Flexible and sustainable supercapacitors (SCs) were fabricated with carbon nanotubes (CNTs) as the anode and recycled aluminium as the cathode (obtained from soda cans). Devices made with the configuration of CNT//Al had maximum energy-densities/capacitances of 97.8 Wh kg−1/313.5 F g−1. Later, MnCoGe (MCG) alloy powders doped with boron (MCG:B) or gallium (MCG:Ga) were incorporated into the SC electrodes and the energy-density/capacitance was enhanced up to 269.5 Wh kg−1/862.3 F g−1. This outstanding increment of the electrochemical performance was caused by the formation of multiple redox centers on the SC electrodes (oxygen vacancies, Mn3+/Mn4+, Co2+/Co3+, and Ge4+/Ge2+/Ge0) as confirmed by XPS and Raman spectroscopies. The SCs made with MCG alloys were immersed in acid (pH=3)/basic (pH=11) aqueous media and electrochemically tested. Surprisingly, the capacitance retention was reduced a maximum of 0.6%, demonstrating their capacity to operate underwater. The tests of bending and charging/discharging cycles demonstrated that the SCs made with the MCG:B powder were the most stable because their capacitance retention was above 95%. In contrast, SCs made with the MCG:Ga alloy had capacitance retentions below 93% after the same tests. Overall, we demonstrated that efficient/flexible/waterproof SCs can be made with low-cost aluminium, which of interest for wearable electronics.

This study explores the optimization of hole transport material (HTM)-free perovskite solar cells featuring laminated free-standing carbon film as a back electrode. Surface treatment of perovskite film using different types of solvent (chlorobenzene, toluene, and ethyl acetate) was carried out to improve the electrical contact at the carbon/methylammonium lead iodide interface. Overall, the surface treatment improved mechanical adhesion between the perovskite and carbon film. The conductivity of the free-standing carbon electrode was further improved by attaching the carbon film to various types of conductive support. Our results show that the selection of both solvents used during surface treatment and the type of conductive substrate has a considerable impact on the resulting performance, wherein all modifications gave rise to substantial improvement over the benchmark unmodified carbon electrode. A power conversion efficiency (PCE) of 7.74% was achieved by the perovskite solar cell with laminated carbon electrode on Al foil combined with the application of chlorobenzene as surface treatment, demonstrating a tremendous increase in performance compared to that of untreated free-standing carbon electrode that produced PCE less than 1%. The main contributor to the improved performance is presumably due to the low carrier recombination rate and improved charge carrier extraction as implied by the electro-impedance spectroscopy and photoluminescence analysis. This work demonstrates a facile approach for resolving the challenges in developing low-cost HTM-free perovskite solar cells with a free-standing carbon film electrode.

A dopant-free and low-cost hole transport material (HTM) with dibenzo[b,d]thiophene as the center unit, bis(4-methoxyphenyl)amine as the terminal unit, and fluorine substitution adjacent to the methoxyl (named DBT-4F-MOP) is designed and applied in inverted organic-inorganic hybrid perovskite solar cells (OIH-PSCs). The synthetic cost of DBT-4F-MOP in the lab is just as low as 115 CNY/g, which is much lower than the benchmark HTM poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA, 2500 CNY/g). Due to the introduction of the fluorine atoms, the annealing temperature of the HTM can be increased by over 150 ℃. The highest efficiency of the inverted device based on it can reach 16.8 %, with an open circuit voltage of 1.04 V, a short circuit current of 21.57 mA cm−2, and a fill factor of 74.69 %, while the reference device based on PTAA can reach a PCE of 17.54 %. This work provides an avenue for the design of low-cost, dopant-free, and high-annealing temperature HTMs for inverted OIH-PSCs.

