bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Insight into D-a-Pi-a Featured Organic Sensitizers
Authors: Zhu Weihong 
Published: February 2020

The practical application of DSSCs requires further improvements in the power conversion efficiency and long term stability. Recently, we have systematically studied a novel concept of D−A−π−A model for the molecular engineering of organic photosensitizers. We highlights recent advance in the D−A−π−A based photosensitizers, specifically focusing on the mechanism of efficiency and stability enhancements. Also we take insight into the additional acceptor as well as the trade-off of long wavelength response. The basic principles are involved in the molecular engineering of efficient D−A−π−A sensitizers, providing a clear road map how to rationally extend the response wavelength, enhance molecular extinction coefficients, and step by step optimize photovoltaic efficiency.

Reference
s

(a) Y. Z. Wu, W. H. Zhu, Chem. Soc. Rev. 2013, 42, 2039–2058 (Review article); (b) Y. Z. Wu, W. H. Zhu, S. M. Zakeeruddin, M. Grätzel, ACS App
l.

Mat
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Interfaces
2015, 7, 9307−9318. (Spotlight on Applications).

(a) Y. S. Xie, Y. Y. Tang, W. J. Wu, Y. Q. Wang, J. C. Liu, X.Li, H. Tian, W. H. Zhu, J. Am. Chem. Soc.
2015, 137, 14055−14058; (b) Y. S. Xie, W. J. Wu, H. B. Zhu, J. C. Liu, W. W. Zhang, H. Tian, W. H. Zhu, Chem. Sci.
2015, DOI: 10.1039/C5SC02778K.

(a) W. H. Zhu, Y. Z. Wu, S. T. Wang, W. Q. Li, X. Li, J. Chen, Z.-S. Wang, H. Tian, Adv.
Funct. Mater.
2011, 21, 756–763; (b) Y. Z. Wu, X.Zhang, W. Q. Li, Z. S. Wang, H. Tian, W. H. Zhu, Adv. Energy Mater.
2012, 2, 149–156; (c) Y. Z. Wu, M. Marszalek, S. M. Zakeeruddin, Q. Zhang, H.Tian, M. Grätzel, W. H. Zhu, Energy Environ.
Sci.
2012, 5, 8261–8272; (d) W. Q. Li, Y. Z. Wu, X, Li, Y. S. Xie, W. H. Zhu, Energy Environ.
Sci.
2011, 4, 1830–1837.

(a) K. Pei, Y. Z. Wu, A. Islam, S. Q. Zhu, L. Y. Han, Z. Y. Geng, W. H. Zhu, J. Phys. Chem. C
2014, 118, 16552−16561; (b) H. B. Zhu, Y. Z. Wu, J. C. Liu, W. W. Zhang, W. J. Wu, W. H. Zhu, J. Mater. Chem. A, 2015,
3, 10603–10609; (c) Q. P. Chai, W. Q. Li, J. C. Liu, Z. Y. Geng, H. Tian, W. H. Zhu, Scientific Reports
2015, 5, 11330; (d) H. B. Zhu, B. Liu, J. C. Liu, W. W. Zhang, W. H. Zhu, J. Mater.
Chem. C
2015, 3, 6882−6890.

(a) Q. P. Chai, W. Q. Li, Y. Z. Wu, K. Pei, J. C. Liu, Z. Y. Geng, H. Tian, W. H. Zhu, ACS Appl. Mater. Interfaces
2014, 6, 14621–14630; (b) K. Pei, Y. Z. Wu, A. Islam, Q. Zhang, L. Y. Han, H. Tian, W. H. Zhu, ACS Appl. Mater. Interfaces
2013, 5, 4986–4995; (c) W. Q. Li, Y. Z. Wu, Q. Zhang, H. Tian, W. H. Zhu, ACS Appl. Mater. Interfaces
2012, 4, 1822−1830.
(Invited) Synthesis and Properties of Antiaromatic Porphyrins
Authors: Shinokubo Hiroshi 
Published: February 2020

