Nanorods Research Articles

Low-Intensity Light Detection with a High Detectivity Using 2D-Sb2Se3 Nanoflakes on 1D-ZnO Nanorods as Heterojunction Photodetectors.

Multifunctional photodetectors (PDs) with broadband responsivity (R) and specific detectivity (D*) at low light intensities are gaining significant attention. Thus, we report a bilayer PD creatively fabricated by layering two-dimensional (2D) Sb2Se3 nanoflakes (NFs) on one-dimensional (1D) ZnO nanorods (NRs) using simple thermal transfer and hydrothermal processes. The unique coupling of these two layers of materials in a nanostructured form, such as 2D-Sb2Se3 NFs/1D-ZnO NRs, provides an effective large surface area, robust charge transport paths, and light-trapping effects that enhance light harvesting. Furthermore, the combination of both layers can effectively facilitate photoactivity owing to proper band alignment. The as-fabricated device demonstrated superior overall performance in terms of a suitable bandwidth, good R, and high D* under low-intensity light, unlike the single-layered 1D-ZnO NRs and 2D-Sb2Se3 NF structures alone, which had poor detectivity or response in the measured spectral range. The PD demonstrated a spectral photoresponse ranging from ultraviolet (UV) to visible (220-628 nm) light at intensities as low as 0.15 mW·cm-2. The PD yielded a D* value of 3.15 × 1013 Jones (220 nm), which reached up to 5.95 × 1013 Jones in the visible light region (628 nm) at a 3 V bias. This study demonstrated that the 2D-Sb2Se3 NFs/1D-ZnO NRs PD has excellent potential for low-intensity light detection with a broad bandwidth, which is useful for signal communications and optoelectronic systems.

Synthesis and Optical Properties of CdSeTe/CdZnS/ZnS Core/Shell Nanorods.

Semiconductor nanorods (NRs) have great potential in optoelectronic devices for their unique linearly polarized luminescence which can break the external quantum efficiency limit of light-emitting diodes (LEDs) based on spherical quantum dots. Significant progress has been made for developing red, green, and blue light-emitting NRs. However, the synthesis of NRs emitting in the deep red region, which can be used for accurate red LED displays and promoting plant growth, is currently less explored. Here, we report the synthesis of deep red CdSeTe/CdZnS/ZnS dot-in-rod core/shell NRs via a seeded growth method, where the doping of Te in the CdSe core can extend the NR emission to the deep red region. The rod-shaped CdZnS shell is grown over CdSeTe seeds. By growing a ZnS passivation shell, the CdSeTe/CdZnS/ZnS NRs exhibit a photoluminescence emission peak at 670 nm, a full width at a half maximum of 61 nm and a photoluminescence quantum yield of 45%. The development of deep red NRs can greatly extend the applications of anisotropic nanocrystals.

Microwave-assisted synthesis of Ni-doped europium hydroxide for photocatalytic degradation of 4-nitrophenol

Microwave-assisted synthesis method was used to prepare europium hydroxide (Eu(OH)3) and different percentages of 1, 5, and 10 % nickel-doped Eu(OH)3 (Ni–Eu(OH)3) nanorods (NRs). X-ray diffraction study showed a hexagonal phase with an average crystallite size in the range of 21 – 35 nm for Eu(OH)3 and Ni–Eu(OH)3 NRs. FT-IR and Raman studies also confirmed the synthesis of Eu(OH)3 and Ni–Eu(OH)3. The synthesized materials showed rod-like morphology with an average length and diameter between 27 – 50 nm and 8 – 13 nm, respectively. The band gap energies of Ni–Eu(OH)3 NRs were reduced (4.06 – 3.50 eV), which indicates that the doping of Ni2+ ions has influenced the band gap energy of Eu(OH)3. The PL study exhibited PL quenching with Ni doping. The photocatalytic degradation of 4-nitrophenol (4-NP) by the synthesized materials under UV light irradiation was investigated, in which 10 % Ni–Eu(OH)3 NRs showed the best response. A kinetic study was also conducted which shows pseudo-first-order kinetics. Based on this, Ni–Eu(OH)3 NRs have shown a potential to be a UV-light active material for photocatalysis.

