Synthesis and Photovoltaic Properties of Alternating Conjugated Polymers Derived from Thiophene-Benzothiadiazole Block and Fluorene/Indenofluorene Units

Jianfeng Li,Junfeng Tong,Peng Zhang,Chunyan Yang,Dejia Chen,Yuancheng Zhu,Yangjun Xia,Duowang Fan 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.2

A new donor-accepter-donor-accepter-donor (D-A-D-A-D) type 2,1,3-benzothiadiazole-thiophene-based acceptor unit 2,5-di(4-(5-bromo-4-octylthiophen-2-yl)-2,1,3-benzothiadiazol-7-yl)thiophene (DTBTTBr2) was synthesized. Copolymerized with fluorene and indeno[1,2-b]fluorene electron-rich moieties, two alternating narrow band gap (NBG) copolymers PF-DTBTT and PIF-DTBTT were prepared. And two copolymers exhibit broad and strong absorption in the range of 300-700 nm with optical band gap of about 1.75 eV. The highest occupied molecular orbital (HOMO) energy levels vary between –5.43 and –5.52 eV and the lowest unoccupied molecular orbital (LUMO) energy levels range from –3.64 to –3.77 eV. Potential applications of the copolymers as electron donor material and PC71BM ([6,6]-phenyl-C71 butyric acid methyl ester) as electron acceptors were investigated for photovoltaic solar cells (PSCs). Photovoltaic performances based on the blend of PF-DTBTT/PC71BM (w:w; 1:2) and PIF-DTBTT/PC71BM (w:w; 1:2) with devices configuration as ITO/ PEDOT: PSS/blend/Ca/Al, show an incident photon-to-current conversion efficiency (IPCE) of 2.34% and 2.56% with the open circuit voltage (Voc) of 0.87 V and 0.90 V, short circuit current density (Jsc) of 6.02 mA/ cm2 and 6.12 mA/cm2 under an AM1.5 simulator (100 mW/cm2). The photocurrent responses exhibit the onset wavelength extending up to 720 nm. These results indicate that the resulted narrow band gap copolymers are viable electron donor materials for polymer solar cells.

A New Anthracene-based Small Molecule as Cathode Interlayer for Efficient Polymer Solar Cells

Jianfeng Li,Chuang Zhao,Peng Zhang,Junfeng Tong,Chunyan Yang,Yangjun Xia,Duowang Fan 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.4

A new small molecule with excellent electron-transporting property, namely 9,10-bis(2-(N-octyl-1,8-naphthalimid-4-yl)ethynyl)anthracene (BNA), is prepared and characterized. A polymer solar cell (PSC) based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenylC61-butyricacidmethyl ester (PC61BM) is also fabricated by using BNA as the cathode buffer layer between the Al electrode and photoactive layer, and their influence on the performance of the PSCs is investigated. It is found that the open-circuit voltage (V oc ), short-circuit current density (J sc ), and power conversion efficiency (PCE) of a device with a 6-nm BNA layer improved to 0.63 V, 9.74 mA/cm2, and 3.74%, respectively, which correspond to an increase of 53.6%, 38.0%, and 177% compared to those without the buffer layer. The BNA buffer layer could effectively improve the interfacial contact performance between the Al electrode and photoactive layer, decrease the series resistance, and improve the collection efficiency of carriers. The devices with appropriate thickness of the BNA buffer layer can also replace the common low-work-function metal Ca for increasing the PCE and lifetime of PSCs.

Synthesis and Photovoltaic Properties of Alternating Conjugated Polymers Derived from Thiophene-Benzothiadiazole Block and Fluorene/Indenofluorene Units

Li, Jianfeng,Tong, Junfeng,Zhang, Peng,Yang, Chunyan,Chen, Dejia,Zhu, Yuancheng,Xia, Yangjun,Fan, Duowang Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.2

