Two-dimensional crystals with a wealth of exotic dimensional-dependent properties are promising candidates for next-generation ultrathin and flexible optoelectronic devices. For the first time, we demonstrate that few-layered InSe photodetectors, fabricated on both a rigid SiO2/Si substrate and a flexible polyethylene terephthalate (PET) film, are capable of conducting broadband photodetection from the visible to near-infrared region (450-785 nm) with high photoresponsivities of up to 12.3 AW(-1) at 450 nm (on SiO2/Si) and 3.9 AW(-1) at 633 nm (on PET). These photoresponsivities are superior to those of other recently reported two-dimensional (2D) crystal-based (graphene, MoS2, GaS, and GaSe) photodetectors. The InSe devices fabricated on rigid SiO2/Si substrates possess a response time of ∼50 ms and exhibit long-term stability in photoswitching. These InSe devices can also operate on a flexible substrate with or without bending and reveal comparable performance to those devices on SiO2/Si. With these excellent optoelectronic merits, we envision that the nanoscale InSe layers will not only find applications in flexible optoelectronics but also act as an active component to configure versatile 2D heterostructure devices.

sodium ion batteries are almost on the verge of commercialization and investigation is still underway to make them widely available for many applications. [10][11][12] Regardless of the change, batteries have failed to satisfy consumer needs in many aspects, especially in terms of next-generation high power applications. [13] The emerging high power devices can neither be powered by state-of-the-art lithium ion batteries nor by low cost sodium ion batteries due to the limited power of such batteries, driven by slow intercalation and deintercalation kinetics. [7,14,15] Although high power electrochemical double layer capacitors (EDLCs) can supply the requisite power, they are inferior to batteries in supplying the necessary energy density. [7,13,[16][17][18][19] Hybrid capacitors (HCs) are a new class of energy storage device that bridge the gap between batteries and EDLCs by delivering high energy at high power without sacrificing the stability, and thereby fulfilling the needs of high power applications. [20,21] HCs operate by the following dual mechanism that occurs simultaneously in two asymmetric electrodes: (i) intercalation/deintercalation of cations delivering high energy and (ii) surface adsorption and desorption of anions supplying high power and stability. Successful intercalation/deintercalation of sodium ions into a suitable electrode paves the way for development of novel, low cost sodium hybrid capacitor systems. [22][23][24] Sodium hybrid capacitors with the right combination of insertion and adsorption electrodes that are kinetically well balanced can retain high energy density and power density with robust durability. [21,[24][25][26] Various intercalation-based electrodes, including layered oxides, sulfates, metal oxides, phosphates, fluorophosphates, hard carbons, red phosphorous, and much more, have been investigated for sodium ion batteries. [27][28][29] In general, sodium insertion electrodes suffer from poor sodium insertion kinetics and poor structural integrity due to the quick transition metal loss and large lattice strain that occur during sodium insertion, thereby restricting their application in hybrid capacitors. However, sodium super ionic conductor (NASICON) structured-NaTi 2 (PO 4 ) 3 (NTP)-insertion materials are considered to be the best choice for hybrid capacitor application due to their high ionic conductivity, quick sodium insertion into their structure due to their ultrafast sodium ion kinetics, and structural stability. [12,[30][31][32] Further, sodium ions can be inserted into NTP materials without compromising their structural integrity, which could further improve their energy retention for longer Hybrid capacitors, especially sodium hybrid capacitors (NHCs), have continued to gain importance and are extensively studied based on their excellent potential to serve as advanced devices for fulfilling high energy and high power requirements at a low cost. To achieve remarkable performance in hybrid capacitors, the two electrodes employed must be superior with enhanced charg...

Lithium–sulfur batteries (Li–S) are considered the most promising systems for next-generation energy storage devices due to their high theoretical energy density and relatively low cost.

Flexible piezoelectric generators constructed using one-dimensional nanostructures are well known for their efficient energy harvesting. Herein, we have fabricated a flexible piezoelectric energy harvester (PEH) consisting of a single 0.65Pb(Mg 1/3 Nb 2/3 )O 3 -0.35PbTiO 3 nanowire (PMN-PT NW) using a facile transferring approach onto a Au electrode-patterned plastic substrate. The well-developed device effectively harvested the maximum output signals (9 mV and 1.5 nA) originating from a single PMN-PT nanowire under mechanical bending/unbending motions. The designed PEH is also expected to be utilized as a versatile tool to evaluate the performance of a one-dimensional nanostructure.