This PDF file contains the front matter associated with SPIE Proceedings Volume 12763, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

Metal halide perovskite materials have attracted great attention owing to their fascinating optoelectronic characteristics and low-cost fabrication via facile solution processing. One of the potential applications of these materials is to employ them as color-conversion layers (CCLs) for visible blue light to achieve micro-LED full-color displays. However, obtaining thick perovskite films and fine patterns to realize complete color conversion and vivid display performance is still very challenging. Here, we elaborately addressed above issues and successfully demonstrated efficient blue-to-green photoconversion based on perovskite materials and applied in full color micro-LED displays.

Photonic nanostructures have achieved nanoscale optical field modulation and ultra-low refractive index effects that traditional thin film materials cannot reach, providing a new direction for optical management and carrier management of photovoltaic devices. Dielectric nanostructures can reduce the surface light reflection of photovoltaic devices, similar to traditional antireflection films. Therefore, dielectric nanostructures are usually equivalent to the equivalent refractive index theory at the macro level. However, the macroscopic refractive index equivalent cannot reflect the manipulation ability of nanoscale light fields, and the influence of the nanoscale light field distribution on the photo-carrier generation and transport is usually ignored. Here, we introduce the self-assembly process of dielectric nanostructures on photovoltaic devices, which may lead to the controllable assembly of the density and number of layers on polycrystalline silicon solar cells. Based on this strategy, we investigate the enhancement effect of SiO2 nanosphere coating on textured silicon solar cells by systematically changing assembly conditions. Research has found that tightly packed SiO₂ nanosphere monolayers generate a maximum relative efficiency improvement of 9.35%. This efficiency increase is attributed to the simultaneous enhancement of short-circuit current density and fill factor, which is different from the antireflection effect reported previously. Further, through semiconductor simulations, we theoretically analyzed the impact of nanoscale light focusing on the performance of photovoltaic devices. We explored the reasons for the changes in photocurrent, fill factor, and efficiency, providing ideas for more efficient nanoscale light focusing design and improving the performance of photovoltaic devices in the future.

Interface plays an important role in photovoltaic devices, due to the existence of surface defects and surface dangling bonds of semiconductor materials. For photovoltaic devices, defects on the surface of semiconductor materials can lead to the recombination of charge carriers at the interface and hinder the transport of carriers in the device, resulting in the degradation of device performance. We presented a simple and efficient method of interface treatment by oxygen plasma for PEDOT:PSS/silicon hybrid solar cell. Compared to the cell without oxygen plasma treatment, the cell with oxygen plasma treatment revealed a significant increase in power conversion efficiency (PCE), which resulted in interface control by oxygen plasma control can be able to effectively optimize the performance of organic-silicon hybrid solar cell.

The optical properties of the methylammonium lead iodide (CH₃NH₃PbI₃) - Germanium (Ge) heterojunction with a layer of periodical nanoparticles was investigated to achieve broadband light harvesting by 3D Finite Element Method (FEM). The constructed heterojunction device showed a broad bandwidth from 300nm to 1600nm. Under the AM(1.5) illumination, the maximal energy absorbed by the heterojunction device was 776.64W/m² after optimizing thickness of perovskite and Ge, as well as radius of metallic or dielectric nanospheres (Au, Ag, Al, Si₃N₄, TiO₂, Ta₂O₅). The improved optical performance was further demonstrated by comparing calculated electric fields and charge carrier generation rates of the optimized heterojunction with periodical nanoparticles layer with that of corresponding flat device.

We are investigating the improvement of the precision of the means of measurement to determine if it is possible to have sufficient sensitivity to the detection of the effects of elementary particles which would be characteristic of dark matter. A particle has been proposed and is called axion. There would be an interaction between the axions and the photons using the Primakoff effect under strong magnetic field. Radio frequencies from 460 to 810 MHz would be assumed to be suitable for the mass of the axion, if it exists. It is then interesting to focus on the piezoaxionic effect. If the frequency of the axions could match the natural frequency of a normal mode bulk acoustic of a piezoelectric crystal, one would expect the piezoaxionic effect to occur. One could then rely on the piezoelectric effect to observe the variations on the resonant frequency which can be read out electrically using the best piezoelectric materials. Through this example of development and applications in detection, we propose to decrypt this subject and to show how multidisciplinary skills are necessary to hope that small fluctuations can be detectable.