Hydrothermal synthesis of high-performance cobalt phosphate nanorod architecture as bifunctional electrocatalysts for rechargeable Zn-air batteries and supercapatteries

Transition metal phosphate bifunctional electrocatalysts demonstrate superior oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and capacitive properties owing to their high electrocatalytic and conductive activities. In this report, cobalt phosphate (Co3P2O8) nanorod (NR) electrocatalytic materials were developed via a facile one-step hydrothermal synthesis, followed by an annealing process. The unique NR structures offer superior electrocatalytic activities, continuous and quick electron transport pathways, short ion diffusion lengths, and rich active sites toward rechargeable zinc-air batteries (ZABs) and supercapatteries (SCs). The self-assembled Co3P2O8 NR electrocatalyst revealed higher current density values during the OER and ORR measurements than the commercially available Pt/C and IrO2 materials. The Co3P2O8 NR electrocatalyst exhibited an excellent OER overpotential of 180 mV. The electocatalyst also showed superior onset and half-wave potentials of 0.92 V and 0.80 V, respectively. Moreover, the fabricated Co3P2O8 NRs-based ZAB exhibited better durability than the Pt/C-based ZAB. Significantly, the Co3P2O8 NR electrode demonstrated an excellent specific capacity of 373 mAh g−1 with outstanding cycling stability of 99% after 5000 cycles. Additionally, the fabricated Co3P2O8 NRs//activated carbon SC demonstrated high specific energy and power densities of 25.62 Wh kg−1 and 2953.12 W kg−1, respectively with remarkable cycling stability of 89% after 7000 cycles. Specifically, the practical applicability of the fabricated Co3P2O8 NRs-based ZAB and SC was tested using a blue light-emitting diode nameplate energized by two devices in series. Overall, the catalytic and energy-storage properties of the Co3P2O8 NR material can provide a new pathway for high-energy electrochemical applications.

High-Speed and High-Responsivity Blue Light Photodetector with an InGaN NR/PEDOT:PSS Heterojunction Decorated with Ag NWs.

InGaN nanorods possessing larger and wavelength selective absorption by regulating In component based visible light photodetectors (PDs) as one of the key components in the field of visible light communication have received widespread attention. Currently, the weak photoelectric conversion efficiency and slow photoresponse speed of InGaN nanorod (NR) based PDs due to high surface states of InGaN NRs impede the actualization of high-responsivity and high-speed blue light PDs. Here, we have demonstrated high-performance InGaN NR/PEDOT:PSS@Ag nanowire (NW) heterojunction blue light photodetectors utilizing surface passivation and a localized surface plasmon resonance effect. The dark current is significantly reduced by passivating the InGaN NR surface states using PEDOT:PSS. The photoelectric conversion efficiency is significantly increased by increasing light absorption due to the electromagnetic field oscillation of Ag NWs. The responsivity, external quantum efficiency, detectivity, and fall/off time of the InGaN NR/PEDOT:PSS@Ag NW PDs are up to 2.9 A/W, 856%, 6.64 × 1010 Jones, and 439/725 μs, respectively, under 1 V bias and 420 nm illumination. The proposed device design presents a novel approach toward the development of low-cost, high-responsivity, high-speed blue light photodetectors for applications involving visible light communication.

