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The emergence of tribovoltaic nanogenerators (TVNGs) paves the way for developing a new kind of semiconductor‐based energy harvester that overcomes the restriction of low output current in a conventional approach. The traditional TVNG generally depends on the frictional pair between two rigid semiconductors (or metal‐semiconductor), limiting the practicability of flexible and portable electronics. Recent developments require the fundamental understanding of charge generation in diverse operating modes and structures. Here, a flexible TVNG based on the p‐Cu2O/n‐g‐C3N4 interface is presented. Operating in a freestanding mode, the proposed TVNG can generate a stable signal in any optical conditions including UV illumination, dark, and ambient. Under UV illumination, the electrical outputs of the TVNG reach 0.43 V and 2.1 µA cm−2, which are significantly larger than those obtained from dark and ambient conditions. The results demonstrate the coupling effect of three phenomena: tribovoltaic, photovoltaic, and triboelectric effects, and the unique mechanism to the observed signal is proposed. Additionally, the TVNG shows the practical feasibility of energy harvesting with capacitor charging and charge‐boosting circuits. This study showcases the unique concept with potential for developing a novel flexible nanogenerator in many aspects, including material, structure, and fundamental mechanism. [ABSTRACT FROM AUTHOR]

Transparent, flexible, and high-performance triboelectric nanogenerator (TENG) from nature-derived materials are required for sustainable society development. However, low triboelectricity from natural material is generally observed. Tunable electronic band diagram (EBD) through facile manipulation is one of the efficient methods to promote the TENG output, requiring fundamental, in depth understanding. Herein, we employed the high quality, single crystal-like Ti2NbO7 nanosheets (NSs) with dual dielectric and semiconducting properties as filler for bacterial cellulose (BC)-based TENG. Several techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), ultraviolet—visible (UV—vis) absorption, energy dispersive X-ray spectroscopy (EDS), and synchrotron radiation X-ray tomographic microscopy (SRXTM) were applied to characterize the long-range structure, microstructure, optical properties, elemental composition, and three-dimensional (3D) distribution of components in the composites. The semi-transparent and flexible 5 vol.% Ti2NbO7 NSs/BC preserved the integrity of cellulose, contained well-dispersed nanosheets, reduced optical band gap (4.20 vs. 5.75 eV for BC), and increased surface roughness. The dielectric permittivity and conductivity increased with nanosheets content. Adding negatively-charged Ti2NbO7 NSs could regulate the charge affinity of BC composite via shifting of Fermi energy over that of Al. It is found that adding 5 vol.% NSs into the BC film improved electrical outputs (~ 36 V and ~ 8.8 µA), which are 2–4 times higher than that of pure BC, even when paired with Al which lies adjacent in triboelectric series. Our work demonstrated the method to enhance BC-based TENG performance through EBD regulation using multifunctional Ti2NbO7 NSs. [ABSTRACT FROM AUTHOR]

There is a need to develop inexpensive, lightweight, and flexible high‐performance triboelectric nanogenerators (TENGs) from renewable resources. Here, a multifunctional cellulose filter paper (CFP)‐based TENG consisting of dielectric Ti0.8O2 nanosheets (Ti0.8O2 NSs) and conducting Ag nanoparticles (Ag NPs) is prepared by a simple dip coating method. The incorporation of dielectric Ti0.8O2 NSs onto the CFP significantly improves charge generation, while the inclusion of Ag NPs provides an electrically conductive path for charge transportation. The presence of these fillers can be deduced from XRD, SEM, EDS, X‐ray photoelectron spectroscopy, and Raman spectroscopy. Their distribution is visualized in 3D by synchrotron radiation X‐ray tomography. The present CFP‐based TENG provides an output voltage and current density of ≈42 V and ≈1 µA cm−2, respectively with the power density of ≈25 µW cm−2. It is capable of lighting up 40 light‐emitting diode bulbs and charging a 0.22 µF capacitor to 8 V in only 5 s. The developed TENG is also capable of detecting simple human motions, i.e., finger tapping, finger rubbing, and foot trampling. This work offers a facile design of low cost yet efficient paper‐based TENG by dual modification with multifunctional nanomaterials, and also demonstrates its use as a feasible power source that not only drives small electronics, but also scavenges energy from human actions. [ABSTRACT FROM AUTHOR]