Norcorrole is a ring-contracted porphyrin bearing 16π-electronic conjugation, of which synthesis has been quite challenging. Recently, we have succeeded to synthesize norcorrole Ni(II) complex 1 in over 90% yield from a dibromodipyrrin precursor via metal-templated strategy. We elucidated the planar structure and distinct antiaromatic nature of 1. Contrary to our expectation, meso-dimesitylnorcorrole Ni(II) 1 was quite stable under air at room temperature. The reactivity of 1 was also investigated. Although stable at room temperature, 1 was oxidized to 18π-aromatic oxacorrole under oxygen at 100 °C. In addition, the facile reduction and oxidation reaction of 1was applied to fabricate rechargeable batteries, which exhibited excellent charge/discharge capacity and durability.
We have also prepared N,N’-dihydrodiazaporphyrins 2 through chemo- and regioselective reduction of diazaporphyrins. The structure and properties of this novel porphyrinoids have been investigated. N,N’-dihydrodiazaporphyrins 2 was found to be antiaromatic because of their 20π-conjugation including lone pairs on nitrogen atoms and their highly planar structures.

Figure 1
(Invited) Design of High NIR Emissive Lanthanide Porphyrinoids
Authors: Zhang Jun-Long , Hu Ji-Yun , Ning Ying-Ying 
Published: February 2020

Lanthanide (Ln) complexes have been widely used in biological imaging and functional materials due to their attractive optoelectronic and magnetic properties. Strongly absorbing ligand scaffolds such as conjugated macrocycles are of great interest for Ln complex construction, for the maintaining solution stability, preventing coordination of quenching moieties and serving as antennas.1 Porpholactones, in which one porphyrin b,b′-double bond replaced by a lactone moiety, could be potent candidate to further increase NIR emission of lanthanides.2,3 In this talk, we will report the synthesis and characterization of a series of Ln porpholactones as well as their photophysical properties. The lactonization of beta-periphery of porphyrins renders the lower triplate excited states compared to those in porphyrins, which enhances the NIR emission of Ln ions.4 More importantly, through beta-fluorination of porphyrin periphery, the life time of NIR emission is significantly increased, which is considered to block the non-irradtive pathway. Taken together, the beta-modification of porphyrin represent an effective approach to enhance the NIR emission of Ln ions, which has the potential to further improve the practical application of Lanthanide chemistry.4
References:
1. V. Bulach, F. Sguerra, M. W. Hosseini, Coord. Chem. Rev. 2012, 256, 1468–1478;
2. Xian-Sheng Ke, Hongmei Zhao, Xiaoran Zou, Yingying Ning, Xin Cheng, Hongmei Su*, and Jun-Long Zhang* ,J. Am. Chem. Soc., 2015, 137, 10745-10752
3. Xian-Sheng Ke, Yi Chang, Jia-Zhen Chen, Jiangwei Tian, John Mack, Xin Cheng, Zhen Shen* and Jun-Long Zhang*, J. Am. Chem. Soc., 2014, 136, 9598-9607;
4. Xian-Sheng Ke, Bo-Yan Yang, Xin Cheng, Sharon Lai-Fung Chan, and Jun-Long Zhang*, Chem. Eur. J., 2014, 20, 4324-4333;
5. Data unpublished.

Figure 1
(Invited) Porphyrins Based Gas Sensors and Their Applications
Authors: Di Natale Corrado , Paolesse Roberto 
Published: February 2020

The role of porphyrins in life processes is well known. Iron complexes for instance are prostetic groups of important proteins such as hemoglobine and cytochromes. On the other hand, reduced porphyrins, as magnesium chlorin complexes, are fundamental in the photosynthetic processes. Such richness of properties is particularly attractive for chemical sensing. The molecular framework of porphyrins is a unique site for a wide range of interaction mechanisms useful for analyte binding. the interactions span from Van der Waals forces to hydrogen bond, to π interactions and to the coordination to the central metal ion.
The concurrence of all these mechanisms makes difficult the development of selective sensors, even if selectivity can in some cases found or improved by a suitable design of the sensor. On the other hand, the sensitivity of porphyrins can be oriented, through a proper molecular design, towards different classes of analytes. This control is of great value for the design of sensor arrays where several sensors non-selective but different among them are considered together.
We have been interested since about two decades to the use porphyrins to develop sensors for volatile compounds and gases. The physical properties of porphyrins restrict the transduction mechanisms that can be exploited to create an electric signal from the porphyrin-analyte interaction. It is important to recall that a chemical sensor actually measures a physical quantity of the sensing material that is affected by the interaction with the analyte.
We developed sensors measuring the mass, the optical absorbance, the surface potential and the charge transferred either to or from an inorganic semiconductor.
The sensing properties in all these devices can be related to the properties of the individual porphyrins, for instance the Hard and Soft Acids and Bases (HSAB) Pearson’s rule can be invoked to elucidate the sensitivity of porphyrins coated quartz microbalance sensors with regards to amines and alcohols.
In this paper, we will provide a rationale for the development of porphyrins based gas sensors discussing the pros and the cons of each transduction principle. A review of the applications will also be illustrated with a special emphasis on medical diagnosis through the analysis of volatile compounds.
Effect of Gases during Pyrolysis on Physical and Electrochemical Properties of SU-8 Photoresist Derived Carbon Film
Authors: Abd Hamid Sharifah Bee , Lee pui Kee , Ibrahim Fatimah , Madou Marc J 
Published: February 2020

