, a simple, one‐step, solution‐based method is introduced for fabricating high quality indium‐doped titanium oxide electron transport layers. It is shown that indium‐doping improves both the conductivity of the transport layer and the band alignment at the ETL/perovskite interface compared to pure TiO2, boosting the fill‐factor and voltage of perovskite cells. Using the optimized transport layers, a high steady‐state efficiency of 17.9% for CH3NH3PbI3‐based cells and 19.3% for Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3‐based cells is demonstrated, corresponding to absolute efficiency gains of 4.4% and 1.2% respectively compared to TiO2‐based control cells. In addition, a steady‐state efficiency of 16.6% for a semi‐transparent cell is reported and it is used to achieve a four‐terminal perovskite‐silicon tandem cell with a steady‐state efficiency of 24.5%. 相似文献
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Efficient conventional bulk heterojunction (BHJ) perovskite hybrid solar cells (pero‐HSCs) solution‐processed from a composite of CH3NH3PbI3 mixed with PC61BM ([6,6]‐phenyl‐C61‐butyric acid methyl ester), where CH3NH3PbI3 acts as the electron donor and PC61BM acts as the electron acceptor, are reported for the first time. The efficiency of 12.78% is twofold enhancement in comparison with the conventional planar heterojunction pero‐HSCs (6.90%) fabricated by pristine CH3NH3PbI3. The BHJ pero‐HSCs are further optimized by using PC61BM/TiO2 bi‐electron‐extraction‐layer (EEL), which are both solution‐processed and then followed with low‐temperature thermal annealing. Due to higher electrical conductivity of PC61BM over that of TiO2, an efficiency of 14.98%, the highest reported efficiency for the pero‐HSCs without incorporating high‐temperature‐processed mesoporous TiO2 and Al2O3 as the EEL and insulating scaffold, is observed from PC61BM modified BHJ pero‐HSCs. Thus, the findings provide a simple way to approach high efficiency low‐cost pero‐HSCs. 相似文献
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Polymer Solar Cells: Polymer Solar Cells with Efficiency >10% Enabled via a Facile Solution‐Processed Al‐Doped ZnO Electron Transporting Layer (Adv. Energy Mater. 12/2015) 
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下载免费PDF全文 Lethy Krishnan Jagadamma Mohammed Al‐Senani Abdulrahman El‐Labban Issam Gereige Guy O. Ngongang Ndjawa Jorge C. D. Faria Taesoo Kim Kui Zhao Federico Cruciani Dalaver H. Anjum Martyn A. McLachlan Pierre M. Beaujuge Aram Amassian 《Liver Transplantation》2015,5(12)
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Lethy Krishnan Jagadamma Mohammed Al‐Senani Abdulrahman El‐Labban Issam Gereige Guy O. Ngongang Ndjawa Jorge C. D. Faria Taesoo Kim Kui Zhao Federico Cruciani Dalaver H. Anjum Martyn A. McLachlan Pierre M. Beaujuge Aram Amassian 《Liver Transplantation》2015,5(12)
A facile and low‐temperature (125 °C) solution‐processed Al‐doped ZnO (AZO) buffer layer functioning very effectively as electron accepting/hole blocking layer for a wide range of polymer:fullerene bulk heterojunction systems, yielding power conversion efficiency in excess of 10% (8%) on glass (plastic) substrates is described. The ammonia‐treatment of the aqueous AZO nanoparticle solution produces compact, crystalline, and smooth thin films, which retain the aluminum doping, and eliminates/reduces the native defects by nitrogen incorporation, making them good electron transporters and energetically matched with the fullerene acceptor. It is demonstrated that highly efficient solar cells can be achieved without the need for additional surface chemical modifications of the buffer layer, which is a common requirement for many metal oxide buffer layers to yield efficient solar cells. Also highly efficient solar cells are achieved with thick AZO films (>50 nm), highlighting the suitability of this material for roll‐to‐roll coating. Preliminary results on the applicability of AZO as electron injection layer in F8BT‐based polymer light emitting diode are also presented. 相似文献
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Rakwon Kang Sujung Park Yun Kyung Jung Dong Chan Lim Myung Joo Cha Jung Hwa Seo Shinuk Cho 《Liver Transplantation》2018,8(10)
