Transparent, Flexible Cellulose Nanofibril–Phosphorene Hybrid Paper as Triboelectric Nanogenerator

Abstract

transition metal dichalcogenides (TMD) materials have been well investigated and developed and applied in different fields such as transistors, [14] supercapacitors, [12,15] and photodetectors. [16] Que et al. reported using graphene oxide for acoustic energy harvester, [17] Tian et al. reported a graphene oxide based electrostatic nanogenerator, [18] and Wu et al. reported the piezoelectricity of single-layer MoS 2 . [19] Among all the 2D materials, phosphorene: a monolayer of black phosphorus is generating interest due to the high carrier mobility up to 286 cm 2 V −1 s −1 [20] and good semiconducting properties. [21,22] In comparison to other 2D materials, phosphorene exhibits in-plane anisotropic transport and a tunable band gap with different numbers of layers. [21] However, the stability of phosphorene is still dire for real applications. [23] While exposed in the ambient condition, the phosphorus atoms would be oxidized into oxidation state with three to five neighboring phosphorous, oxygen, or hydrogen atoms. [24] Although, researchers have developed encapsulation techniques to protect the phosphorene surface against oxidation, [23] this is not an ideal way due to disturbance to the intrinsic property and additional cost. Density functional theory was used to evaluate the electrical properties of molecular doping of phosphorene. An open-circuit voltage of ≈2.7 V was calculated by using the molecular doped phosphorene. [25] So far, there is no report on the realization of phosphorenebased TENG, mainly due to its instability in the ambient condition. Here, we design and fabricate a tempo-oxidized cellulose nanofibril (CNF)/phosphorene based TENG, in which CNF is introduced as a supporting matrix or host material that does not contribute substantially or interfere the TENG performance due to the small positive charge of CNF (quite close to zero in the triboelectric series table). More importantly, CNF serves as a protection for the phosphorene against oxygen to solve the environmental stability issue. CNF is composed of nanosized cellulose fibrils with high length-to-width ratio. [26] Normally, CNFs are isolated from natural resources containing cellulose such as wood fibers. Through a series of treatment including high-pressure, high-temperature, and high velocity homogenization, the diameter of CNFs in the range of 5-20 nm can be achieved. [26] Hydrophobic repellent cellulosic substrates have been attained by further treatment using wax [27] or silica nanoparticles. [28] CNF has been found to serve as a protection matrix when premixed with silver nanowires (AgNWs) in the fabrication of transparent conducting paper without disturbing Few-layered phosphorene is exfoliated through a liquid phase exfoliation in ethanol, acting as an additive to mix with tempo-oxidized cellulose nanofibrils (CNF), forming a transparent, flexible nanogenerator paper. The gas barrier property of CNF protects phosphorene against oxidation in ambient condition. The phosphorene in the hybrid paper is stable over six months even with ...

Nanostructured polymer-based piezoelectric and triboelectric materials and devices for energy harvesting applications

“…Other doping mechanisms, including the use of metallic inclusions, such as silver nanoparticles have also been reported [104]. Furthermore, future research of this field will benefit from progress in the discovery of new piezoelectric polymeric systems and crystalline phases, both synthetic and natural, that may find use in both piezoelectric and triboelectric energy harvesters, Cellulose, for example, is an abundant and common natural polymer can be found from cell walls of green plants, and it has recently been incorporated as piezo-or tribo-active materials for energy harvesting applications [105][106][107][108]. It is clear that advances in nanofabrication of polymeric materials and devices will likely continue to drive the field forward, particularly through precise control and/or enhancement of their relevant properties at the nanoscale.…”

Skin-touch-actuated textile-based triboelectric nanogenerator with black phosphorus for durable biomechanical energy harvesting

“…Ethanol suspension of HCOENPs (0.5 mg mL −1 ) was used here (see Supplementary Note 1 for the preparation details). Few layer BP was prepared from the pre-grinded BP by successive sonication (3 h) and centrifugation (10k rpm for 1 h), an ethanol solution of few layer BP (0.5 mg mL −1 ) was used in this work 44 .…”

Natural and Eco-Friendly Materials for Triboelectric Energy Harvesting

“…Products of processing of plants used to design TENGs: a cellulose/phosphorene hybrid TENG preparation and transparency demonstration. Reprinted with permission from Ref [72]…”