Ultrathin Silver Film Electrodes with Ultralow Optical and Electrical Losses for Flexible Organic Photovoltaics

Zhao, Guoqing,Shen, Wenfei,Jeong, Eunwook,Lee, Sang-Geul,Yu, Seung Min,Bae, Tae-Sung,Lee, Gun-Hwan,Han, Seung Zeon,Tang, Jianguo,Choi, Eun-Ae,Yun, Jungheum American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.32

<P>Improving the wetting ability of Ag on chemically heterogeneous oxides is technically important to fabricate ultrathin, continuous films that would facilitate the minimization of optical and electrical losses to develop qualified transparent Ag film electrodes in the state-of-the-art optoelectronic devices. This goal has yet to be attained, however, because conventional techniques to improve wetting of Ag based on heterogeneous metallic wetting layers are restricted by serious optical losses from wetting layers. Herein, we report on a simple and effective technique based on the partial oxidation of Ag nanoclusters in the early stages of Ag growth. This promotes the rapid evolution of the subsequently deposited pure Ag into a completely continuous layer on the ZnO substrate, as verified by experimental and numerical evidence. The improvement in the Ag wetting ability allows the development of a highly transparent, ultrathin (6 nm) Ag continuous film, exhibiting an average optical transmittance of 94% in the spectral range 400-800 nm and a sheet resistance of 12.5 Ω sq<SUP>-1</SUP>, which would be well-suited for application to an efficient front window electrode for flexible solar cell devices fabricated on polymer substrates.</P> [FIG OMISSION]</BR>

Nitrogen-Mediated Growth of Silver Nanocrystals to Form UltraThin, High-Purity Silver-Film Electrodes with Broad band Transparency for Solar Cells

Zhao, Guoqing,Shen, Wenfei,Jeong, Eunwook,Lee, Sang-Geul,Chung, Hee-Suk,Bae, Tae-Sung,Bae, Jong-Seong,Lee, Gun-Hwan,Tang, Jianguo,Yun, Jungheum American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.47

<P>Controlling the shape and crystallography of nanocrystals during the early growth stages of a noble metal layer is important because of its correlation with the final layer morphology and optoelectrical features, but this task is unattainable in vapor deposition processes dominated by artificially uncontrollable thermodynamic free energies. We report on experimental evidence for the controllable evolution of Ag nanocrystals as induced by the addition of nitrogen, presumed to be nonresidual in the Ag lattice given its strong float-out behavior. This atypical formation of energetically stable Ag nanocrystals with significantly improved wetting abilities on a chemically heterogeneous substrate promotes the development of an atomically flat, ultrathin, high-purity Ag layer with a thickness of only 5 nm. This facilitates the fabrication of Ag thin-film electrodes exhibiting highly enhanced optical transparency over a broad spectral range in the visible and near-infrared spectral range. An Ag thin-film electrode with a ZnO/Ag/ZnO configuration exhibits an average transmittance of about 95% in the spectral range of 400-800 nm with a maximum transmittance of over 98% at 580 nm, which is comparable with the best transparency values so far reported for transparent electrodes. This degree of optical transparency provides an excellent chance to improve the photon absorption of photovoltaic devices employing an Ag thin film as their window electrode. This is clearly confirmed by the superior performance of a flexible organic solar cell with a power conversion efficiency of 8.0%, which is far superior to that of the same solar cell using a conventional amorphous indium tin oxide electrode (6.4%).</P> [FIG OMISSION]</BR>

Redundancy Reduction for Compressed Sensing based Random Equivalent Sampling Signal Reconstruction

Jianguo Huang,Li Wang,Yijiu Zhao 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.5

Random equivalent sampling (RES) can composite a waveform with high equivalent sampling rate from multiple low speed sampling sequences. In practical application, the performance of RES signal reconstruction would be degraded by the non-uniform distribution of sampling time. Compressed sensing (CS) theory is adopted to reconstruct RES samples, which could mitigate the inherent coherence of sampling time. However, the CS reconstruction algorithm is sensitive to the signal sparsity level that is unknown in the reconstruction stage. In this paper, we propose a redundancy reduction algorithm for CS base RES signal reconstruction that can ensure reconstruction accuracy while reducing the number of random samples. The experimental results are reported to evaluate the performance of the proposed algorithm.