The tunnel junction (TJ) intermediate connection layer (ICL), which is the most critical component for high‐efficient tandem solar cell, generally consists of hole conducting layer and polyethyleneimine (PEI) polyelectrolyte. However, because of the nonconducting feature of pristine PEI, photocurrent is open‐restricted in ICL even with a little thick PEI layer. Here, high‐efficiency homo‐tandem solar cells are demonstrated with enhanced efficiency by introducing carbon quantum dot (CQD)‐doped PEI on TJ–ICL. The CQD‐doped PEI provides substantial dynamic advantages in the operation of both single‐junction solar cells and homo‐tandem solar cells. The inclusion of CQDs in the PEI layer leads to improved electron extraction property in single‐junction solar cells and better series connection in tandem solar cells. The highest efficient solar cell with CQD‐doped PEI layer in between indium tin oxide (ITO) and photoactive layer exhibits a maximum power conversion efficiency (PCE) of 9.49%, which represents a value nearly 10% higher than those of solar cells with pristine PEI layer. In the case of tandem solar cells, the highest performing tandem solar cell fabricated with C‐dot‐doped PEI layer in ICL yields a PCE of 12.13%; this value represents an ≈15% increase in the efficiency compared with tandem solar cells with a pristine PEI layer. 相似文献
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Highly crystalline conjugated polymers represent a key material for producing high‐performance thick‐active‐layer polymer solar cells (PSCs). However, despite their potential, a limited number of crystalline polymers are used in PSCs because of the lack of highly coplanar acceptor building blocks and insufficient light absorptivity (α < 105) of most donor (D)–acceptor (A)‐type polymers. This study reports a series of novel 3,7‐di(thiophen‐2‐yl)‐1,5‐naphthyridine‐2,6‐dione (NTDT) acceptor‐based conjugated polymers, PNTDT‐2T, PNTDT‐TT, and PNTDT‐2F2T, synthesized with 2,2′‐bithiophene (2T), thieno[3,2‐b]thiophene (TT), and 3,3′‐difluoro‐2,2′‐bithiophene (2F2T) donor units, respectively. PNTDT‐2F2T exhibits superior polymer crystallinity and a much higher absorption coefficient than those of PNTDT‐2T or PNTDT‐TT because of adequate matching between highly coplanar A (NTDT) and D (2F2T) building blocks. A bulk heterojunction solar cell based on PNTDT‐2F2T exhibits a power conversion efficiency of up to 9.63%, with a high short circuit current of 18.80 mA cm?2 and fill factor of 0.70, when a thick active layer (>200 nm) is used, without postfabrication hot processing. The findings demonstrate that the polymer crystallinity and absorption coefficient can be effectively controlled by selecting appropriate D and A building blocks, and that NTDT is a novel and versatile A building block for highly efficient thick‐active‐layer PSCs. 相似文献
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Victoria Vázquez‐Román José C. Utrilla José M. Fernández‐Santos Esperanza Conde Reyes Bernabé Consuelo Sampedro Inés Martín‐Lacave 《Journal of morphology》2013,274(7):725-732
The ultimobranchial follicles (UBFs) are considered embryonic remnants from the ultimobranchial body (UBB). They are follicular structures that vary in size and appearance depending on the age of the rat. The main objective of this article was to study the progressive changes in shape, size, and frequency of the UBFs in the postnatal rat, from birth to old‐age. To accomplish that objective, a systematic morphometric and incidental study of the UBF has been carried out in 110 Wistar rats of different ages and both sexes, divided into three groups: 1) young rats (5–90‐day‐old); 2) adult rats (6–15‐month‐old), and 3) old rats (18–24‐month‐old). The glands were serially sectioned and immunostained for calcitonin at five equidistant levels. According to our results, UBFs were observed in all thyroid glands but a more exhaustive sampling was occasionally necessary in male rats. In young rats, immature UBFs predominantly appeared whereas in adult rats, mature UBFs with cystic appearance and variable luminal content prevailed. We frequently found spontaneous anomalous UBFs in old rats, which we have termed as “ultimobranchial cystadenomata.” Additionally, in young rats, UBF areas significantly increased with age and they were larger when compared to that of normal thyroid follicles. Likewise, in adult rats, UBFs were significantly larger than normal thyroid follicles but only in female rats. In general, UBFs in females were also significantly larger than those found in male rats. Finally, all these differences related to UBFs together with a higher incidence in females of UB cystadenomata suggest a sexual dimorphism in regard to the destiny of these embryonic remnants during postnatal thyroid development. J. Morphol., 2013. © 2013 Wiley Periodicals, Inc. 相似文献
