Supraja Potu

Conductive hydrogels, owing to their excellent stretchability, flexibility, and electrical conductivity, have emerged as promising materials for next-generation flexible electronics, wearable sensors, and energy harvesting devices. Herein, we report an ultrastretchable conductive hydrogel based on a polyacrylamide/sodium alginate (PAM/SA) dual-network matrix integrated with a synergistic hybrid conductive framework composed of Ti3C2Tx MXene and reduced graphene oxide (rGO) nanosheets. Benefiting from the complementary interfacial interactions and structural characteristics of the two-dimensional (2D) nanofillers, the resulting MXene/rGO hydrogel exhibits significantly enhanced stretchability and electrical conductivity compared to pristine and single-filler systems. The M15R5 hydrogel-based strain sensor offers a high fracture elongation of 1765%, excellent structural strength of 0.35 MPa, toughness of 3.0 MJ/m3, a high gauge factor (GF = 2.26) over an extensive strain range of 100–700%, a rapid response of approximately 290 ms, and retains excellent durability for beyond 1000 stretch–release cycles. The intrinsic interlayer slip characteristics and high aspect ratios of MXene and rGO, together with their surface-abundant hydrophilic functional groups, create a synergistic, interconnected conductive network that efficiently couples ionic and electronic transport under deformation. Furthermore, the developed hydrogel film was employed as a soft electrode material for triboelectric nanogenerator (TENG) applications in mechanical energy harvesting. The synergistic interaction between ion migration and electron transport significantly enhanced the triboelectric energy conversion performance, delivering a high output voltage of 180 V and a power density of 3.21 W/m2. These results demonstrate the strong potential of the developed hydrogel as a high-performance sensing material and stretchable soft electrode for next-generation energy harvesting systems and flexible electronic devices.

Conductive hydrogels are emerging as key materials for next‐generation wearable and self‐powered sensing systems due to their intrinsic softness, high stretchability, and skin‐like mechanical compliance. However, achieving long‐term mechanical durability and stable electrical performance requires a balance between softness and tensile strength. Herein, we report a double‐crosslinked conductive hydrogel based on hydrophilic polymers, polyacrylamide, and sodium alginate (PAM/SA), integrated with zeolitic imidazolate framework‐8 (ZIF‐8) nanoparticles. For the first time, the multifunctional electromechanical role of ZIF‐8 is exploited within a PAM/SA hydrogel matrix, where hydrogen‐bonding interactions act as reversible physical crosslinks, enhancing conductivity, tensile strength, stretchability, and durability. The optimized 1 wt.% ZIF‐8@PAM/SA hydrogel exhibits an ultrahigh stretchability of 1864%, a toughness of 2940 kJ m ^{− 3} , and strain‐sensing performance with a gauge factor of 0.48. The hydrogel further functions as a soft electrode for triboelectric nanogenerators (TENGs), delivering a power density of 1.16 W m ^{− 2} , sufficient to power approximately 60 light‐emitting diodes. In addition, the multifunctional hydrogel demonstrates excellent performance in tactile sensing, human motion monitoring, physiological signal detection, and handwriting recognition. Therefore, this work highlights the potential of the developed hydrogel for applications in wearable and self‐powered electronic systems.

Triboelectric nanogenerators (TENGs) have emerged as a promising alternative technology for sustainable energy harvesting, which is aligning with Sustainable Development Goal 7 (SDG 7). Strategies such as optimizing material selection, modifying surface morphology, and engineering interfacial structures have been explored to enhance TENG performance. However, the role of semiconductor metal oxides in TENG applications remains relatively underexplored. In this manuscript, the role of titanium dioxide (TiO₂), particularly its rutile and anatase phases, in improving the output performance of TENGs is investigated. The fabricated TiO₂‐based TENGs are systematically analyzed, revealing that rutile‐phase TiO₂ demonstrated superior performance compared to anatase, with a 1.25‐fold increase in voltage and a 1.16‐fold increase in current. This enhancement is attributed to rutile's higher dielectric constant, improved charge mobility, and optimized surface morphology. The optimized TiO₂‐based TENG achieved impressive performance metrics, including a voltage output of 500 V, a current output of 140 µA, and a power density of 8.16 W m ^{− 2} , making it highly suitable for self‐powered applications. The present findings underscore the viability of TiO₂‐based TENGs as a scalable and efficient energy solution, paving the way for sustainable and self‐powered applications.