Static analysis of a radially retractable hybrid grid shell in the closed position

Jianguo Cai,Chao Jiang,Xiaowei Deng,Jianfeng Zhao,Yixiang Xu 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.6

A radially retractable roof structure based on the concept of the hybrid grid shell is proposed in this paper. The single-layer steel trusses of the radially foldable bar structure are diagonally stiffened by cables, which leads to a single-layer lattice shell with triangular mesh. Then comparison between the static behavior between the retractable hybrid grid shell and the corresponding foldable bar shell with quadrangular mesh is discussed. Moreover, the effects of different structural parameters, such as the rise-to-span ratio, the bar cross section area and the pre-stress of the cables, on the structural behaviors are investigated. The results show that prestressed cables can strengthen the foldable bar shell with quadrangular mesh. Higher structural stiffness is anticipated by introducing cables into the hybrid system. When the rise-span ratio is equal to 0.2, where the joint displacement reaches the minimal value, the structure shape of the hyrbid grid shell approaches the reasonable arch axis. The increase of the section of steel bars contributes a lot to the integrity stiffness of the structure. Increasing cable sections would enhance the structure stiffness, but it contributes little to axial forces in structural members. And the level of cable prestress has slight influence on the joint displacements and member forces.

Structural evaluation of a foldable cable-strut structure for kinematic roofs

Jianguo Cai,Qian Zhang,Yiqun Zhang,Daniel Sang-hoon Lee,Jianfeng Zhao 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.5

The rapidly decreasing natural resources and the global variation of the climate push us to find intelligent and efficient structural systems to provide more people with fewer resources. This paper proposed a kinematic cable-strut system to realize sustainable structures in responding to changing environmental conditions. At first, the concept of the kinematic system based on crystal-cell pyramid (CP) cable-strut unit was given. Then the deployment of the structure was studied experimentally. After that, the static behaviors in the fully deployed state under the symmetric and asymmetric load cases were investigated. Moreover, the effects of thermal loading and the initial prestress distribution were also discussed. Comparative studies between the proposed structure and other deployable cable-strut system under three times of design load cases were carried out. Finally, the robustness of the system was studied by removal of one passive cable at one time.

Spatial-Temporal Distribution of Soil Salt Crusts in the Taklimakan Desert Highway Shelterbelt of Northwest China

Jianguo Zhang,Xinwen Xu,Jiaqiang Lei,Ying Zhao,Shengyu Li 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Nonlinear stability analysis of a radially retractable hybrid grid shell in the closed position

Jianguo Cai,Qian Zhang,Youbao Jiang,Yixiang Xu,Jianfeng Zhao,Xiaowei Deng 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.24 No.3

The buckling capacity of a radially retractable hybrid grid shell in the closed position was investigated in this paper. The geometrically non-linear elastic buckling and elasto-plastic buckling analyses of the hybrid structure were carried out. A parametric study was done to investigate the effects rise-to-span ratio, beam section, area and pre-stress of cables, on the failure load. Also, the influence of the shape and scale of imperfections on the elasto-plastic buckling loads was discussed. The results show that the critical buckling load is reduced by taking account of material non-linearity. Furthermore, increasing the rise-tospan ratio or the cross-section area of steel beams notably improves the stability of the structure. However, the cross section area and pre-stress of cables pose negligible effect on the structural stability. It can also be found that the hybrid structure is highly sensitive to geometric imperfection which will considerably reduce the failure load. The proper shape and scale of the imperfection are also important.