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Organic–inorganic halide perovskites are promising materials for next‐generation photovoltaic device due to their attractive photoelectrical properties such as strong light absorption, high carrier mobility, and tunable bandgap. Generally, perovskite solar cells require carrier transport layers (CTL) to provide a built‐in electric field and reduce the recombination rate. However, the construction of suitable electron‐ and hole‐transport layers is not cost effective, impairing the commercial application of the devices. An n–p perovskite homojunction absorber with a graded bandgap is developed by introducing a three‐step dynamic spin‐coating strategy and variable valence Sn elements. The bandgap of the perovskite absorber is gradually manipulated from 1.53 eV (the bottom) to 1.27 eV (the top). The electronic behavior is also transformed from n‐type (excess PbI2, the bottom) to p‐type (Sn vacancy, the top) in a very short distance (50 nm). This designed perovskite homojunction electronic structure not only expands the light harvesting range from 800 to 970 nm which provides potential to break the PCE limits, but also promotes oriented carrier transportation and weakens the dependence on CTL. The demonstrated asymmetrical active layer shows a brand‐new approach to simplify the device structure and boost the performance of CTL‐free perovskite solar cells. 相似文献
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Mathias Nyman Staffan Dahlström Oskar J. Sandberg Ronald Österbacka 《Liver Transplantation》2016,6(15)
Charge selective interlayers are of critical importance in order for solar cells based on low mobility materials, such as polymer‐fullerene blends, to perform well. Commonly used anode interlayers consist of high work function transition metal oxides, with molybdenum trioxide (MoO3) being arguably the most used. Here, it is shown that a thin interlayer of MoO3 causes unintentional bulk doping in solar cells based on polymers and polymer‐fullerene blends. The doping concentrations determined from capacitance–voltage measurements are larger than 1016 cm?3 and are seen to increase closer to the anode, reference devices without MoO3 are undoped. Using time of flight secondary ion mass spectroscopy it is furthermore shown that molybdenum is present on the surface of all films with an interfacial layer of MoO3 beneath the active layer. Doping concentrations of this magnitude are detrimental for device performance, especially for active layers >100 nm. 相似文献
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Summary Enzyme-deficient cell lines, lacking TK or HPRT and therefore unable to grow in HAT medium, may be used as feeder layers to
enhance clonal growth of wild-type cells. Low numbers of wild-type test cells may be plated in HAT medium with 5×105 HAT-sensitive feeder cells per Petri dish. The feeder cells remain attached and metabolizing for 1 to 2 weeks, but ultimately
die and detach, leaving colonies of test cells. This feeder layer technique is very simple and flexible and could have wide
applicability.
This work was a byproduct of a project on fusion and hybridization of marsupial and eutherian cells supported by the Australian
Research Grants Committee. 相似文献
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Minor workers of the ant Zacryptocerus pusillus have unusual exocrine secretions in both their mandibular and Dufour glands. The mandibular glands contain a 3:1 mixture of 4-heptanone and 4-heptanol, a mixture found only in the related species Z. varians. The Dufour gland contains a mixture of 13 aldehydes from C9 to C18, not previously encountered in ant secretions. The venom glands gave variable results with only nonanal present consistently. 相似文献