Effects of Alkyl Chain Length on the Optoelectronic Properties and Performance of Pyrrolo-Perylene Solar Cells

Liu, Xianqing,Kim, Yu Jin,Ha, Yeon Hee,Zhao, Qinghua,Park, Chan Eon,Kim, Yun-Hi American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.16

<P>While the impact of alkyl side-chain length on the photovoltaic properties of conjugated polymers and their performance in bulk heterojunction (BHJ) solar cells has been studied extensively, analogous studies on pyrrolo-perylene-based polymers have not received adequate attention. To explore these effects, we synthesized two copolymers based on <I>N</I>-annulated pyrrolo-perylene and consisting of cyano group substituents on thiophene vinylene thiophene units with two different alkyl groups of 2-decyltetradecyl and 7-decylnonadecyl, and we studied them with regard to chemical structure and photovoltaic performance. UV–vis spectroscopy and cyclic voltammetry studies showed that variations in alkyl chain length affect crystallization, light absorption, and the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. These factors have a pronounced impact on the morphology of BHJ thin films and their charge carrier separation and transportation characteristics, which, in turn, influences photovoltaic properties.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-16/acsami.5b01444/production/images/medium/am-2015-01444m_0008.gif'></P>

Expression and Characterization of a New L-amino Acid Oxidase AAO Producing α-ketoglutaric Acid from L-glutamic Acid

Rao Ben,Liao Xianqing,Liu Fang,Chen Wei,Zhou Ronghua,Ma Lixin,Wang YaPing 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.6

L-amino acid oxidase (AAO) was reported to be capable of converting L-glutamic acid to α-aketoglutaric acid (α-KG). The sequence of AAO from Kitasatospora cheerisanensis was synthesized based on Pichia pastoris codon-usage preferences. AAO gene was cloned into plasmid pPICZα which was transformed into P. pastoris. Next, multi-copy expression plasmids were constructed by using plasmid pHBM905BDM. High-density fermentation was performed and the recombinant enzyme was characterized. The conversion conditions were optimized. By using Escherichia coli expression system, no soluble or active AAO was obtained from two strains after fermentation and induction. We can’t obtain high-level expression of recombinant strains by using plasmid pPICZα. Therefore, we constructed multi-copy expression plasmids using plasmid pHBM905BDM. By using this plasmid, multi-copy strains were constructed and named as PAAO1, PAAO2, PAAO3, PAAO4, and PAAO5, respectively. The following results showed that expression of AAO in multicopy strains increased as designed and strain PAAO5 was chosen for high-density fermentation and enzyme activity experiments. After high-density fermentation, we achieved an AAO-expression yield of 120.8 U/mL. After temperature and pH optimization, the highest AAO activity was observed at a temperature and pH of 20°C and 6, respectively. After optimization of the conversion conditions, the average production rate of L-glutamic acid to α-KG was 3.46 g/L/h and the highest α-KG titer (103 g/L) was converted from 120 g/L L-glutamic acid. In this study, AAO was abundantly expressed by using P. pastoris expression system. The following experiments indicated that AAO is suitable for use in industrial applications.

High-level Expression of an Acidic and Thermostable Chitosanase in Pichia pastoris Using Multi-copy Expression Strains and High-celldensity Cultivation

Zhou Ronghua,Liao Xianqing,Liu Fang,Dong Qing,Chen Wei,Wang YaPing,Rao Ben 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.4

Chitin is a linear homopolymer of acetylated β- (1,4)-linked glucosamine residues and among the most abundant polysaccharides in the world. Here, we identified and purified a novel chitosanase (CCHA) from Aspergillus oryzae NKY2017 obtained from Hu’bei province in China. Construction of a cDNA library from this strain revealed the gene sequence subsequently expressed in Pichia pastoris and subsequent construction of multi-copy expression plasmids (CCHA1/2/3/4). The results demonstrated elevated levels of CCHA expression in multi-copy strains, with strain CCHA4 chosen for high-density fermentation and enzyme-activity experiments. High-density fermentation achieved a CCHA yield of 22,500 U/mL, and temperature and pH optimization resulted in the highest CCHA activity at 40°C and 4.0, respectively. We used this enzyme for a large-scale preparation of oligosaccharides: 4 g enzyme could convert 150 kg chitosan into oligosaccharides in 24 h at 40°C. These results demonstrated abundant CCHA expression in P. pastoris and suggested the efficacy of CCHA for use in industrial applications.

