Broadband absorption enhancement in plasmonic nanoshells-based ultrathin microcrystalline-Si solar cells

Broadband PM6Y6 coreshell hybrid composites for photocurrent improvement and light trapping

Our research focuses on enhancing the broadband absorption capability of organic solar cells (OSCs) by integrating plasmonic nanostructures made of Titanium nitride (TiN). Traditional OSCs face limitations in absorption efficiency due to their thickness, but incorporating plasmonic nanostructures can extend the path length of light within the active material, thereby improving optical efficiency. In our study, we explore the use of refractory plasmonics, a novel type of nanostructure, with TiN as an example of a refractory metal. TiN offers high-quality localized surface plasmon resonance in the visible spectrum and is cost-effective, readily available, and compatible with CMOS technology. We conducted detailed numerical simulations to optimize the design of nanostructured OSCs, considering various shapes and sizes of nanoparticles within the active layer (PM6Y6). Our investigation focused on different TiN plasmonic nanostructures such as nanospheres, nanocubes, and nanocylinders, analyzing their absorption spectra in a polymer environment. We assessed the impact of their incorporation on the absorbed power and short-circuit current (Jsc) of the organic solar cell.

Over 65% Sunlight Absorption in a 1 μm Si Slab with Hyperuniform Texture

Thin, flexible, and invisible solar cells will be a ubiquitous technology in the near future. Ultrathin crystalline silicon (c-Si) cells capitalize on the success of bulk silicon cells while being lightweight and mechanically flexible, but suffer from poor absorption and efficiency. Here we present a new family of surface texturing, based on correlated disordered hyperuniform patterns, capable of efficiently coupling the incident spectrum into the silicon slab optical modes. We experimentally demonstrate 66.5% solar light absorption in free-standing 1 μm c-Si layers by hyperuniform nanostructuring for the spectral range of 400 to 1050 nm. The absorption equivalent photocurrent derived from our measurements is 26.3 mA/cm², which is far above the highest found in literature for Si of similar thickness. Considering state-of-the-art Si PV technologies, we estimate that the enhanced light trapping can result in a cell efficiency above 15%. The light absorption can potentially be increased up to 33.8 mA/cm² by incorporating a back-reflector and improved antireflection, for which we estimate a photovoltaic efficiency above 21% for 1 μm thick Si cells.

Research Progress of Plasmonic Nanostructure-Enhanced Photovoltaic Solar Cells

Enhancement of the electromagnetic properties of metallic nanostructures constitute an extensive research field related to plasmonics. The latter term is derived from plasmons, which are quanta corresponding to longitudinal waves that are propagating in matter by the collective motion of electrons. Plasmonics are increasingly finding wide application in sensing, microscopy, optical communications, biophotonics, and light trapping enhancement for solar energy conversion. Although the plasmonics field has relatively a short history of development, it has led to substantial advancement in enhancing the absorption of the solar spectrum and charge carrier separation efficiency. Recently, huge developments have been made in understanding the basic parameters and mechanisms governing the application of plasmonics, including the effects of nanoparticles' size, arrangement, and geometry and how all these factors impact the dielectric field in the surrounding medium of the plasmons. This review article emphasizes recent developments, fundamentals, and fabrication techniques for plasmonic nanostructures while investigating their thermal effects and detailing light-trapping enhancement mechanisms. The mismatch effect of the front and back light grating for optimum light trapping is also discussed. Different arrangements of plasmonic nanostructures in photovoltaics for efficiency enhancement, plasmonics' limitations, and modeling performance are also deeply explored.

Distributed silicon nanoparticles: an efficient light trapping platform toward ultrathin-film photovoltaics

In this paper, a new architecture comprising silicon nanoparticles inside a hole transport layer laid on a thin silicon layer is proposed to develop ultrathin film solar cells. Using generalized Mie theory, a fast analytical approach is developed to evaluate the optical absorption of the proposed structure for various geometries, polarizations and angles of incidence. The analytical results are verified through comparison with full-wave simulations, illustrating a reasonable agreement. The electrical performance of a distributed silicon nanoparticle solar cell is determined for selected configurations. To be able to predict the light-trapping in a solar cell comprising randomly distributed nanospheres, a new technique based on probability theory is developed and validated through comparison with the simulation results. Both analytical and numerical results show that the excited Mie resonant modes in the proposed structure lead to a significant enhancement in both absorption and the photo-generated current, in comparison to a conventional silicon solar cell with an equivalent volume of the active layer. In the case of random distributions, other advantages, including the simple fabrication process, indicate that the cell is a promising structure for ultrathin photovoltaics.