La implanted band engineering of ZnO nanorods for enhanced photoelectrochemical water splitting performance

In the quest to improve photoelectrochemical water-splitting performance, we have doped lanthanum (La) in highly crystalline zinc oxide (ZnO) nanorods (NRs) using a facile and low-temperature hydrothermal route and successful substitution of La3+ at the Zn2+ site is confirmed from structural and chemical analysis. The tapered NRs morphology gained after La doping resulted in lower optical bandgap of 3.17 eV, enhanced visible light trapping, and multiphoton absorption, which assist in achieving good PEC activity. The La doping also offered higher Urbach energy (EU), subsidizing the number of oxygen vacancies. The UPS spectra show that La doping reduces conduction band energy level and endorses smooth charge transportation. The La-doped ZnO exhibits two times enhancement in photocurrent (1.54 mA·cm−2) compared to pristine ZnO (0.81 mA·cm−2). The higher applied bias to the photon conversion efficiency of ∼1.14% for La-doped ZnO confirms the efficient utilization of solar energy. The EIS measurements demonstrated reduction in charge transfer resistance with La-doping. Mott-Schottky analysis shows that La doping lowers the flat-band potential and enhances charge transportation, making it a potential photoanode for PEC water-splitting applications.

Laser-Printed Photoanode: Femtosecond Laser-Induced Crystalline Phase Transformation of WO3 Nanorods for Space-Efficient and Flexible Thin-Film Solar Water-Splitting Cells.

Despite its potential for clean hydrogen harvesting, photoelectrochemical (PEC) water-splitting cells face challenges in commercialization, particularly related its harvesting performance and productivity at an industrial scale. Herein, a facile fabrication method of flexible thin-film photoanode for PEC water-splitting to overcome these limitations, based on laser processing technologies, is proposed. Laser-induced graphene, a carbon structure produced through direct laser writing carbonization (DLWC), plays a dual role: a flexible and stable current collector and a substrate for the hydrothermal synthesis of tungsten trioxide (WO3) nanorods (NRs). To facilitate water-splitting, a femtosecond-pulsed laser (fs laser) is focused on the WO3 NRs, converting their crystalline phase from pristine orthorhombic to monoclinic structure without thermal damage. With NiFe layered double hydroxide (LDH) catalyst, the flexible thin-film photoanode exhibits good PEC performance (1.46mAcm-2 at 1.23 VRHE) and retains ≈90% of its performance after 3000 bending cycles. With its excellent mechanical properties, the flexible photoanode can be operated in various shapes with different curvatures, enabling space-efficient PEC water-splitting by loading larger photoanode within a given space. This study is expected to contribute to the advancement of large-scale solar water-splitting cells, introducing a new approach to enhance H2/O2 production and expand its application range.

Hysteresis loops on voltage-current characteristics and optical responses of PEDOT:PSS/ZnO nanorods/ZnO:Ga heterostructure

Volage (V)-current (I) curves of the poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/ZnO nanorods (NRs)/ZnO:Ga (GZO) heterostructure exhibited a rectification behavior with hysteresis loops both in forward voltage (VF) and reverse voltage (VR) regions. The ultraviolet (UV) light irradiation of 360 nm led to the increase in the reverse current (IR), i.e. generation of photocurrent (PC), and the decrease in the hysteresis loop area in the VF region. In dark, the 1/V vs. ln (I/V2) plot revealed that the dominant carrier transport mechanisms in the low- and the high-VF regions are the direct tunneling and the Fowler-Nordheim (F-N) tunneling through the dipole layer formed at the interface between the PEDOT:PSS and ZnO NRs layers, respectively. On the contrary, the carrier transport in the middle-VF region in dark was dominated by the bulk-limited mechanisms, such as the space-charge-limited (SCL) conduction controlled by the single shallow traps, the trap-free SCL conduction, and the trap-filled-limit conduction controlled by the traps with Gaussian distribution. The UV light irradiation changed the carrier transport mechanism in the middle-VF region to the trap-free SCL conduction. The resistive switching related to the hysteresis loop was found to be caused by the trapping and detrapping of the injected carriers at the traps. In dark, the maximum forward current was increased by the repetition of the VF sweep of 0 V → 5 V → 0 V, but decreased by the repetition of the VR sweep of 0 V → -5V → 0 V, indicating the possibility of the resistive memory. At the low VRs, PC spectra showed a main peak at 350 nm, which is corresponding to slightly higher photon energy than the bandgap energy of ZnO. Moreover, the existence of the tail extending into the bandgap was also observed on the PC spectra. From the time response of PC, the depth of the trap state was estimated to be 0.64–0.77 eV.

