Content of SPECIAL TOPIC—Organic and hybrid thermoelectrics in our journal

Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For selected: Download citations EndNote Ris BibTeX Toggle thumbnails Select Enhanced thermoelectric performance of PEDOT: PSS films via ionic liquid post-treatment Jiaji Yang(杨家霁), Xuejing Li(李雪晶), Yanhua Jia(贾艳华), Jiang Zhang(张弜), and Qinglin Jiang(蒋庆林) Chin. Phys. B, 2022, 31 (2): 027302.   DOI: 10.1088/1674-1056/ac2487 Abstract （438）   HTML （1）    PDF （1088KB）（160）       Knowledge map    Thermoelectric (TE) energy harvesting can effectively convert waste heat into electricity, which is a crucial technology to solve energy concerns. As a promising candidate for energy conversion, poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) has gained significant attention owing to its easy doping, high transparency, and solution processability. However, the TE performance of PEDOT:PSS still needs to be further enhanced. Herein, different approaches have been applied for tuning the TE properties:(i) direct dipping PEDOT:PSS thin films in ionic liquid; (ii) post-treatment of the films with concentrated sulfuric acid (H2SO4), and then dipping in ionic liquid. Besides, the same bis(trifluoromethanesulfonyl)amide (TFSI) anion and different cation salts, including 1-ethyl-3-methylimidazolium (EMIM+) and lithium (Li+), are selected to study the influence of varying cation types on the TE properties of PEDOT:PSS. The Seebeck coefficient and electrical conductivity of the PEDOT:PSS film treated with H2SO4EMIM:TFSI increase simultaneously, and the resulting maximum power factor is 46.7 μW·m-1·K-2, which may be attributed to the ionic liquid facilitating the rearrangement of the molecular chain of PEDOT. The work provides a reference for the development of organic films with high TE properties. Select Facile fabrication of highly flexible, porous PEDOT: PSS/SWCNTs films for thermoelectric applications Fu-Wei Liu(刘福伟), Fei Zhong(钟飞), Shi-Chao Wang(王世超), Wen-He Xie(谢文合), Xue Chen(陈雪), Ya-Ge Hu(胡亚歌), Yu-Ying Ge(葛钰莹), Yuan Gao(郜源), Lei Wang(王雷), and Zi-Qi Liang(梁子骐) Chin. Phys. B, 2022, 31 (2): 027303.   DOI: 10.1088/1674-1056/ac3502 Abstract （466）   HTML （1）    PDF （1976KB）（260）       Knowledge map    High-performance organic composite thermoelectric (TE) materials are considered as a promising alternative for harvesting heat energy. Herein, composite films of poly (3,4-ethyienedioxythiophene):poly(styrene sulfonate)/single-walled carbon nanotubes (PEDOT:PSS/SWCNTs) were fabricated by utilizing a convenient solution mixing method. Thereafter, the as-prepared hybrid films were treated using sulfuric acid (H2SO4) to further optimize the TE performance. Film morphological studies revealed that the sulfuric acid treated PEDOT:PSS/SWCNTs composite samples all possessed porous structures. Due to the successful fabrication of highly conductive networks, the porous nano-architecture also exhibited much more excellent TE properties when compared with the dense structure of the pristine samples. For the post-treated sample, a high power factor of 156.43 μW· m-1· K-2 can be achieved by adjusting the content of CNTs, which is approximately 3 orders of magnitude higher than that of the corresponding untreated samples (0.23 μW· m-1· K-2). Besides, the obtained films also showed excellent mechanical flexibility, owing to the porous nanostructure and the strong π-π interactions between the two components. This work indicates that the H2SO4 treatment could be a promising strategy for fabricating highly-flexible and porous PEDOT:PSS/SWCNTs films with high TE performances. Select Thermoelectric characteristics of flexible reduced graphene oxide/silver selenide nanowire composites prepared by a facile vacuum filtration process Zuo Xiao(肖佐), Yong Du(杜永), Qiufeng Meng(孟秋风), and Lei Wang(王磊) Chin. Phys. B, 2022, 31 (2): 028103.   DOI: 10.1088/1674-1056/ac447e Abstract （383）   HTML （0）    PDF （2384KB）（156）       Knowledge map    The reduced graphene oxide/silver selenide nanowire (rGO/Ag2Se NW) composite powders were fabricated via a wet chemical approach, and then flexible rGO/Ag2Se NW composite film was prepared by a facile vacuum filtration method combined with cold-pressing treatment. A highest power factor of 228.88 μW·m-1·K-2 was obtained at 331 K for the cold-pressed rGO/Ag2Se NW composite film with 0.01 wt% rGO. The rGO/Ag2Se NW composite film revealed superior flexibility as the power factor retained 94.62% after bending for 500 times with a bending radius of 4 mm, which might be due to the interwoven network structures of Ag2Se NWs and pliability of rGO as well as nylon membrane. These results demonstrated that the GO/Ag2Se NW composite film has a potential for preparation of flexible thermoelectric devices. Select Enhancing the thermoelectric performance through the mutual interaction between conjugated polyelectrolytes and single-walled carbon nanotubes Shuxun Wan(万树勋), Zhongming Chen(陈忠明), Liping Hao(郝丽苹), Shichao Wang(王世超), Benzhang Li(李本章), Xiao Li(黎潇), Chengjun Pan(潘成军), and Lei Wang(王雷) Chin. Phys. B, 2022, 31 (2): 028104.   