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Jin F.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Jin F.,University of Chinese Academy of Sciences | Chu B.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Li W.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | And 15 more authors.
Organic Electronics: physics, materials, applications | Year: 2013

Authors demonstrated impact of series small ratio donors in C60 matrix on photovoltaic (PV) performance. A series of donor materials such as N′,N′-Di-1-naphthyl-N′,N′-diphenyl-1, 1′-biphenyl-4,4′-diamine (NPB), 4,-4′-Bis(carbazol-9-yl) (CBP), 4,4′,4″-tris(N-3-methylphenyl-N-phenyl-amine)triphenyl-amine (m-MTDATA), copper phthalocyanine (CuPc) and 4,4,4-tris(n-carbazolyl-triphenyl- amine) (TCTA) were blended with fullerene (C60) by different ratio. It was found that although donor-acceptor (DA) interface in planar heterojunction (PHJ) structure increased charge separation probability at the near interface section, the PV response was stronger for bulk heterojunction (BHJ) with low-ratio donor doping into C60 matrix in which exciton dissociation can take place immediately after photon absorption without a diffusion progress. The power conversion efficiency (PCE) of BHJ-PV cell based on NPB donor reaches 2.25%, which is double of that of the PHJ cell. In terms of our series results we obtained that ΔEHOMO (HOMO C60-HOMOdonor) between C60 acceptor and donors would provide a maximal influence on achievement of a maximal PCE and an optimal ΔEHOMO locates around 0.8 eV, which implies that dissociation of photo-exciton at C60 matrix needs feasible driving force. More detail mechanism was also argued. © 2013 Elsevier B.V. All rights reserved. Source


Yan X.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Yan X.,University of Chinese Academy of Sciences | Chu B.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Li W.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | And 15 more authors.
Organic Electronics: physics, materials, applications | Year: 2013

We have fabricated an improved organic photovoltaic (OPV) cell in which organic heterointerface layer is inserted between indium-tin-oxide (ITO) anode and copper-phthalocyanine (CuPc) donor layer in the conventional OPV cell of ITO/CuPc/fullerene (C60)/bathophenanthroline (Bphen)/Al to enhance the power conversion efficiency (PCE) and fill factor (FF). The inserted ITO-buffer layer consists of electron-transporting layer (ETL) and hole-transporting layer (HTL). We have changed the ETL and HTL materials variously and also changed their layer thickness variously. It is confirmed that ETL materials with higher LUMO level than the work function of ITO give low PCE and FF. All the double layer buffers give higher PCE than a single layer buffer of TAPC. The highest PCE of 1.67% and FF of 0.57% are obtained from an ITO buffer consisted of 3 nm thick ETL of hexadecafkluoro-copper-phthalocyanine (F16CuPc) and 3 nm thick HTL of 1,1-bis-(4-methyl-phenyl)- aminophenylcyclohexane (TAPC). This PCE is 1.64 times higher than PCE of the cell without ITO buffer and 2.98 times higher than PCE of the cell with single layer ITO buffer of TAPC. PCE is found to increase with increasing energy difference (ΔE) between the HOMO level of HTL and LUMO level of F 16CuPc in a range of ΔE < 0.6 eV. From the ΔE dependence of PCE, it is suggested that electrons moved from ITO to the LUMO level of the electron-transporting F16CuPc are recombined, at the F16CuPc/HTL-interface, with holes transported from CuPc to the HOMO level of HTL in the double layer ITO buffer ETL, leading to efficient extraction of holes photo-generated in CuPc donor layer. © 2013 Elsevier B.V. All rights reserved. Source


Zhao B.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Zhao B.,University of Chinese Academy of Sciences | Su Z.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Li W.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | And 14 more authors.
Nanoscale Research Letters | Year: 2013

We demonstrate high-efficient white organic light-emitting diodes (WOLEDs) based on triplet multiple quantum well (MQW) structure and focus on the influence on WOLEDs through employing different potential barrier materials to form type-I and type-II MQWs, respectively. It is found that type-I MQW structure WOLEDs based on 1,3,5-tris(N-phenyl-benzimidazol-2-yl)benzene as potential barrier layer (PBL) offers high electroluminescent (EL) performance. That is to say, maximum current efficiency and power efficiency are achieved at about 1,000 cd/m2 with 16.4 cd/A and 8.3 lm/W, which increase by 53.3% and 50.9% over traditional three-layer structure WOLEDs, respectively, and a maximum luminance of 17,700 cd/m2 is earned simultaneously. The achievement of high EL performance would be attributed to uniform distribution and better confinement of carriers within the emitting layer (EML). However, when 4,7-diphenyl-1,10-phenanthroline or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is used as PBL to form type-II MQW structure, poor EL performance is obtained. We attribute that to improper energy level alignment between the interface of EML/PBL, which leads to incomplete confinement and low recombination efficiency of carriers, a more detailed mechanism was argued. © 2013 Zhao et al.; licensee Springer. Source


Xia W.,CAS Institute of Mechanics | Li L.,Sinosteel Scie Technology Development Company Ltd | Wei Y.,CAS Institute of Mechanics | Zhao A.,University of Science and Technology Beijing | And 4 more authors.
Acta Mechanica Sinica/Lixue Xuebao | Year: 2015

Laser shock peening (LSP) is a widely used surface treatment technique that can effectively improve the fatigue life and impact toughness of metal parts. Cr5Mo1V steel exhibits a gradient hardened layer after a LSP process. A new method is proposed to estimate the impact toughness that considers the changing mechanical properties in the gradient hardened layer. Assuming a linearly gradient distribution of impact toughness, the parameters controlling the impact toughness of the gradient hardened layer were given. The influences of laser power densities and the number of laser shots on the impact toughness were investigated. The impact toughness of the laser peened layer improves compared with an untreated specimen, and the impact toughness increases with the laser power densities and decreases with the number of laser shots. Through the fracture morphology analysis by a scanning electron microscope, we established that the Cr5Mo1V steel was fractured by the cleavage fracture mechanism combined with a few dimples. The increase in the impact toughness of the material after LSP is observed because of the decreased dimension and increased fraction of the cleavage fracture in the gradient hardened layer. © 2015 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg Source


Liu J.-B.,China Petroleum Technology and Development Corporation | Li C.,China Petroleum Technology and Development Corporation | Qian J.-S.,China Petroleum Technology and Development Corporation | Xia Z.-W.,Zhejiang TPCO JIULI Composite Metals Co. | Pi H.-C.,Sinosteel Scie Technology Development Company Ltd
Suxing Gongcheng Xuebao/Journal of Plasticity Engineering | Year: 2016

A mechanical analysis for bimetal clad pipes under inner pressure is conducted in this paper. The bimetal clad pipes are composed of two kinds of metal with different Young's modulus. The relations between stress distribution, critical yield condition, elastic energy distribution and Young's modulus are studied. The results show that, under internal pressure, the circumferential stress is discontinuously distributed, and in practical application, additional tensile stress may occur at bimetallic interface position and cause cracking. © 2016, Editorial Board of Journal of Plasticity Engineering. All right reserved. Source

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