Para-Nitrophenol detection by an electrochemical approach based on two-dimensional binary metal oxides ZrO2-Nd2O3 nanorod fabricated with PEDOT:PSS onto glassy carbon electrode

In this approach, a wet chemical method was employed to synthesize the nanorods (NRs) of Zirconium oxide − Neodymium Oxide (ZrO2-Nd2O3) in an aqueous solution. Comprehensive characterizations encompassing ultraviolet/visible diffuse reflectance spectroscopy (UV/vis DRS), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), alongside field emission scanning electron microscopy (FESEM) equipped with X-ray energy-dispersive spectroscopy (EDS), were applied for optical, elemental, morphological, and structural analyses of resultant material. To fabricate a highly selective and ultra-sensitive electrochemical sensor for para-Nitrophenol (para-NP) in the presence of other interfering toxic chemicals, a glassy carbon electrode (GCE) was modified with a thin layer of ZrO2-Nd2O3NRs. Poly 3,4-ethylenedioxythiophene polystyrene sulfonate (PEDOT:PSS) served as an adhesive conducting binder in this modification process. Subsequently, we introduced a novel electrochemical approach for the first time for the detection of para-NP by making use of newly developed ZrO2-Nd2O3-NRs/PEDOT:PSS/GCE as selective para-NP electrochemical sensor in an aqueous medium. This innovative electrochemical approach exhibited remarkable electrochemical responses, featuring high sensitivity and long-term stability when applied to para-NP detection. The calibration curve demonstrated linearity across broad linear dynamic range (LDR) spanning para-NP concentrations from 0.1 pM to 0.1 mM. Key analytical parameters, including limit of detection (LOD) at signal-to-noise ratio (SNR) of 3, limit of quantification (LOQ), and sensitivity, were determined to be 0.0141 pM, 0.047 pM, and 0.67 μAμM-1cm−2, respectively, based also on the gradient of calibration plot. This sensor holds significant promise for real sample analysis aimed at preserving the natural environment. So, this study introduces a novel and well-structured approach to the development of a highly sensitive para-NP sensor utilizing ZrO2-Nd2O3-NRs/PEDOT:PSS/GCE, employing a reliable electrochemical approach.

Raman spectroscopy of thermo- and laser-induced transformations of gouache paint layer of copper phthalocyanine blue

Methods to control polymorphic modifications of phthalocyanines using optical (laser) radiation and possible photoinduced transformations of polymorphs are of practical interest in problems of identification and attribution of paintings, laser (micro)sampling, and the development of phthalocyanine structures for technical applications in optics, optoelectronics, and medicine. In this work, we compare the thermal and laser-induced changes of a gouache paint layer based on copper phthalocyanine (CuPc) PB15. The thermally induced color changes of the paint layer are quantified using the CIE Lab D65/10 color space. (Nano)rods formed in the paint layer when the sample is heated to 450°C at normal pressure without humidity control are studied using absorption spectroscopy, Raman microspectroscopy, and scanning electron microscopy. It is shown that the formation of (nano)rods is related to the α→β polymorph transition of CuPc. Low-frequency markers of the CuPc β-polymorph are revealed in the Raman spectra. For the sample containing (nano)rods, the a* color coordinate substantially increases (by about 30 units), whereas the L* and b* coordinates remain almost unchanged. Irradiation with a single nanosecond laser pulse at a wavelength of 532 nm leads to the laser ablation of the paint layer at fluences exceeding a threshold level of about 3 J/cm2. Irradiation at fluences of greater than 0.5 J/cm2, but lower than the ablation threshold leads to color change of the paint layer due to the α→ε transition of CuPc. Similar transformations are observed at the periphery of and inside ablation crater.

Programmable Colloids with Analogous Hypercoordination Complex Architectures.

