Alternating the Output of a CdS Nanowire Nanogenerator by a White‐Light‐Stimulated Optoelectronic Effect

Abstract

Energy shortage and global warming are two grand challenges to human beings in the 21st century. The development of clean alternative energies and emission control of gases, such as CO 2 , have become most-urgent research fields. For the development of clean alternative energies, a wide range of approaches has been explored, including solar cells, [1] fuel cells, [2] and thermoelectric devices.[3] Solar cells, fuel cells, and thermoelectric devices convert optical, chemical, and thermal energies to electrical energy, respectively. Generation of electric energy from conversion of mechanical energy is of great interest owing to its abundance and unique fit for some applications. Recently, ZnO-nanowire (NW)-array-based piezoelectric nanogenerators have been demonstrated to convert mechanical energy to electricity by utilizing the coupling effect of the semiconducting and piezoelectric properties of ZnO. [4][5][6] Further exploration of this piezotronic concept [7] has led to the development of a wide variety of ZnO-NW-based piezotronic devices, such as piezoelectric field effect transistors, [8] nanoforce sensors, [8] and gate diodes.[9]More recently, CdS NWs were also successfully demonstrated for piezoelectric nanogenerators.[10] As another member in the wurtzite family, CdS is a piezoelectric, semiconducting, [11] and optoelectric [12] material with a direct energy band gap of about 2.5 eV [13] (corresponding to an on-set absorption of 500 nm). A wide range of 1D CdS nanostructures such as NWs, [14] NW arrays, [15] nanobelts, [16] nanotubes, [17] nanocombs, [18] and tetrapods, [19] have been synthesized by wet-chemistry or vapor-phase processes. The photon-induced conduction of 1D CdS nanostructures has also been demonstrated and studied. [20] A wide variety of 1D CdS nanostructure-based optoelectronic devices, such as photoconductors, [20] waveguides, [21] lasers, [22] logic gates, [23] field emitters, [24] and field-effect transistors (FETs) [25,26] have been developed.

One-dimensional ZnO nanostructures: Solution growth and functional properties

“…Following this initial discovery, both direct current [23,499,500] and alternating current [24] ZnO nanogenerators have been developed. In addition, nanogenerators based on other materials, such as GaN nanowires [501][502][503], InN nanowires [504], AlGaN nanocones [505], CdS nanowires [506], ZnO/ZnS heterojunction nanowires [507], lead zircornia titanates (PZT) nanofibers [508], nanoribbons [509][510][511][512][513], nanotubes [514], and single crystalline nanowires [515], BaTiO 3 nanowires [516], NaNbO 3 nanowires [517], and poly(vinylidene fluoride) (PVDF) nanofibers [518,519], have shown promising potential for enhancing nanogenerator performance. Consequently, a worldwide effort has been launched in this regard, forming a new research field in nanotechnology and energy science [520].…”

One-pot sonochemical synthesis of CdS nanoparticles: photocatalytic and electrical properties

“…Among the II-VI semiconductors, CdS is one of the first semiconductors to be discovered and is probably one of the most important electronic and optoelectronic materials, with prominent applications in nonlinear optical devices, flat panel displays, light emitting diodes, lasers, logic gates, transistors, etc [1][2][3]. Many studies have focused on CdS because of its high photosensitivity and potential application in photoconducting cells and a variety of optoelectronic conversion devices including photodetectors and thin film solar cells [4].…”

Fabrication of zinc oxide nanoneedles on conductive textile for harvesting piezoelectric potential

“…When an external load was employed on ZnO NNs by AFM tip then due to deformation/ bending of NNs positive (V + ) and negative (V − ) charges created along the stretched and compressed sides of ZnO NNs respectively. If tip is touching compressed or stretched sides of the NNs, then it will only cause forward or reverse bias Schottky junction [27][28]. Figure 6 (c) showing the top view of ZnO NN model, where due to the deformation/ bending polarization has been occurred along the ZnO NN [5].…”