Achieving Free-Standing PEDOT:PSS Solar Generators with Efficient All-in-One Photothermoelectric Conversion

Removal of protonic doping from PEDOT:PSS by weak base for improving aluminum solid electrolytic capacitor performance

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a promising conductive polymer material, but its acidic nature leads to device deterioration and poor long-term durability. It is usual practice to neutralise PEDOT:PSS solutions with bases, resulting in a decrease of conductivity. The causes of the decline in conductivity remain disputed and uncertain. In this study, three bases (sodium hydroxide, ammonium hydroxide, and imidazole) were employed to treat PEDOT:PSS to investigate their effects on doping level, composition, and structure. The results show that bases may dedope PEDOT:PSS by removing the proton doping from the PEDOT chain. Meanwhile, insulating PSS is removed, and the aggregated structure is optimised to ensure that conductivity is not significantly reduced. The PEDOT:PSS treated with the weak base imidazole showed the least loss of conductivity due to only a modest decrease in doping level and the greatest loss of insulating PSS. Aluminium electrolytic capacitors made using imidazole pH-adjusted solutions have a capacitance ratio of up to 98.28% and an equivalent series resistance of 26 mΩ. These findings provide a valuable reference for developing high electrical characteristics and neutral PEDOT:PSS materials.

High power output density organic thermoelectric devices for practical applications in waste heat harvesting

Organic thermoelectric (TE) materials are of great interest for researchers in waste heat recovery, especially for waste heat harvesting at near room temperature. Significant progress has been achieved in terms of their figure of merit (zT) values recently, which has presented new insights into the development of organic TE materials. For numerous practical applications of thermoelectric generators, where waste heat is unlimited and cost negligible, the primary goal has been switched to achieve high power output density rather than improving their heat-to-electricity conversion efficiency. In this review, we first discussed the theoretical relationship between the thermoelectric properties of organic materials and the power output density of devices. Then, we analyzed the state-of-the-art strategies for improving the power factor of organic materials. Methods for modulating the structure of the TE legs were discussed with an aim to maintain the temperature difference between the hot side and the cold side of the devices. Finally, some representative devices were summarized for the potential applications of the TEGs along with an outlook on the future of organic thermoelectric materials and devices.

Recent Advances in the Tunable Optoelectromagnetic Properties of PEDOTs

Conducting polymers represent a crucial class of functional materials with widespread applications in diverse fields. Among these, poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives have garnered significant attention due to their distinctive optical, electronic, and magnetic properties, as well as their exceptional tunability. These properties often exhibit intricate interdependencies, manifesting as synergistic, concomitant, or antagonistic relationships. In optics, PEDOTs are renowned for their high transparency and unique photoelectric responses. From an electrical perspective, they display exceptional conductivity, thermoelectric, and piezoelectric performance, along with notable electrochemical activity and stability, enabling a wide array of electronic applications. In terms of magnetic properties, PEDOTs demonstrate outstanding electromagnetic shielding efficiency and microwave absorption capabilities. Moreover, these properties can be precisely tailored through molecular structure modifications, chemical doping, and composite formation to suit various application requirements. This review systematically examines the mechanisms underlying the optoelectromagnetic properties of PEDOTs, highlights their tunability, and outlines prospective research directions. By providing critical theoretical insights and technical references, this review aims to advance the application landscape of PEDOTs.

A solar thermoelectric system by temperature difference for efficient removal of chromium (VI) in water and soil

In this work, we designed and developed a facile solar thermoelectric generator (STEG)-based system and a new electrokinetic remediation (EKR) system, which consists of main electrodes and unenergized auxiliary electrodes. The prepared nanocomposite was investigated for the effectiveness of the STEG+PANI-CNT/GF system in remediating Cr-contaminated. Photothermal performance test were applied in order to examine this STEG could export a power density of 365.56 mW/dm2 and output potential of 801 mV at the temperature difference of 50 ℃. Thus the STEG could be used as the power to construct a Cr(VI) removal system using polyaniline (PANI) film/carbon nanotubes (CNT) modified graphite felt (GF) electrode (PANI-CNT/GF) as cathode and graphite rod as anode. The as-prepared STEG+PANI-CNT/GF system exhibited a significant Cr(VI) removal efficiency (96.2 % in water) through electromigration, electro-adsorption and electroreduction. Moreover, a multi auxiliary electrodes (AEs) system (STEG+PANI-CNT/GF+AEs) with six PANI-CNT/GF auxiliary electrodes was constructed in remediating Cr(VI)-contaminated soil, showing Cr(VI) removal efficiency of 16.7-60.1 % higher than that of STEG+PANI-CNT/GF. The PANI-CNT/GF auxiliary electrodes could bind Cr(VI) and adjust electric field distribution, contributing to adsorption and reduction of Cr(VI). Consequently, this work provides a promoting approach for heavy metals removal in future application.

Progress on Material Design and Device Fabrication via Coupling Photothermal Effect with Thermoelectric Effect

Recovery and utilization of low-grade thermal energy is a topic of universal importance in today's society. Photothermal conversion materials can convert light energy into heat energy, which can now be used in cancer treatment, seawater purification, etc., while thermoelectric materials can convert heat energy into electricity, which can now be used in flexible electronics, localized cooling, and sensors. Photothermoelectrics based on the photothermal effect and the Seebeck effect provide suitable solutions for the development of clean energy and energy harvesting. The aim of this paper is to provide an overview of recent developments in photothermal, thermoelectric, and, most importantly, photothermal-thermoelectric coupling materials. First, the research progress and applications of photothermal and thermoelectric materials are introduced, respectively. After that, the classification of different application areas of materials coupling photothermal effect with thermoelectric effect, such as sensors, thermoelectric batteries, wearable devices, and multi-effect devices, is reviewed. Meanwhile, the potential applications and challenges to be overcome for future development are presented, which are of great reference value in waste heat recovery as well as solar energy resource utilization and are of great significance for the sustainable development of society. Finally, the challenges of photothermoelectric materials as well as their future development are summarized.

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.