In this study, the effect of type of gases used in pyrolysis on the physical and electrochemical characteristic on SU-8 photoresist derived carbon film fabricated on silicon wafer was been investigated. Pyrolysis process was performed in the presence of nitrogen, argon and helium gas, repectively in temperature of 1100 °C in furnace. Thermogravimetric analysis, Raman spectroscopy, X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy techniques were used to charcterise the surface structure of fabricated carbon film. The electrochemical properties of the SU-8 fabricated thin film was analysed with cyclic voltammetry and electrochemical impedance spectroscopy. The results were then correlated with type of gases in pyrolysis process.
Acknowledgement
This research is supported by University Malaya Flagship Grant project FL001A-14AET, and Transdisciplinary Research Grant Scheme (TRGS TR002A-2014) from Malaysian Ministry of Higher Education, and MOSTI SF020-2014.
Fabrication of Biocompatible Hollow Microneedles Using the C-MEMS Process for Transdermal Drug Delivery
Authors: Pramanick Bidhan , Martinez-Chapa Sergio Omar , Madou Marc J 
Published: February 2020

Microneedles are important component for the local delivery of drug with precise dose in controlled release to overcome the over dosage problem and decrease side-effects in drugs. These have been identified as a transformative technology for a painless, self-administered alternative to hypodermic injection and solid microneedles have been marketed for a many applications including scar treatment and improving skin permeability of topical drug formulations. Hollow microneedles have the potential to offer a large advantage in performance over these solid microneedle architectures. The architecture of hollow microneedle is more flexible and allows for delivery of larger drug molecules and volumes than other microneedle architectures. By integrating the hollow microneedles with micropumps, these can facilitate active control over the drug delivery profile to allow for continuous drug release for the applications such as insulin delivery. However the complications in the fabrication process are limiting towards future development of hollow microneedle platforms. A variety of microfabrication technologies have been developed for microneedles. The primary approaches for fabricating hollow microneedles have motivated on top-down approaches using the materials such as silicon, metal, or glass. However, the requirement to fabricate a hollow microneedle creates a substantial fabrication challenge for top-down approaches.
We present here a novel method for fabricating hollow microneedles using Carbon-MEMS (C-MEMS) process. C-MEMS process is getting more attention since last 15 years for its low cost, reliability and simplicity in the process. The high aspect ratio carbon hollow microneedle structures are fabricated in two steps: fabrication of SU8 microneedles in one step photolithography and conversion of polymer structures to carbon in pyrolysis process. The ease of fabrication of high aspect ratio SU8 structure makes it a suitable candidate for microneedle application. We report here for the very first time the hollow microneedle with glassy-carbon nature which is biocompatible. The percentage of shrinkage of SU8 structures after pyrolysis is also reported in this work. The outer diameter shrinkage is around 42% for 200µm tall needle where the inner and outer diameter ratios are 1/5, 1/3, 1/2 and it is 34.92% for solid needle structure. The inner diameter is also shrunk for all the cases. However, the outer diameter is shrunk only around 15% when the ratio of inner and outer diameter is 2/3 and the inner diameter is expanded in this case. The integration of these needle structures with drug delivery system (micropump) is our ongoing work.

Figure 1
SU-8/MWCNT derived Electrospun Composite Carbon Nanofabric as a High Performance Anode Material for Lithium Ion Battery
Authors: Kakunuri Manohar , Kaushik Shubham , Saini Ayush , Sharma Chandra Shekhar 
Published: February 2020

Introduction

Carbon nanofibers (CNFs) have drawn a great attention for being used as anode materials for lithium ion battery due to short lithium ion transport distances, high resilience to volume expansion during cycling even at high current densities and enhanced electronic conductivity (1). Electrospinning is a promising and scalable method for preparing continuous nanofibers. Among wide range of electrospun polymer fibbers high carbon yield polyacrylonitrile (PAN) derived carbon nanofibers were well studied for Li-ion battery application (2, 3).
In this work, we have synthesized SU-8/CNT composite carbon nanofibers web over stainless steel current collector. Thus prepared composite carbon nanofiber web was tested for lithium ion intercalation. Electrochemical performance of composite fibers was compared with SU-8 derived carbon fiber web and SU-8 derived carbon thin film (4).