A new donor-accepter-donor-accepter-donor (D-A-D-A-D) type 2,1,3-benzothiadiazole-thiophene-based acceptor unit 2,5-di(4-(5-bromo-4-octylthiophen-2-yl)-2,1,3-benzothiadiazol-7-yl)thiophene ($DTBTTBr_2$) was synthesized. Copolymerized with fluorene and indeno[1,2-b]fluorene electron-rich moieties, two alternating narrow band gap (NBG) copolymers PF-DTBTT and PIF-DTBTT were prepared. And two copolymers exhibit broad and strong absorption in the range of 300-700 nm with optical band gap of about 1.75 eV. The highest occupied molecular orbital (HOMO) energy levels vary between -5.43 and -5.52 eV and the lowest unoccupied molecular orbital (LUMO) energy levels range from -3.64 to -3.77 eV. Potential applications of the copolymers as electron donor material and $PC_{71}BM$ ([6,6]-phenyl-$C_{71}$ butyric acid methyl ester) as electron acceptors were investigated for photovoltaic solar cells (PSCs). Photovoltaic performances based on the blend of PF-DTBTT/$PC_{71}BM$ (w:w; 1:2) and PIF-DTBTT/$PC_{71}BM$ (w:w; 1:2) with devices configuration as ITO/PEDOT: PSS/blend/Ca/Al, show an incident photon-to-current conversion efficiency (IPCE) of 2.34% and 2.56% with the open circuit voltage ($V_{oc}$) of 0.87 V and 0.90 V, short circuit current density ($J_{sc}$) of $6.02mA/cm^2$ and $6.12mA/cm^2$ under an AM1.5 simulator ($100mA/cm^2$). The photocurrent responses exhibit the onset wavelength extending up to 720 nm. These results indicate that the resulted narrow band gap copolymers are viable electron donor materials for polymer solar cells.

Power Monitor Networked Control Based on DeviceNet Field-bus

Zaiping Chen,Jianfeng Zhang,Chao Jia,Fan Wu 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this paper a networked monitor scheme with Powermonitor3000 monitor unit based on the DeviceNetfieldbus is proposed. We adopt SLC5/05 Controller produced by ROCKWELL Automation to controlPowermonitor3000 with DeviceNet fieldbus. Explicit Message mode, which is by M file communication mode, isutilized in this scheme for reading parameters, and this mode is the strongest DeviceNet communication mode. Thenetworked monitor scheme of Powermonitor3000 based on M file under DeviceNet is investigated. The procedure withPowermonitor3000 for online monitor electric transformer under DeviceNet fieldbus is introduced, which provides thereliable support for networked power distribution system and factory automation systems. The experimental results aregiven, in which the correctness and effectiveness of proposed scheme is verified.

Effects of the friction coefficient on the torque characteristics of a hydraulic cam-rotor vane motor

Qiankun Ma,Xuyong Wang,Fan Yuan,Liangshen Chen,Jianfeng Tao,Zhonghua Miao 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

The friction coefficient between the vane and the slot is one of the most critical factors that affects the performance of a continuous rotary hydraulic cam-rotor vane motor. To study the effects of this coefficient on the torque characteristics of the motor, the mathematical model for the normal force and the disturbing torque between the cam rotors and the vanes of the motor was established by analyzing the forces exerted on the vanes. The mathematical model was simulated with MATLAB, and simulation results show that an increase in the friction coefficient would simultaneously decrease the normal force and increase the disturbing torque, which would negatively affect the performance of the motor. Further experimental research indicated that the low-speed performance of the hydraulic cam-rotor motor was significantly improved when the friction coefficient was reduced by controlling the parallelism tolerance, flatness and roughness between the vanes and the slots.

Compressive Deformation Behavior of AZ31Mg Alloy Containing {10–12} Extension Twins at Different Temperature

Hua Zhang,Xiaoqing Bai,Minjian Hou,Lifei Wang,Qiang Zhang,Jianfeng Fan,Weiguo Li,Hongbiao Dong,Bingshe Xu 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

Influence of pre-introducing {10–12} extension twins on compressive deformation behavior of AZ31Mg alloy at differenttemperature was investigated. The compression tests were conducted along the normal direction of AZ31Mg alloy at roomtemperature, 100 °C, 200 °C and 300 °C with a strain rate of 1 × 10−3 s−1. The results indicated that the pre-introducing{10–12} extension twins strongly affected the yield strength, the peak strength and the strain hardening rate at middle-lowtemperature (≤ 200 °C). The twinned samples containing pre-introducing {10–12} extension twins exhibited smaller yieldstrength and larger peak strength than the as-received samples without {10–12} extension twins at temperature ≤ 200 °C. Forthe as-received samples, the strain hardening rate decreased gradually at different temperature. While for the twinned samples,the strain hardening behavior exhibited three distinct stages at temperature ≤ 200 °C. When compressing at 300 °C, the asreceivedand twinned samples exhibited similar compression flow curves and strain hardening rate curves. The continuousdynamic recrystallization (CDRX) was the main dynamic recrystallization (DRX) mechanism in the as-received sample whencompressing at 200 °C. The twin assisted DRX besides CDRX was also initiated in the twinned sample when compressingat 200 °C. While the DRX mechanism was transformed into the discontinuous dynamic recrystallization (DDRX) in boththe as-received and twinned samples when compressing at 300 °C.