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Efficient broadband light absorption in thin-film a-Si solar cell based on double sided hybrid bi-metallic nanogratings
摘要： Thin film solar cells (TFSCs) suffer from poor light absorption due to their small thickness, which limits most of their practical applications. Surface plasmons generated by plasmonic nanoparticles offer an opportunity for a low-cost and scalable method to optically engineer TFSCs. Here, a systematic simulation study is conducted to improve the absorption efficiency of amorphous silicon (a-Si) by incorporating double sided plasmonic bi-metallic (Al–Cu) nanogratings. The upper pair of the gratings together with an antireflection coating are responsible for minimizing the reflection losses and enhancing the absorption of low wavelength visible light spectrum in the active layer. The bottom pairs are accountable for increasing the absorption of long wavelength photons in the active layer. In this way, a-Si, which is a poor absorber in the long wavelength region, is now able to absorb broadband light from 670–1060 nm with an average simulated absorption rate of more than 70%, and improved simulated photocurrent density of 22.30 mA cm?2, respectively. Moreover, simulation results show that the proposed structure reveals many other excellent properties such as small incident angle insensitivity, tunability, and remarkable structural parameters tolerance. Such a design concept is quite versatile and can be extended to other TFSCs.
关键词： amorphous silicon,Thin film solar cells,plasmonic nanoparticles,bi-metallic nanogratings,light absorption
更新于2025-09-23 15:21:01
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Thermal nanoimprint lithography based plasmonic nanogratings for refractive index sensing of polar solvents
摘要： This work illustrates a facile approach for the design of flexible plasmonic sensors using gold nanograting. The fabrication of surface plasmon resonance (SPR) coupled refractive index (RI) sensor is proposed to sense the various known RIs of polar solvents. Thermal nanoimprint lithography (T-NIL) is used to transfer the nanograting of the processed digital versatile discs (DVDs) through polydimethylsiloxane (PDMS) stamp to thermoplastic polymer coated flexible polyethylene terephthalate (PET) substrate. The gold nanograting sample was obtained after the subsequent deposition of the gold thin film of thickness 60 nm on top of polymer nanograting. The surface plasmon resonance (SPR) modes excited on gold-encrusted polymer nanograting appeared as a dip in the reflectance spectra measured at normal incidence under white light in air and liquid medium. We use refractive index calibration polar solvents [methanol (1.331), water (1.333), acetone (1.359), ethanol (1.361) and isopropanol (1.382)] to determine the refractive index sensitivity of our gold nanograting arrays. This produces a bulk refractive index sensitivity of 535 ± 47 nm/RIU. The real-time kinetic response demonstrates the stability of the sensor with respect to the time and reusability of the sensing chip for multiple measurements. Thus, we envisaged that our proposed sensor can be a potential candidate for the development of highly sensitive plamonic device.
关键词： Nanogratings,surface plasmon resonance (SPR),Thermal nanoimprint lithography (T-NIL),Plasmonic sensor,Polar solvents
更新于2025-09-23 15:19:57
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Exciton polaritons based on planar dielectric Si asymmetric nanogratings coupled with J-aggregated dyes film
摘要： Optical cavity polaritons, originated from strong coupling between the excitons in materials and photons in the con?ned cavities ?eld, have recently emerged as their applications in the high-speed low-power polaritons devices, low-threshold lasing and so on. However, the traditional exciton polaritons based on metal plasmonic structures or Fabry-Perot cavities suffer from the disadvantages of large intrinsic losses or hard to integrate and nanofabricate. This greatly limits the applications of exciton poalritons. Thus, here we implement a compact low-loss dielectric photonic – organic nanostructure by placing a 2-nm-thick PVA doped with TDBC ?lm on top of a planar Si asymmetric nanogratings to reveal the exciton polaritons modes. We ?nd a distinct anti-crossing dispersion behavior appears with a 117.16 meV Rabi splitting when varying the period of Si nanogratings. Polaritons dispersion and mode anti-crossing behaviors are also observed when considering the independence of the height of Si, width of Si nanowire B, and distance between the two Si nanowires in one period. This work offers an opportunity to realize low-loss novel polaritons applications.