A high-performance solution-processed small molecule: alkylselenophene-substituted benzodithiophene organic solar cell

백장열,조철성,김명종,( Xianqing Liu ),박광훈,김유진,박찬언,김윤희 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

A solution-processed alkylselenophene-substituted benzodithiophene (BDT) small molecule, namely, BDTSe-TTPD, with broad absorption and suitable energy levels was synthesized. The widely used solvents o-dichlorobenzene (o-DCB), chlorobenzene (CB) or chloroform (CF) were used as the spin-coating solvent, to fabricate efficient photovoltaic devices with BDTSe-TTPD as the donor material and PC₇₁BM as the acceptor. Devices made from a CF solution demonstrated better performance in terms of short-circuit current, fill factor and power conversion efficiency, as compared to the devices made from the o-DCB and CB solutions. Finally, by optimizing the thickness of the active layer, a power conversion efficiency of 4.37% was achieved on devices with an area of 0.09 cm², under 100 mW cm² of simulated AM 1.5 irradiation.

Aerodynamic design and optimization of a high-loaded axial fan stage using a curvature control method

Jieling Li,Huanlong Chen,Yang Liu,Junli Wang,Xianqing Yang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.8

This study designs and optimizes a high-loaded transonic fan stage using a curvature control method. A fan stage with a total pressure ratio of 2.49 and adiabatic efficiency of over 87 % at the design point is obtained after 3D optimizations. The geometric curvature of the blade passage has important driving and adjusting effects on the mainstream and on the flow in the boundary layer. The reasonable optimization of camber line curvature can weaken the radial secondary flow on the blade surface and decrease shock losses effectively. It can also postpone or suppress boundary layer separation by reorganizing aerodynamic load. Hence, secondary flow losses are reduced, and the overall stall margin is expanded. This method features high precision, high operability, and short design cycle, hence providing highloaded fans/compressors with new freedom to improve design ability and offering new possibility to design system development.

Efficient Surface Display of L-glutamate Oxidase and L-amino Acid Oxidase on Pichia pastoris Using Multi-copy Expression Strains

Rao Ben,Zhou Ronghua,Dong Qing,Liao Xianqing,Liu Fang,Chen Wei,Liu Xiaoyan,Min Yong,Wang YaPing 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.4

L-glutamate oxidase (GLOD) and L-amino acid oxidase (AAO) were reported to be capable of convert L-glutamic acid to α-aketoglutaric acid (α-KG). These two enzymes gene have been successfully expressed by using pHBM905BDM in Pichia pastoris to produce α-aketoglutaric acid from L-glutamic acid in our previous studies. Here these two enzymes were displayed on P. pastoris to achieve the conversion. We constructed multi-copy expression plasmids using plasmid pHBM905BDM. By using this plasmid, multi-copy strains were constructed and named as PGLOD(1-3)-AGα1 and PAAO(1-3)-AGα1, respectively. The following results showed that expression of GLOD(1-3)- AGα1 and AAO(1-3)-AGα1 in multi-copy strains increased as designed and strain PGLOD3-AGα1 and PAAO3-AGα1 was chosen for high-density fermentation and enzyme activity experiments. By using a multi-copy expression approach and high-density fermentation, we achieved a GLOD expression yield of 688.5 U/g dry cell weight and AAO expression yield of 626.7 U/g dry cell weight. By using displayed GLOD, the average production rate of L-glutamic acid to α-KG was 6.22 g/L/h and the highest α-KG titer (124.5 g/L) was converted from 135 g/L L-glutamic acid. By using displayed AAO, the average production rate of L-glutamic acid to α-KG was 5.78 g/L/h and the highest α-KG titer (115.6 g/L) was converted from 135 g/L L-glutamic acid. It showed that displaying enzymes on P. pastoris are suitable for use in industrial applications.

A new high efficient alternating copolymer with properties of the bipolar for solar cells

Wu Xinwei,Yu Jin Kim,Xianqing Liu,Chan Eon Park,Yun-Hi Kim 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2