Nowadays, the liquid-solid triboelectric nanogenerator (L-S TENG) has gained much attention among researchers because of its ability to be a part of self-powering technology by harvesting ultra-low-frequency vibration in the environment. The L-S TENG works with the principle of contact electrification (CE) and electrostatic induction, in which CE takes place between the solid and liquid. The exact mechanism behind the CE at the L-S interface is still a debatable topic because many physical parameters of both solid and liquid triboelectric layers contribute to this process. In the L-S TENG device, water or solvents are commonly used as liquid triboelectric layers, for which their wettability over the solid triboelectric layer plays a significant role. Hence, this review is extensively focused on the influence of the wettability of solid surfaces on the CE and the corresponding impact on the output performance of L-S TENGs. The present review starts with introducing the L-S TENG, a mechanism that contributes to CE at the L-S interface, the significance of hydrophobic materials/surfaces in TENG devices, and their fabrication methods. Further, the impact of the contact angle over the electron/ion transfer over various surfaces has been extensively analyzed. Finally, the challenges and future prospects of the fabrication and utilization of superhydrophobic surfaces in the context of L-S TENGs have been included. This review serves as a foundation for future research aimed at optimizing the L-S TENG performance and inspiring new approaches in material design and multifunctional energy-harvesting systems.

In this manuscript, we present a novel approach for integrating Triboelectric Nanogenerators (TENGs) into signature stamps, termed Stamp TENG (S-TENG). We have modified a commercially available stamp holder to integrate triboelectric layers for multiple applications like effective energy harvesting, sensing, and embedded electronics for data prediction. S-TENG has been further explored in remote monitoring systems for elderly individuals and for gathering real-time statistics regarding persons or events at specific locations. The S-TENG is fabricated using FEP and Al as functional layers. It demonstrates an output voltage of 310 V, a current of 165 μA, and a power density of 14.8 W/m². The simplicity of the S-TENG’s design is noteworthy. Its ability to generate energy through simple, repetitive stamping actions, which anyone can perform without specialized training, stands out as a key feature. The device is also designed for ease of use, being handheld and user-friendly. Its flexible and adaptable structure ensures that individuals with varying physical capabilities can comfortably operate it. An impressive capability of the TENG is its ability to illuminate 320 LEDs with each stamp press momentarily. Furthermore, using energy management circuits, the S-TENG can power small electronic gadgets such as digital watches and thermometers for a few seconds. In addition, when integrated with electronics, the S-TENG shows great potential in data prediction for various practical applications.

In recent years, multifunctional applications of the same material have gained wide recognition in various fields. The present study reports the synthesis, characterization, and multifunctional applications of europium (Eu)‐doped yttrium oxide (Y₂O₃) nanophosphor. Synergistic optimization of Eu‐doped Y₂O₃ results in enhanced photoluminescence (PL) and triboelectric nanogenerator (TENG) performance. Eu‐doped Y₂O₃ nanophosphors are synthesized using an autocombustion method, and comprehensive characterizations are conducted. The investigations indicate that the Eu doping significantly influences the PL intensity, with the highest emission observed at 3 mol% for powders. The synthesized nanophosphors are blended with silicone to fabricate hybrid films, which are utilized for energy harvesting applications using TENG technology. The TENG devices fabricated with these hybrid films demonstrate a notable relationship between the Eu concentration and the electrical output, achieving peak performance at 1 mol% Eu doping. The maximum output voltage of ≈535 V, short‐circuit current of ≈38 μA, and power density of 800 mW m⁻² are observed. Further, TENG is demonstrated in a self‐powered UV photodetector application. The present results contribute to the improvement of sustainable energy technologies and open up a new window for multifunctional materials.