All-Automated Fabrication of Freestanding and Scalable Photo-Thermoelectric Devices with High Performance.

Flexible photo-thermoelectric (PTE) devices have great application prospects in the fields of solar energy conversion, ultrabroadband light detection, etc. A suitable manufacturing process to avoid the substrate effects as well as to create a narrow transition area between p-n modules for high-performance freestanding flexible PTE devices is highly desired. Herein, an automated laser fabrication (ALF) method is reported to construct the PTE devices with rylene-diimide-doped n-type single-walled carbon nanotube (SWCNT) films. The wet-compressing approach is developed to improve the thermoelectric power factors and figure of merit (ZT) of the SWCNT hybrid films. Then, the films are cut and patterned automatically to make PTE devices with various structures by the proposed ALF method. The freestanding PTE device with a narrow transition area of ≈2-3 µm between the p and n modules exhibits a high-power density of 0.32 µW cm-2 under the light of 200 mW cm-2, which is among the highest level for freestanding-film-based PTE devices. The results pave the way for the automatic production process of PTE devices for green power generation and ultrabroadband light detection.

Multifunctional Filler-Free PEDOT:PSS Hydrogels with Ultrahigh Electrical Conductivity Induced by Lewis-Acid-Promoted Ion Exchange.

Highly conductive hydrogels with biotissue-like mechanical properties are of great interest in the emerging field of hydrogel bioelectronics due to their good biocompatibility, deformability, and stability. Fully polymeric hydrogels may exhibit comparable Young's modulus to biotissues. However, most of these filler-free hydrogels have a low electrical conductivity of <10 S cm-1 , which limits their wide applications of them in digital circuits or bioelectronic devices. In this work, a series of metal-halides-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hydrogels with an ultrahigh electrical conductivity up to 547 S cm-1 is reported, which is 1.5 times to 104 times higher than previously reported filler-free polymeric hydrogels. Theoretical calculation demonstrated that the ion exchange between PEDOT:PSS and the metal halides played an important role to promote phase separation in the hydrogels, which thus leads to ultrahigh electrical conductivity. The high electrical conductivity resulted in multifunctional hydrogels with high performance in thermoelectrics, electromagnetic shielding, Joule heating, and sensing. Such flexible and stretchable hydrogels with ultrahigh electrical conductivity and stability upon various deformations are promising for soft bioelectronics devices and wearable electronics.

First pilot trial of colorectal ESD guided by a new magnetic anchor for ease of placement.

BACKGROUND: In recent years, studies have demonstrated that magnetic anchor-guided endoscopic submucosal dissection (MAG-ESD) is feasible and safe and may facilitate the treatment of all difficult lesions. However, the major problem with MAG-ESD is the inability to deliver the magnetic anchor to the gastrointestinal tract without withdrawal or reinsertion of the endoscope. Therefore, our team developed a magnetic anchor that could be easily inserted through the biopsy channel, facilitating ESD traction and evaluated its effectiveness and safety. METHODS: The study was conducted between October 2020 and June 2021 at The Second Affiliated Hospital of Harbin Medical University, China. One hundred and twelve patients with colorectal tumors treated with ESD were divided into two groups for historical control comparison. A channel-placed magnetic anchor (CPMAG) group and a control group consisting of patients who had conventional ESD without adjuvant traction. The rate of en bloc resection and resection with tumor-free lateral/basal margins (R0 resection), dissection speeds, procedure time, intraoperative bleeding and perforation complications, and postoperative follow-up were compared between the two groups, so as to evaluate the clinical effect and safety of the new magnetic anchor. RESULTS: The en bloc resection and R0 resection rate with CPMAG-ESD were slightly higher than with conventional ESD but this was not statistically significant. The median dissection speeds with CPMAG-ESD were higher than with conventional ESD, but the difference was not statistically significant. Intraoperative bleeding and postoperative complications with the CPMAG-ESD were less than with conventional ESD, but this was not statistically significant. The median operating time was shorter with CPMAG- ESD than with conventional ESD (24.5 min [range 15.8-66.5 min] vs 39 min [range 29-58 min], p = 0.024), and this difference was statistically significant. CONCLUSIONS: The new magnetic anchor-guided ESD technique appears to be a feasible and safe method for treating early colorectal tumors with en bloc resection, with improvement of the submucosal visual field, and less adverse events.

Ultra-High Electrical Conductivity in Filler-Free Polymeric Hydrogels Toward Thermoelectrics and Electromagnetic Interference Shielding.

Conducting hydrogels have attracted much attention for the emerging field of hydrogel bioelectronics, especially poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) based hydrogels, because of their great biocompatibility and stability. However, the electrical conductivities of hydrogels are often lower than 1 S cm-1 which are not suitable for digital circuits or applications in bioelectronics. Introducing conductive inorganic fillers into the hydrogels can improve their electrical conductivities. However, it may lead to compromises in compliance, biocompatibility, deformability, biodegradability, etc. Herein, a series of highly conductive ionic liquid (IL) doped PEDOT:PSS hydrogels without any conductive fillers is reported. These hydrogels exhibit high conductivities up to ≈305 S cm-1 , which is ≈8 times higher than the record of polymeric hydrogels without conductive fillers in literature. The high electrical conductivity results in enhanced areal thermoelectric output power for hydrogel-based thermoelectric devices, and high specific electromagnetic interference (EMI) shielding efficiency which is about an order in magnitude higher than that of state-of-the-art conductive hydrogels in literature. Furthermore, these stretchable (strain >30%) hydrogels exhibit fast self-healing, and shape/size-tunable properties, which are desirable for hydrogel bioelectronics and wearable organic devices. The results indicate that these highly conductive hydrogels are promising in applications such as sensing, thermoelectrics, EMI shielding, etc.