Syntheses and Structures of Two Reduced Open-framework Titanophosphates

Zhao, Yongnan,Yu, Jianguo,Kwon, Young-Uk Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.4

Using metallic Ti powder as raw materials and 1,2-diaminocyclohexane (DACH) as the trial template, two novel reduced titanophosphate open-structures were hydrothermally isolated by varying the $H_3PO_4/H_2O$ ratio to adjust the pH value. TiPO-1 crystallizes in orthorhombic Pbca space group with cell parameters a = 21.956(3) $\AA$, b = 8.6268(11) $\AA$, c = 7.2883(9) $\AA$, V = 1380.5(3) $\AA^3$, Z = 4. TiPO-2 crystallizes in triclinic space group P$\bar{1}$ with parameters a = 5.1620(10) $\AA$, b = 8.815(2) $\AA$, c = 10.655(3) $\AA$, $\alpha$ = $99.45^{\circ}$, $\beta$ = $102.94^{\circ}$, $\gamma$ = $91.06^{\circ}$, V = 465.34 $\AA^3$. TiPO-1 is constructed by infinite -Ti-O-Ti-O- linkage that is capped by $PO_4$ groups to form a chain structure with protonated DACH molecules occupying the interchain spaces. TiPO-2 represents a rare 3-D reduced titanophosphate with 12-MR channels. The structure of TiPO-2 is a neutral framework with water molecules located in the channels.

Metagenomics analysis of the gut microbiome in healthy and bacterial pneumonia forest musk deer

Wei Zhao,Ziwei Ren,Yan Luo,Jianguo Cheng,Jie Wang,Yin Wang,Zexiao Yang,Xueping Yao,Zhijun Zhong,Wei Yang,Xi Wu 한국유전학회 2021 Genes & Genomics Vol.43 No.1

Background The forest musk deer (FMD, Moschus berezovskii) is an threatened species in China. Bacterial pneumonia was found to seriously restrict the development of FMD captive breeding. Historical evidence has demonstrated the relationship between immune system and intestinal Lactobacillus in FMD. Objective We sought to elucidate the diferences in the gut microbiota of healthy and bacterial pneumonia FMD. Methods The bacterial pneumonia FMD was demonstrated by bacterial and pathological diagnosis, and the gut microbiome of healthy and bacterial pneumonia FMD was sequenced and analysed. Results There are three pathogens (Pseudomonas aeruginosa, Streptococcus equinus and Trueperella pyogenes) isolated from the bacterial pneumonia FMD individuals. Compared with the healthy group, the abundance of Firmicutes and Proteobacteria in the pneumonia group was changed, and a high level of Proteobacteria was found in the pneumonia group. In addition, a higher abundance of Acinetobacter (p=0.01) was observed in the population of the pneumonia group compared with the healthy group. Several potentially harmful bacteria and disease-related KEGG subsystems were only found in the gut of the bacterial pneumonia group. Analysis of KEGG revealed that many genes related to type IV secretion system, type IV pilus, lipopolysaccharide export system, HTH-type transcriptional regulator/antitoxin MqsA, and ArsR family transcriptional regulator were signifcantly enriched in the metagenome of the bacterial pneumonia FMD. Conclusion Our results demonstrated that the gut microbiome was signifcantly altered in the bacterial pneumonia group. Overall, our research improves the understanding of the potential role of the gut microbiota in the FMD bacterial pneumonia.

Syntheses and Structures of Two Reduced Open-framework Titanophosphates

Yongnan Zhao*,권영욱,Jianguo Yu 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.4

Using metallic Ti powder as raw materials and 1,2-diaminocyclohexane (DACH) as the trial template, two novel reduced titanophosphate open-structures were hydrothermally isolated by varying the H3PO4/H2O ratio to adjust the pH value. TiPO-1 crystallizes in orthorhombic Pbca space group with cell parameters a = 21.956(3) , b = 8.6268(11) , c = 7.2883(9) , V = 1380.5(3) 3, Z = 4. TiPO-2 crystallizes in triclinic space group P with parameters a = 5.1620(10) , b = 8.815(2) , c = 10.655(3) , a = 99.45o, b = 102.94o, g = 91.06o, V = 465.34 3. TiPO-1 is constructed by infinite -Ti-O-Ti-O-linkage that is capped by PO4 groups to form a chain structure with protonated DACH molecules occupying the interchain spaces. TiPO-2 represents a rare 3-D reduced titanophosphate with 12-MR channels. The structure of TiPO-2 is a neutral framework with water molecules located in the channels.