Colloidal molecule clusters (CMCs) are promising building blocks with molecule-like symmetry, offering exceptional synergistic properties for applications in plasmonics and catalysis. Traditional CMC fabrication has been limited to simple molecule-like structures utilizing isotropic particles. Here, we employ molecular dynamics simulation to investigate the co-assembly of anisotropic nanorods (NRs) and the stimulus-responsive polymer (SRP) via reversible adsorption. The results of the simulation show that it is possible to fabricate hypercoordination complex structures with high symmetry from the co-assembly of NRs and the SRP, even in analogy to the Th(BH4)4 structure. The coordination number of these CMCs can be precisely programmed by adjusting the shape and size of the ends of the NRs and the SRP cohesion energy. Furthermore, a finite-difference time-domain simulation indicates these hypercoordination structures exhibit significantly enhanced optical activity and plasmonic coupling effects. These findings introduce a new design approach for complex molecule-like structures utilizing anisotropic nanoparticles and may expand the applications of CMCs in photonics.

Transformative Dynamics: Self-Assembly of Iron Oxide Hydroxide Nanorods into Iron Oxide Microcubes for Enhanced Perfluoroalkyl Substance Remediation.

We report the controlled synthesis of iron oxide microcubes (IOMCs) through the self-assembly arrays of ferric oxide hydroxide nanorods (NRs). The formation of IOMCs involves a complex interplay of nucleation, self-assembly, and growth mechanisms influenced by time, thermal treatment, and surfactant dynamics. The self-assembly of vertically aligned NRs into IOMCs is controlled by dynamic magnetism properties and capping agents like cetyltrimethylammonium bromide (CTAB), whose concentration and temperature modulation dictate growth kinetics and structural uniformity. These controlled structural growths were obtained via a hydrothermal process at 120 °C at various intervals of 8, 16, 24, and 32 h in the presence of CTAB as the capping agent. In this hydrothermal method, the formation of vertically oriented NR arrays was observed without the presence of ligands, binders, harsh drying techniques, and solvent evaporation. The formation of the self-assembly of NRs to IOMCs is obtained with an increase in saturated magnetization to attain the most stable state. The synthesized IOMCs have a uniform size, quasi-shape, and excellent dispersion. Due to its excellent magnetic and catalytic properties, IOMCs were employed to remove the various emerging pollutants known as per- and polyfluorinated substances (PFAS). Various microscopic and spectroscopic techniques were employed for the characterization and interaction studies of IOMCs with various PFAS. The interaction between IOMCs and perfluoroalkyl substances (PFAS) was investigated, revealing strong adsorption tendencies facilitated by electrostatic interactions, as evidenced by UV-vis and FT-IR spectroscopic studies. Furthermore, the higher magnetic and positive surface charge of IOMCs is responsible for an effective remediation eliminating any secondary pollution with ease of recovery after the sorption interaction studies, thereby making it practically worthwhile.

Exploring highly electro-active zinc peroxide nanorod for selective detection of hydrazine

Hydrazine (N2H4), widely used as a raw material for producing synthetic catalysts, agricultural chemicals, and pharmaceutical products, has had an irreversible impact on air, water, and soil in the environment because of its high toxicity. To prevent making it lethal contamination should be monitored and detected. Here in this work, for the first time, Zinc peroxide (ZnO2) nanorods (NRs) were synthesized using a simple hydrothermal method to modify the gold electrode (AuE) for the fabrication of the ZnO2@AuE sensor. The fabricated sensor was successfully applied for the selective and efficient detection of hydrazine based on the chronoamperometry technique. According to theoretical calculations, the metal peroxide nanorods result in high oxygen vacancies, surface defects, and Zn ratios. This triggers substantial electron transfer, effectively enhancing the conductivity, electrocatalytic, and stability properties of the AuE with economic benefits. The effect of surface modification on the bare electrode was analyzed using the EIS technique. The ZnO2/Au electrode's electrochemical behavior towards hydrazine was studied using cyclic voltammetry (CV) at a scan rate of 70 mVs−1. Further, chronoamperometry was applied to investigate the effect of time, pH, nanorod concentration, and scan rate on the analytical performance parameters of the electrode ZnO2@AuE. The developed sensor (ZnO2/AuE) demonstrated an excellent detection limit (LOD) of 4.09 nM and good sensitivity of 2.4 × 10−2 µAµM−1cm−2 towards the oxidation of hydrazine having a fast response time (within 5 s). The developed sensors promise reproducible results along with good stability, which makes them effective for the electrochemical sensing of hydrazine. Such outstanding sensing performance is attributed to the tailored direct electrochemical redox surface of ZnO2, which led to selective sensing of hydrazine in tap, distilled, and sewage water. Keeping these features into consideration, our developed sensor can be adopted for real applications, especially for environmental surveillance.