Experimental

0.5% multi walled carbon nanotubes (MWCNTs) were dispersed into SU-8 (2015) photoresist solution using probe sonication for 30 min. Electrospun composite nanofiber web was prepared by modified C-MEMS process to keep morphology intact during the baking and pyrolysis. Galvanostatic charge discharge experiments were performed at different C-rates using Li metal as reference electrode.

Results and discussions:

SU-8/CNT composite carbon nanofibers morphology was investigated by scanning electron microscopy. FESEM images of nanofibers before and after pyrolysis were shown in Fig. 1a and 1b. Electrochemical performance of these carbon fibers was studied at different current densities form 0.1 to 1 C as shown in Figure 1c. Initial reversible specific capacity found to be 1317 mAh/g for SU-8/CNT composite carbon fiber web at 0.1 C. This specific capacity value is far better than reversible capacity values of SU-8 derived carbon films (~385 mAh/g) and other electrospun carbon nanofibers. Furthermore these CNFs web shown very good cyclic performance at higher C-rates. Specific reversible capacity at 1C rate (372 mA/g) was found to be 516 mAh/g. This performance can be ascribed to tolerance of expansion and shrinkage during lithium insertion and de-insertion and enhanced electronic conductivity due to CNTs presence during the pyrolysis. Detailed comparison of electrochemical performance of composite fibers with photoresist derived carbon thin films and other carbon nanofibers will be presented during the conference.

References:

S. L. Candelaria, Y. Shao, W. Zhou, X. Li, J. Xiao, J. G. Zhang, Y. Wang, J. Liu, J. Li, G. Cao, Nano Energy, 1, 195 (2012).

X. Mao, T. A. Hatton, G. C. Rutledge, Curr. Org. Chem., 17, 1390 (2013).

J. K. Lee, K. Wan, J. B. Ju, B. W. Cho, W. II. Cho, D. Park, K. S. Yun, Carbon, 39, 1299 (2001).

M. Kakunuri, C. S. Sharma, ECS Trans., 61, 37(2014).

Figure 1
Investigation on the Conversion Reaction Voltage and Reversibility of CuF2 Electrode in Li-Ion Battery
Authors: Seo Joon Kyo , Cho Hyung-Man , Sina Mahsa , Takahara Katsunori , Chapman Karena W , Borkiewicz Olaf J , Meng Ying Shirley 
Published: February 2020

Li-ion conversion materials have a higher theoretical capacity than commercialized intercalation compounds.[1] During the conversion reaction, more than one electron are used per transition metal ion, which is promising energy storage compared to one-electron reaction of intercalation compounds. Among conversion materials, transition metal difluorides, MF2 (M=Fe, Ni and Cu), have a relatively higher theoretical reaction voltage (2.66, 2.96 and 3.55 V vs. Li/Li+).[2,3] The voltage discrepancy, however, is a well known issue on transition metal difluorides. The experimental voltage is lower than thermodynamically derived theoretical voltage.[4] In this study, we develop the formalism of conversion reaction voltage as a function of size of metal nanoparticle formed during the lithiation. Density functional theory (DFT) calculation shows that the conversion reaction voltage depends on the size of a metal nanoparticle generated. We take annual dark field-scanning transmission electron microscopy (ADF-STEM) on the lithiated CuF2 and NiF2 cell, which demonstrates the formation of Cu and Ni nanoparticles with average sizes of ~ 2.5 and 1.5 nm, respectively. Near-equilibrium potentiostatic intermittent titration technique (PITT) is conducted to display the lower voltage with respect to a thermodynamic voltage. We find that the surface energy of metal nanoparticles leads to lower voltage relative to the thermodynamic voltage.
In addition, we develop a reversible CuF2 for the first time by coating NiO. Electron energy loss spectroscopy (EELS) elemental maps prove that the lithiation process mostly occurs in high NiO domain. We propose NiO as an artificial solid electrolyte interphase, which alleviates Cu dissolution during the conversion reaction.

