Light Management with Nanostructures for Optoelectronic Devices

Abstract

Light management is of paramount importance to improve the performance of optoelectronic devices including photodetectors, solar cells, and light-emitting diodes. Extensive studies have shown that the efficiency of these optoelectronic devices largely depends on the device structural design. In the case of solar cells, threedimensional (3-D) nanostructures can remarkably improve device energy conversion efficiency via various light-trapping mechanisms, and a number of nanostructures were fabricated and exhibited tremendous potential for highly efficient photovoltaics. Meanwhile, these optical absorption enhancement schemes can benefit photodetectors by achieving higher quantum efficiency and photon extraction efficiency. On the other hand, low extraction efficiency of a photon from the emissive layer to outside often puts a constraint on the external quantum efficiency (EQE) of LEDs. In this regard, different designs of device configuration based on nanostructured materials such as nanoparticles and nanotextures were developed to improve the out-coupling efficiency of photons in LEDs under various frameworks such as waveguides, plasmonic theory, and so forth. In this Perspective, we aim to provide a comprehensive review of the recent progress of research on various light management nanostructures and their potency to improve performance of optoelectronic devices including photodetectors, solar cells, and LEDs. O ptoelectronic devices, such as photodetectors, solar cells, and light-emitting diodes (LEDs), are essentially light to electricity or vice versa energy conversion devices. Utilization of efficient optoelectronic devices cannot only produce clean energy but can also help with energy conservation. Recent extensive studies have shown that the efficiency of these optoelectronic devices largely depends on the device structural design. In the case of solar cells, which involve conversion from solar radiation to electricity, it has been discovered that nanostructures can remarkably improve the energy conversion efficiency via various light-trapping mechanisms. Therefore, a number of nanostructures including nanowires, nanopillars, nanoholes, and so forth were fabricated, and their effectiveness for photovoltaic (PV) performance improvement has been examined based on different material systems. Meanwhile, these optical absorption enhancement schemes can benefit photodetectors as well. It is worth pointing out that due to the different application scale requirement, low-cost approaches are desired for effective light management in PV applications. However, performance is the primary concern for photodetectors in most circumstances. On the other hand, a LED is a device that converts electrical energy to optical radiation. High quantum efficiency and photon extraction efficiency not only help energy conservation but also minimize the overheating of the device, thus prolonging its lifetime. In recent decades, numerous material systems and techniques were extensively studied to improve the internal quantum ...

One-step deposition of ZnO morphologies from single aqueous chemical bath prepared from reverse osmosis processed water

“…[15]. Here, we report deposition of all these morphologies from a single aqueous bath of tetra ammonium zinc complex Zn(NH 3 ) 4 2 þ within 1 h at above 80 1C.…”

“…Nowadays, various nanostructures of ZnO have attracted considerable attention due to their novel properties [3]. It is developed for a range of electronic, optoelectronic and photonic applications [4]. Being non-toxic it is also used as a diagnostic tool for cancers [5,6] and broadband UV-absorbers in pharmaceutical and cosmetic applications [7].…”

Evolution mechanism of mesoporous silicon nanopillars grown by metal-assisted chemical etching and nanosphere lithography: correlation of Raman spectra and red photoluminescence

“…Silicon nanostructures, including nanowires and nanopillars, are one of the most promising materials for applications in nanoscale electronics [1,2], photovoltaics and energy conversion [3][4][5], energy storage [6], optoelectronics [7,8], nanocapacitor arrays [9], biosensors [10,11], to name a few. Several studies on silicon nanostructures have been well documented over the last decade [12].…”

The Effect of a Sputtered Al-Doped ZnO Seed Layer on the Morphological, Structural and Optical Properties of Electrochemically Grown ZnO Nanorod Arrays

“…Due to this scattering phenomenon, an enhancement in the absorption is observed as a consequence of an increased optical path in the sample. 60 If the NRAs geometry is smaller than λ, then other mechanisms, like effective index of refraction gradient, are dominant. 60,61 A diminution in the optical transmittance is observed for small diameter ZnO NRAs due to the disordered grown direction of the nanorods compared with the ordered samples.…”

“…60 If the NRAs geometry is smaller than λ, then other mechanisms, like effective index of refraction gradient, are dominant. 60,61 A diminution in the optical transmittance is observed for small diameter ZnO NRAs due to the disordered grown direction of the nanorods compared with the ordered samples. 62,63 Moreover, multiple scattering shows a dependence on the length of the NR, particularly an increase in the scattering is observed for longer NRAs.…”