Non-enzymatic Glucose Detection by Fe2O3 Nanorods-reduced Graphene under Physiological pH

Background: Non-enzymatic detection has become a research hotspot because of its alternativity in solving problems compared to enzymatic biosensors, but most of those sensors require a strong basic pH environment (higher than 10) to active their surface, restricting their use in clinical detection because the pH of body fluid is around 7.4. Furthermore, metal oxide sensors with specific morphologies are reported to have a fast electrocatalytic response. Therefore, Fe2O3 nanocomposites with porous structure are selected for glucose detection research in a physiological pH environment. Objective: The study aimed to assess the potential use of porous reduced graphene oxide-Fe2O3 nanorods in glucose detection in a physiological pH environment. Method: Hydrothermal method was used to prepare porous Fe2O3-rGO NRs (Nanorods) and hollow Fe2O3/C nanoparticles. Cyclic voltammetry and electrochemical impedance spectroscopy were used to evaluate the performance of our materials. Results: Porous-reduced graphene oxide-Fe2O3 nanorods have exhibited better performance than hollow carbon-Fe2O3 core-shell nanoparticles for glucose detection in a physiological pH environment. Conclusion: Non-enzymatic glucose sensing based upon cavity Fe2O3-rGO NRs under a physiological pH environment has been successfully realized, attributing to their high electron mobility and large specific surface area. Furthermore, the results of this work indicate that the glucose sensor prepared here has shown good repeatability and stability, which suggests its potential use in clinical detection.

Pd(II), Pt(II), Zn(II), Cd(II) and Hg(II) complexes of the newly prepared 1,2-benzo- isothiazol-3(2H)-dithiocarbamate (BIT-DTC) ligand

In the current work, we report the synthesis and characterization of new dithiocarbamate complexes derived from 1,2-benzoisothiazol-3(2H)-one (BitH). The ligand was synthesized by treating the BitH with carbon disulfide in a basic solution. The NMR technique confirmed the preparation of the ligand. The treatment of the Bit-dtcNa with the metal salt’s solution afforded the complexes of the type [M(Bit-dtc)2]; M = Zn, Cd, Hg, Pd, and Pt. The complexes were characterized via FT-IR and 1H-NMR techniques. The Zn, Pd, and Pt complexes were investigated theoretically, and some of their quantum properties were determined. These parameters include HOMO-LUMO energies, electron affinity, ionization potential, chemical hardness, dipole moment and the total energies of the optimized structures. Moreover, the surface structure of Zn and Hg complexes were investigated by SEM and XRD techniques. The SEM pattern showed a cubic structures for the Zn complex while the Hg complex appeared as a nano rods structure. The calculated average particle sizes for Zn and Hg complexes were 23 and 26 nm, respectively. KEY WORDS: Dithiocarbamate, 1,2-Benzoisothiazol-3(2H)-one, DFT, SEM, XRD Bull. Chem. Soc. Ethiop. 2024, 38(3), 889-899. DOI: https://dx.doi.org/10.4314/bcse.v38i4.6