Polyaniline (PANI) derivatives, such as poly(phenylenediamine) (para, ortho and meta derivatives) and their nanostructures are attracting immense interest in wide potential applications due to their unique multifunctionality. Here, we report synthesis of polymer nanotubes from poly (para-phenylenediamine) (PpPD) by a simple self-degrading template method using methyl orange (MO) as the structure-directing template and potassium persulfate (KPS) as the oxidant. Two experiment schemes with reversed additions of monomer and oxidant are tested and they demonstrate influence on morphology of the as-produced materials. Electron microscopy and diffraction studies show that the nanotubes with 80 −100 nm outer diameter and more than 1 μm in length, exhibit rectangular cross-section and partial crystallinity. The chemical structures of the material are characterized by EDX, FTIR and UV-Visible spectroscopy. Results show that PpPD nanotubes could be successfully prepared by the facile solution route and demonstrate that the MO template is versatile for preparing nanotubes for not only of conducting polymer but also for its derivative.

Electrochromic polymers have gained significant attention in electrochromism due to their distinctive features including facile preparation and enhanced processability, high optical contrast, fast response time, and low cost. Nevertheless, the synthesis of ECPs through coupling polymerization methods like Stille, Suzuki, Kumada, and Negishi are hindered by intricate synthetic steps and substantial production of toxic metal byproducts, which restricts their application. Compared with conventional polymerization methods, direct (hetero) arylation polymerization (DHAP) simplifies the polymer purification process, reduces the generation of toxic metal byproducts, and reduces the overall cost. Since 2006, DHAP polymerization has undergone rapid development in electrochromism. This review elucidates the basic parameters of electrochromism, analyzed the synthetic methodology of DHAP-prepared electrochromic conjugated polymers, and reviews recent advances of DHAP-prepared polymers in electrochromism including materials, devices, processing technologies and applications. Finally, we put forward our perspective on the future development of this field.

The relative humidity sensing response of the Polyaniline/ reduced Graphene Oxide (PRGO) composites has been explored in this present research work. For these observations, polyaniline (PANI), synthesised by the chemical oxidative polymerisation process, was physically blended using the different mass ratios of reduced graphene oxide (rGO). By the improved hummers method, graphene oxide (GO) is prepared, adding the minimal quantity of selenium power, and the GO was effectively and facilely reduced to rGO. By adding different weight per cent (wt%) of Graphene oxide (rGO) to the polymer matrix, PRGO composites were prepared. Structural and morphological properties of rGO were confirmed by XRD, RAMAN, FTIR, SEM, EDX, and HR-TEM (elementary mapping) characterisations. XRD, FTIR SEM and EDX proficiencies were employed to characterise the PRGO composites. For the humidity sensing determination, the sensing film of the PANI, rGO, and PRGO composites is groomed by loading the sample on an IDT substrate through a drop casting technique. The PRGO-3 composite has shown an epitome response and recovery of 3 and 4s, respectively. The PRGO-3 composite has the most minored and less real sensitivity with a lower limit of detection (LOD). Also, the prepared PRGO composites have recorded less hysteresis and good linearity and depicted exact stability over PANI and other PRGO composites. The physical parameters for PRGO composites were also calculated to determine the potentiality of a perfect sensor. The sensing mechanism also hashed out based on establishing chemisorption and physisorption layers.

The photocatalytic degradation of environmentally harmful chemicals has been extensively explored using a variety of photocatalysts and approaches. However, achieving efficient decomposition and removal of persistent contaminants from the aquatic environment remains a challenging factor. In this study, we report stannous sulfide nanoparticles (SnS2 NPs) prepared by a simple hydrothermal technique and characterized using various analytical methods. The prepared SnS2 NPs were used for the degradation of Methylene Blue (MB) dye under visible light irradiation, which resulted in outstanding degradation compared to other photocatalysts. According to our results, the SnS2 NPs can destroy 98.4% of MB dye (10 ppm) in 60minutes effectively, owing to a narrowed band energy gap and photo-induced carrier separation. Based on the results of free-radical scavenging experiment, we confirmed that hydroxyl radicals (•OH) are the key reactive species, and on this basis elucidated the possible degradation mechanism. Moreover, the SnS2 NPs photocatalyst exhibited good stability in degrading MB even after four recycles. Additionally, we analyzed the antibacterial activity of the prepared SnS2 NPs against pathogenic bacteria. As a result of this research, the proposed photocatalyst shows high potential for environmental remediation of harmful contaminants.