Figure 1
A New and Facile Method to Improve the Electrochemical Performance of Si Anode: Ultrathin Polydopamine Coating upon Conductive Carbon Particles
Authors: Song Danoh , Jung Dae Soo , Choi Jaecheol , Kong Seokhyeon , Ryou Myung-Hyun , Lee Yong Min 
Published: February 2020

Si-based active materials started to be used for small lithium-ion batteries (LIBs) such as 18650 cells with 3.5Ah (INR18650MJ1) in 2015 by LG Chem. However, its relative amount is known to be much smaller than graphitic materials due to the continuous pulverization caused by large volume change during cycling. The gas generation originated from electrolyte decomposition could lead to fast capacity decay of LIB cells. However, regardless of lots of trials such as how to construct nanostructured Si particles and design new adhesive binders, more efficient methods still have to be devised extensively. In this study, we are interested in modifying the surface property of conductive carbon materials, because they have relatively high volume ratio within the electrode and lots of contact points with Si particles. In addition, if there are some crosslinkable moieties upon the conductive carbons, all the Si particles will be well maintained electrochemically active within the electrode.
Based on these strategies, we tried to coat the polydopamine (PD) upon conductive carbons, Super-P, as thin as possible not to impede their electrical conduction. The prepared PD-coated Super-P (PD-SP) was well dispersed even within the aqueous medium. In particular, when polyacrylic acid (PAA) as a polymeric binder is introduced into aqueous anode slurry, the amine group in PD-SP and the hydroxyl group in PAA can react to form the crosslinking bonds. From the adhesion strength measurements by the surface and interfacial cutting analysis system (SAICAS) tool, we could find the increased adhesion properties. As a result, the cycle performance of Si anode was greatly improved to deliver about 1000 mAh/g after 1000 cycles even at 1.2 A/g.
Acknowledges
This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977) and the Energy Efficiency & Resources Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20142010102980).
Highly Porous Electrospun ZnCo2O4 Nanofibers for Lithium Ion Battery Electrodes
Authors: Kim Jae-Chan , Kim Da-Sol , Yeo In-Hyeong , Kim Dong-Wan 
Published: February 2020

Lithium ion batteries have been widely used in a variety of fields such as electric vehicles, portable electronic devides, and large scale energy storage systems. In order to fullfill the stringent industrial requirements in these fields, novel electrode materials should be developed providing high electrochemical performances (high energy density and high power density). Transition metal oxides (TMO) are possible candidate materials to satisfy requirements of next generation anodes due to their high theoretical capacities. Among TMO materials, spinel Co3O4 which is a typical Li-conversion reaction material, represents the high specific capacity and reversibility. In addition, binary TMO such as NiCo2O4, CoMn2O4, MnCo2O4, and ZnCo2O4 have been suggested as novel high-capacity anode materials. Especially, ZnCo2O4 has the high theoretical capcity of 975 mAh/g based on both Li-alloying and –conversion reactions.
The nanostructuring of electrode materials is a key enabling factor to improve their electrochemical properties. An electrospinning process is the simple and versatile way to fabricate one dimensional fibrous nanostrcutured electrodes. In this study, we fabricated highly porous ZnCo2O4 nanofibers (P-ZnCo2O4 NFs) using simple electrospinning of ZnCo2O4/ZnO nanofibers by controlling the ratio of Zn to Co and selevtive etching of ZnO. Firstly, ZnCo2O4/ZnO nanofibers were fabricated by electrospinning and subsequent two-step heating processes. Zn and Co nitrate precursors with different Zn/Co ratios were completely dissolved in dimethyl formamide (DMF) containing Polyacrylronitrile. The mixed solution was loaded into a plastic syringe and metal-containing polymeric fibers were produced by appling a voltage of 15 kV to the nozzle. Then, the as-spun ZnCo2O4/ZnO nanofibers were stabilized in air to 280°C for 6 h and heated in Ar at 600°C for 2 h. For selective etching the excess ZnO, the ZnCo2O4/ZnO nanofibers were soaked in KOH solution. Finally, highly porous ZnCo2O4 nanofibers were obtained.
The fabricated P-ZnCo2O4 NFs with the diameter of ~120 nm provided large surface area and porosity by the selective etching of ZnO phase. Furthermore, P-ZnCo2O4 NFs exhibited enhanced electrochemical properties due to porous nature offering large contact area with electrolyte, efficient electron pathway, and short Li ion diffusion length.