High Color Conversion Efficiency Realized in Graphene‐Connected Nanorod Micro‐LEDs Using Hybrid Ag Nanoparticles and Quantum Dots

AbstractIn this paper, a uniform nanorod (NR) array is etched onto the surface of Micro‐Light‐Emitting‐Diodes (µLEDs) and mix Ag nanoparticles (NPs) with QDs to fill the gaps between the nanorods. Simultaneously, the study utilizes graphene to connect individual nanorods and enhance current spreading. The nanorod array's structure significantly reduces the distance between the QDs and the quantum well (QW), reducing energy loss from the excitation light source through a non‐radiative energy transfer (NRET) mechanism. Additionally, the Ag NPs function as localized surface plasmons (LSPs), further enhancing the CCE of QDs via the absorption resonance. In this study, the effects of two types of Ag NPs are compared with different absorption resonance peaks on device performance. The results demonstrate that Ag NPs with absorption resonance peaks matching the emission wavelength of QDs play a more crucial role in the system. This configuration achieves a CCE of 77.78% for µLEDs with nanorod arrays, operating at a current of 10 mA. Compared to the conventional µLED structure with QDs only on the surface, the proposed method improves the CCE of µLEDs by an impressive 86.5%. This outcome underscores the significant contribution of the NR structure and LSPs in enhancing the CCE of QD‐µLEDs.

Enhanced thermal conductivity in vertically grown ZnO Nanorods/ Poly(3,4-ethylenedioxithiophene): Poly(4-styrenesulfonate) composite thin films

Herein, we have investigated the thermal properties of compact and vertically grown ZnO nanorods (NRs)/poly(3,4-ethylenedioxithiophene):poly(4-styrenesulfonate) (PEDOT:PSS) composite film. The ZnO NR arrays with length 885 ± 5 nm have been grown using the sol–gel method. Furthermore, composite films of compact-ZnO and ZnO NR with PEDOT:PSS have also been grown. The temperature-dependent thermal conductivity for both the composite films has been investigated in the temperature range of 273–353 K. The thermal conductivity of compact-ZnO/PEDOT:PSS is found to be in between 1.43–1.49 W/mK. The thermal conductivity is found to be enhanced significantly in the case of ZnO NR/PEDOT:PSS composite film.

Textured CsPbI3 nanorods composite fibers for stable high output piezoelectric energy harvester

The utilization of piezoelectric nanogenerator (PENG) based on halide perovskite materials has demonstrated significant promise for energy harvesting applications. However, the challenge of synthesizing halide perovskite materials with both high output performance and stability using a straightforward process persists as a substantial obstacle. Herein, we present the fabrication of CsPbI3 nanorods (NRs) exhibiting highly uniform orientation within polyvinylidene fluoride (PVDF) fibers through a simple texture engineering approach, marking the instance of enhancing PENG performance in this manner. The resultant composite fibers showcase a short-circuit current density (Isc) of 0.78 ​μA ​cm−2 and an open-circuit voltage (Voc) of 81 ​V, representing a 2.5 fold increase compared to the previously reported highest value achieved without the electric poling process. This outstanding output performance is ascribed to the orientation of CsPbI3 NRs facilitated by texture engineering and dipole poling via the self-polarization effect. Additionally, the PENG exhibits exceptional thermal and water stability, rendering it suitable for deployment in diverse and challenging environmental conditions. Our findings underscore the significant potential of textured CsPbI3 NRs composite fibers for powering low-power consumer electronics, including commercial LEDs and electronic watches.