• Enhancing the electrical output performance of a composite piezoelectric nanogenerator based on BCZT/MCNTs/PDMS through triboelectric hybridization. • The piezo-triboelectric nanogenerator, based on the BCZT/MCNTs/PDMS composite, demonstrated optimal electrical output performance at a 50 wt%-BCZT ratio (V OC ∼ 39.7 V, I SC ∼ 1.9 µA, peak-to-peak power of ∼ 157.7 µW, and power density of ∼ 9.85 µW/cm2) under a compressive load force of 500 N and a frequency of 1 Hz. • The piezo-triboelectric nanogenerator device exhibits promising potential for energy harvesting under high compressive loading at low frequencies. This work has developed a novel piezo-tribo-electric nanogenerator (P-TENG) that is capable of converting mechanical energy into electrical energy when operating in compressive mode. An arch-shaped P-TENG device was formed using an optimal piezoelectric polymer composite, which was fabricated using a polydimethylsiloxane (PDMS) matrix that was modified with piezoelectric (Ba 0.85 Ca 0.15) (Ti 0.90 Zr 0.10)O 3 (BCZT) ceramic particles and electrically conductive multi-walled carbon nanotubes (MCNTs). A high filler loading of BCZT (40, 50, 60 wt%) and 3 wt% of MCNTs was formed into a 0–3 connectivity composite. The P-TENG device containing 50 wt% BCZT exhibited the highest electrical output (V OC ∼ 39.7 V, I SC ∼ 1.9 µA, and maximum power ∼ 157.7 µW), compared to the other composites, when subjected to an alternating compressive load of 500 N at a 1 Hz frequency. This research provides new composite formulations for elastomeric-based energy generators that are responsive to low frequency mechanical oscillations. [Display omitted] [ABSTRACT FROM AUTHOR]

Recent advances in achieving flexible triboelectric nanogenerators (TENGs) focus widely on utilizing and modifying abundant natural biopolymer. Boosting power generation and conversion efficiency continue to prevail. In this work, three main strategies were proposed to enhance the output performance of chitosan-based TENGs; 1) hybridization with lead-free piezoelectric nanorod, 2) introduction of a soft electrode using bacterial cellulose/carbon nanotube composite to enhance contact efficiency, and 3) enhancement of charge density of the triboelectric friction layer using a self-charge pumping (SCP) module. Under the same testing conditions of 48 ± 5% relative humidity, ~ 0.55 Hz of frequency, ~ 250 N of compressive force at 25.0 ± 0.5 °C, and the combination of 7 wt% lead-free piezoelectric BaTiO 3 nanorods (BT-NRs) in the chitosan matrix, the highest open-circuit voltage (V oc) of ~111.4 V, short circuit (I sc) of ~21.6 μA/cm2, and also output power density of 756 μW/cm2 was achieved. By using an integrated SCP module, the TENGs can provide a V oc , I sc and peak power output of 247.2 V, 36.7 μA/cm2 and 1568 μW/cm2, respectively. This electrical power output rises to over 4-fold more power enhancement than that of pristine chitosan TENGs. The TENGs demonstrate remarkable mechanical stability and reliability upon cyclical contact for up to 3000 times. This work provides a promising strategy for achieving high-output, eco-friendly triboelectric nanogenerators. By boosting the output performance via continuous charge pumping, ultrahigh effective charge density was achieved successfully in flexible chitosan/BT-NR biocomposites that can push output performance towards real applications of TENGs. Image 1 [ABSTRACT FROM AUTHOR]