DOI: 10.1088/1674-1056/ac48f9 Abstract （408）   HTML （4）    PDF （1723KB）（110）       Knowledge map    We present a method of constructing composites composed of conjugated polyelectrolytes (CPEs) and single-walled carbon nanotubes (SWCNTs) to obtain a high-performing flexible thermoelectric generator. In this approach, three kinds of polymers, namely, poly[(1,4-(2,5-didodecyloxybenzene)-alt-2,5-thiophene] (P1), poly[(1,4-(2,5-bis-sodium butoxysulfonate-phenylene)-alt-2,5-thiophene] (P2), and poly[(1,4-(2,5-bis-acid butoxysulfonic-phenylene)-alt-2,5-thiophene] (P3) are designed, synthesized and complexed with SWCNTs as thermoelectric composites. The electrical conductivities of the CPEs/SWCNTs (P2/SWCNTs, and P3/SWCNTs) nanocomposites are much higher than those of non-CPEs/SWCNTs (P1/SWCNTs) nanocomposites. Among them, the electrical conductivity of P2/SWCNTs with a ratio of 1:4 reaches 3686 S·cm-1, which is 12.4 times that of P1/SWCNTs at the same SWCNT mass ratio. Moreover, CPEs/SWCNTs composites (P2/SWCNTs) display remarkably improved thermoelectric properties with the highest power factor (PF) of 163 μW·m-1·K-2. In addition, a thermoelectric generator is fabricated with P2/SWCNTs composite films, and the output power and power density of this generator reach 1.37 μW and 1.4 W·m-2 (cross-section) at ΔT=70 K. This result is over three times that of the thermoelectric generator composed of non-CPEs/SWCNTs composite films (P1/SWCNTs, 0.37 μW). The remarkably improved electrical conductivities and thermoelectric properties of the CPEs/SWCNTs composites (P2/SWCNTs) are attributed to the enhanced interaction. This method for constructing CPEs/SWCNTs composites can be applied to produce thermoelectric materials and devices. Select N-type core-shell heterostructured Bi2S3@Bi nanorods/polyaniline hybrids for stretchable thermoelectric generator Lu Yang(杨璐), Chenghao Liu(刘程浩), Yalong Wang(王亚龙), Pengcheng Zhu(朱鹏程), Yao Wang(王瑶), and Yuan Deng(邓元) Chin. Phys. B, 2022, 31 (2): 028204.   DOI: 10.1088/1674-1056/ac272e Abstract （380）   HTML （1）    PDF （3324KB）（128）       Knowledge map    With the growing need on distributed power supply for portable electronics, energy harvesting from environment becomes a promising solution. Organic thermoelectric (TE) materials have advantages in intrinsic flexibility and low thermal conductivity, thus hold great prospect in applications as a flexible power generator from dissipated heat. Nevertheless, the weak electrical transport behaviors of organic TE materials have severely impeded their development. Moreover, compared with p-type organic TE materials, stable and high-performance n-type counterparts are more difficult to obtain. Here, we developed a n-type polyaniline-based hybrid with core-shell heterostructured Bi2S3@Bi nanorods as fillers, showing a Seebeck coefficient -159.4 μV/K at room temperature. Further, a couple of n/p legs from the PANI-based hybrids were integrated into an elastomer substrate forming a stretchable thermoelectric generator (TEG), whose function to output stable voltages responding to temperature differences has been demonstrated. The in situ output performance of the TEG under stretching could withstand up to 75% elongation, and stability test showed little degradation over a one-month period in the air. This study provides a promising strategy to develop stable and high thermopower organic TEGs harvesting heat from environment as long-term power supply. Select Donor-acceptor conjugated copolymer with high thermoelectric performance: A case study of the oxidation process within chemical doping Liangjun Chen(陈凉君), Wei Wang(王维), Shengqiang Xiao(肖生强), and Xinfeng Tang(唐新峰) Chin. Phys. B, 2022, 31 (2): 028507.   DOI: 10.1088/1674-1056/ac3504 Abstract （369）   HTML （3）    PDF （1377KB）（160）       Knowledge map    The doping process and thermoelectric properties of donor-acceptor (D-A) type copolymers are investigated with the representative poly([2,6'-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b] dithiophene]3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophenediyl)) (PTB7-Th). The PTB7-Th is doped by FeCl3 and only polarons are induced in its doped films. The results reveal that the electron-rich donor units within PTB7-Th lose electrons preferentially at the initial stage of the oxidation and then the acceptor units begin to be oxidized at a high doping concentration. The energy levels of polarons and the Fermi level of the doped PTB7-Th remain almost unchange with different doping levels. However, the morphology of the PTB7-Th films could be deteriorated as the doping levels are improved, which is one of the main reasons for the decrease of electrical conductivity at the later stage of doping. The best electrical conductivity and power factor are obtained to be 42.3 S·cm-1 and 33.9 μW·mK-2, respectively, in the doped PTB7-Th film at room temperature. The power factor is further improved to 38.3 μW·mK-2 at 75℃. This work may provide meaningful experience for development of D-A type thermoelectric copolymers and may further improve the doping efficiency.