关键词： exciton polaritons,dielectric Si asymmetric,TDBC J-aggregated dyes ?lm,nanogratings
更新于2025-09-16 10:30:52
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Indium‐rich InGaN/GaN solar cells with improved performance due to plasmonic and dielectric nanogratings
摘要： In this study, we propose an indium‐rich InGaN/GaN p‐i‐n thin‐film solar cell which incorporates a dual nanograting (NG) structure: Ag nanogratings (Ag‐NGs) on the backside of the solar cell and gallium nitride nanogratings (GaN‐NGs) on the frontside. Finite‐difference time‐domain (FDTD) simulation results show that the dual NG structure couples the incident sunlight to the plasmonic and photonic modes, thereby increasing the absorption of the solar cell in a broad spectral range. It is observed that the solar cells having the dual nanograting structures have a significant enhancement in light absorption as compared to cells having either no nanogratings or having only the frontside nanogratings or only the backside nanogratings. Analysis of light absorption in solar cells containing the dual NG structures showed that the absorption enhancement of longer wavelengths is mostly due to the Ag‐NGs on the backside and of shorter wavelengths is mostly due to the GaN‐NGs on frontside of the solar cell. The Jsc and power conversion efficiency (PCE) are calculated under AM1.5G solar illumination and are observed to be significantly enhanced due to the presence of optimized dual NG structures. While there is an increase in Jsc from 17.88 to 23.19 mA/cm2 (~30% enhancement), there is an increase in PCE from 15.49% to 20.24% (~31% enhancement) under unpolarized light (average of TM and TE). Moreover, the study of oblique light incidence shows significantly larger Jsc of the dual nanograting solar cells compared to the cells with no nanogratings.
关键词： broadband absorption,FDTD simulations,light trapping,surface plasmons,nanogratings,InGaN solar cells
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Compact Femtosecond Laser Direct Written Integrated Retarders Based on Embedded Nanogratings
摘要： Femtosecond Laser Direct Writing (FLDW) is a well-known rapid prototyping method to fabricate integrated optical circuits in glass chips. These circuits have been used to show various quantum information applications, using the states of photons as qubits. Generally, when transmitting information via single photons, it is desirable to make use of all possible degrees of freedom that this photon has to offer, in order to increase the amount of information transferred per photon. One of these degrees of freedom is the photon’s polarization. To make use of this degree of freedom, devices capable of manipulating the polarization are required. Various approaches for manipulating the polarization of photons in a FLDW circuit have been demonstrated before, of which some were used for quantum information applications. In our work, we present a novel method of polarization control using embedded nanogratings as waveplates. These nanogratings are highly birefringent self-assembled structures. Due to their relatively high form birefringence on the order of Δn = 10^-3, they can be used as a compact waveplate enabling further miniaturization of integrated optical circuits. The properties of these gratings can be altered by using different laser parameters during the inscription process. We have added various waveplates made of nanogratings into FLDW waveguides. We demonstrate their functionality as waveplates of different retardation and optical axis orientations using crossed polarizer birefringence measurements. Due to the chosen writing geometry, a full control over the direction of the optical axis can be achieved. The thickness of these structures is on the order of a few hundred micrometers. Former approaches for polarization control in FLDW circuits required structures in the range of millimetres to centimeters. Some of these approaches were limited in the achievable optical axis orientations. Our waveplates can be both used for classical applications and as single qubit quantum gates, which will be demonstrated. Waveplate structures usable as Hadamard, Pauli-x, Pauli-z and Pi/8th gates have been fabricated. The transferability to fibers will be discussed.
关键词： integrated optical circuits,polarization control,quantum information applications,waveplates,nanogratings,Femtosecond Laser Direct Writing
更新于2025-09-11 14:15:04
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Light absorption enhancement of plasmonic based photo-detector with double nanograting structure
摘要： This era of high speed photonic systems demands photo detectors to have large bandwidth, gain and improved light enhancement competence. Amongst the different light absorption enhancement methods being researched by the investigators, plasmonic has acquired increased attention in the last decades. Although single layer plasmonic supported metal semiconductor metal photo detector has been explored for higher light absorption efficiency, but exploration for double layer structure is lacking in literature. This paper presents performance of plasmonic based photodetector with double layer of nanogratings optimized at wavelength of 1.4 μm for night vision applications. Proposed design of plasmonic supported photodetector with double nanograting reports quenching factor of 92.14% and provides highest light enhancement with subwavelength aperture height of 60 nm. This can be credited to fact that both top and bottom layer of grating contributes to light trapping.
关键词： Surface plasmon polaritons (SPPs),Nanogratings,Nanomaterials,Plasmonics,Subwavelength aperture
更新于2025-09-11 14:15:04
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Enhanced Temperature-Tunable Narrow-Band Photoluminescence from Resonant Perovskite Nanograting
摘要： Tunable light-emitting nanostructures are prospective for reconfigurable compact optoelectronic devices. In this regard, halide perovskites are one of the most efficient class of materials, because of their outstanding electronic and optical properties as well as low cost of fabrication and nanostructuring. Here, we study the temperature-tunable reconfiguration of photonic modes in periodically nanostructured perovskite (MAPbI3) film probed by enhanced photoluminescence. We achieved the quality factors of resonances around 500 at wavelengths 750–760 nm. The experimental results are in well agreement with theoretical simulations. Our study reveals the origin of the emission enhancement from such kind of perovskite nanostructures and paves the way to highly directional, efficient, and tunable narrowband emission from optoelectronic devices.
关键词： Optoelectronic devices,Photoluminescence,Tunable light-emitting nanostructures,Halide perovskites,Nanogratings
更新于2025-09-04 15:30:14