Highly Semiconducting One-Dimensional Porous ZnO Nanorod Array Nanogenerators for Mechanical Energy Harvesting Functions

The development of energy harvesters based on inexpensive inorganic materials has attracted considerable attention to envisage next-generation self-powered electronic devices. In this work, we presented surface modification of ZnO nanorods (NRs) by thermochemical reaction using photoresist (PR) as an etching source. The morphological and microstructural properties of surface-etched ZnO NRs (M: ZnO) were systematically studied in detail through SEM and HRTEM. The morphological results show that the surface-etched NRs possess nanofiber-like porous structures and are penetrated throughout the NRs with high surface area. We fabricated triboelectric nanogenerators (TENG) using M: ZnO NRs with poly (dimethylsiloxane) (PDMS) as negative triboelectric material and mica as positive triboelectric material. The prepared M: ZnO NR TENG successfully delivered an output voltage of up to 20 V and a current density of 3.2 μA cm−2, which is ∼1.5 times higher than those observed for smooth ZnO NRs, respectively. The prepared M: ZnO NR TENG device can be able to lit 24 red light-emitting diodes (LEDs) as the power source. Finally, to demonstrate the practical applications of M: ZnO NR TENG, it was attached to the human body (elbow, knee, wrist, and heel) and efficiently harvested the energy from daily human activities.

Sonication supported green modulation of Fe:MoO3/g-C3N4 heterojunction as solar light sensitive photocatalyst for dye degradation and photoelectrochemical water splitting

The concerns of dye in an aquatic system associated with acute toxicity and carcinogenicity, and the increase in demand for hydrogen production has led to a keen interest in advancing solar driven methodologies utilizing potent photocatalysts to address environmental concerns through sustainable remediation practices. In this pursuit, we synthesized a heterostructure comprised of Fe doped MoO3 (Fe:MoO3), anchored on g-C3N4 sheet as a photocatalyst denoted as Fe:MoO3/g-C3N4, employing a sonication supported green synthesis method with the aid of Murraya paniculata leaf extract. We explored structural, morphological, and surface characteristics using various analytical techniques, including X-Ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, Field emission scanning electron microscopy (FE-SEM) and High-resolution transmission electron microscopy (HR-TEM), X-Ray photoelectron spectroscopy, and BET for a comprehensive surface analysis. The outcomes highlighted the exquisitely oriented and interconnected arrangement of MoO3 nano rods ensconced within a piled layer of g-C3N4. The XRD patterns unveiled the coexistence of g-C3N4 and Fe:MoO3 within the heterojunction structure. FESEM and HRTEM image analysis of Fe:MoO3/g-C3N4 heterojunction reveals a g-C3N4 nanosheet wrapping the Fe:MoO3 nanoparticles with the formation of nanorods of MoO3 with an average thickness of 9.46 nm containing circular Fe nanoparticles with a mean diameter of 8.97 nm. This intricate configuration resulting in a decrease of the size of the nanoparticle caused by effective sonication-supported green modulation configuration facilitated an optimized charge flow, contributing to the elevated photo assisted catalytic performance of the heterojunction. The Fe:MoO3/g-C3N4 semiconductor heterojunction exhibited a considerable surface area and pore volume, inherently amplifying the sites of the activity on the surface and thereby enhancing photoactivity. As opposed to both g-C3N4 and the Fe:MoO3 nanoparticles, the Fe:MoO3/g-C3N4 semiconductor heterojunction showcased enhanced photocatalytic effectiveness in the degradation of dye Crystal violet (CV). Under optimized circumstances, the photo assisted degradation of dye CV by the semiconductor heterojunction adhered to pseudo-first-order kinetics. The active species responsible for the photo assisted degradation process is identified as •O2−. These findings not only emphasize the enhanced efficacy of the developed semiconductor heterojunction but also reveal its potential for addressing the environmental challenges posed by dye CV contamination through prolonged and efficient photocatalytic remediation practices. A marked improvement in both photo assisted catalytic and photoelectrochemical (PEC) water splitting activities under visible light exposure was showcased. The augmented performance of the Fe:MoO3/g-C3N4 semiconductor heterojunction in photodegradation and PEC water splitting activities can be attributed to the extended absorption of visible light. Additionally, the synergistic influence of g-C3N4, contributes positively to the separation of charges and expedites the transfer efficiency of photogenerated charge carriers. This synergy enhances the overall effectiveness of the nanoparticles in harnessing visible light for efficient water-related processes.