Plasmon-Enhanced Sunlight Harvesting in Thin-Film Solar Cell by Randomly Distributed Nanoparticle Array

In this paper, a randomly distributed plasmonic aluminum nanoparticle array is introduced on the top surface of conventional GaAs thin-film solar cells to improve sunlight harvesting. The performance of such photovoltaic structures is determined through monitoring the modification of its absorbance due to changing its structural parameters. A single Al nanoparticle array is integrated over the antireflective layer to boost the absorption spectra in both visible and near-infra-red regimes. Furthermore, the planar density of the plasmonic layer is presented as a crucial parameter in studying and investigating the performance of the solar cells. Then, we have introduced a double Al nanoparticle array as an imperfection from the regular uniform single array as it has different size particles and various spatial distributions. The comparison of performances was established using the enhancement percentage in the absorption. The findings illustrate that the structural parameters of the reported solar cell, especially the planar density of the plasmonic layer, have significant impacts on tuning solar energy harvesting. Additionally, increasing the plasmonic planar density enhances the absorption in the visible region. On the other hand, the absorption in the near-infrared regime becomes worse, and vice versa.

Plasmonic Resonances of Metal Nanoparticles: Atomistic vs. Continuum Approaches

The fully atomistic model, ωFQ, based on textbook concepts (Drude theory, electrostatics, quantum tunneling) and recently developed by some of the present authors in Nanoscale, 11, 6004-6015 is applied to the calculation of the optical properties of complex Na, Ag, and Au nanostructures. In ωFQ, each atom of the nanostructures is endowed with an electric charge that can vary according to the external electric field. The electric conductivity between nearest atoms is modeled by adopting the Drude model, which is reformulated in terms of electric charges. Quantum tunneling effects are considered by letting the dielectric response of the system arise from atom-atom conductivity. ωFQ is challenged to reproduce the optical response of metal nanoparticles of different sizes and shapes, and its performance is compared with continuum Boundary Element Method (BEM) calculations.

Enhanced plasmonic photovoltaic using embedded novel gear-shaped nanoparticles

In this paper, novel gear-shaped nanoparticles are introduced for the first time to enhance the photovoltaic (PV) efficiency. This has been achieved via increasing the overall power absorption by the PV semiconductor material in both visible and near-infrared ranges. The modes of the new gear-shaped nanoparticles are investigated. A parametric study has been performed which demonstrates how the design parameters of the proposed nanoparticles can be engineered for best overall power absorption within a Si surrounding medium. A figure of merit (FoM) is defined that takes into account all objectives. An optimization technique is applied to obtain the optimum set of the gear's dimensions, penetration depth, and periodicity for the maximum possible FoM. The optimum gear-shaped nanoparticles design offers 48% enhancement in the FoM if compared with a bare Si block with no nanoparticles and 7% enhancement over the conventional disk-shaped nanoparticles. The enhancement gained by the embedded gear-shaped nanoparticles on the J-V characteristics of the PV is also studied, and the effects of changing the dimensions and the position of nanoparticles on the J-V characteristics enhancement are investigated.

Polarization dependence of plasmon enhanced fluorescence on Au nanorod array

The spatial anisotropy of Au nanorod results in two distinct orientational modes by which the polarization orientation dependence of excitation and emission can be studied. In this work, a periodical distributed metallic nanostructure substrate, which contains an array of Au nanorods, is synthesized, and the polarization dependence of the plasmon enhanced fluorescence effect is investigated experimentally and numerically. It is found that the fluorescence emission enhancement of organic probe fluorophores located at the surface of Au nanorods depends on the polarization angle very sensitively. Different polarization orientations of the excitation light result in very different enhancement effects. As a result, the change of the polarization orientation of the excitation light can be a sensitive marker of surface chemistry and other possible practical applications.