Resonant beam charging (RBC) is a promising alternative to traditional wireless power technologies (WPT) considering the safety and long-range power transmission parameters. RBC has an excellent feature of self-alignment of an optical beam to make a strong connection between transmitter and receiver using retroreflectors. However, there are certain limitations in selecting an appropriate retroreflector considering the receiver size, Photovoltaic (PV) cell efficiency, and wide field of view for mobile receiver charging. The current investigation showcases a promising configuration of a practical receiver for optical wireless charging applications. The receiver incorporates a small 2 mm ball lens retroreflector with refractive index 1.967 at 1060 nm to establish a resonant cavity. The ball lens has highly reflection (HR) coating on the rear side to achieve a sufficient reflective signal and an anti-reflection (AR) coating on the front side to avoid surface reflections. This coated small ball lens features a wide field of view (FOV) upon using a large beam diameter, making it ideal to be used in optical receiver for mobile receiver charging. The performance of proposed receiver is evaluated using a semiconductor optical amplifier (SOA) as a gain medium operating in a bidirectional scheme at a center wavelength of 1060 nm. The proposed receiver model can potentially enhance the illumination area on the photovoltaic receiver, thereby increasing its efficiency. To validate the performance of the proposed model, a GaSb PV cell is used in the scheme, which ensures a peak efficiency of 25%.

In this study, HTL optimisation techniques have been used to analyse a double halide perovskite (which is lead-free) Cs₂NaGaBr₆ n-i-p solar cell in order to improve photovoltaic performance. A robust solar cell modeling tool called SCAPS- 1D was used for all of the simulations. The suggested photovoltaic design uses a double perovskite material. With a bandgap of 1.762 eV, Cs₂NaGaBr₆ is a direct band gap halide double perovskite material that is extremely close to organicinorganic perovskite material. With an improved hole transport layer (HTL) doping (1×10¹⁸ cm^-3–1×10²² cm^-3), the proposed solar cell had a better efficiency of 26.19%. Additionally, J_sc, V_oc, FF, and PCE (η) have all been examined as photovoltaic performance parameters. In order to create effective Pb-free perovskite for solar applications, the proposed device may be used.

Nanomaterials and nanotechnology have a pivotal role in reducing the footprint of target devices in many fields, in particular electronics and optics. The design of solar cells for meeting energy needs has also been taking advantage of such advancements in nanotechnology. One of the emerging types of solar cells is perovskite solar cells, which are not only cheap but efficient as well. There has been a lot of progress made in their design based on materials and structure. The continuous endeavors for further reduction of the device cost for large-scale deployment have led to a Hole Transparent Layer (HTL)-free structure with carbon electrodes instead of noble metals, as the work function of carbon is close to that of gold. The device layers, including the absorber and Electron Transport Layer (ETL), hold fundamental importance for an HTL-free design where TiO2 has been a very common material for ETL in perovskite solar cells, but it offers low conductivity and is susceptible to photo-catalysis on exposure to UV light. Therefore, we have investigated different materials, including WS₂ (BG: 1.8 eV), WO3 (BG: 2.6 eV), ZnSe (BG: 2.82 eV), ZnO (BG: 3.3 eV) for being suitable alternatives to TiO₂ (BG: 3.2 eV) as an ETL material. The device structure follows the configuration FTO/ETL/IDL/CH₃NH₃PbI₃/carbon. The optimization of different design parameters, including layer thicknesses, doping concertation, carrier mobility, diffusion length, and operating temperature, has been carried out. The device with ETL made of ZnSe yielded the best results as J_sc of 24.77 mA/cm², V_oc of 1.25 V, FF of 86.29%, and a PCE of 26.76% were obtained.

A wideband metasurface that is capable of absorbing more than 90% of electromagnetic energy is presented. The performance of the design is validated through numerical simulations for the materials including Niobium-nitride (NbN), Hafnium-nitride (HfN) and Tantalum nitride (TaN) for their broadband absorption behavior. We have employed a symmetric, square-structured unit-cell assuming subwavelength dimensions, where the spacer layers are of SiO₂ or Al₂O₃. In general, the excitation of localized electromagnetic resonances (in the top layer and the cavity), controls the devices’ absorption mechanism and is a strong function of the geometry of the top metal layer and the thickness of the dielectric layer. The meta-absorber is a periodic array of patches comprising of refractory-metal nitrides top on a thin dielectric layer over a highly reflecting thick layer. The highest values of absorption with silica as spacer for TaN-, HfN- and NbN-based subwavelength absorbers are 99.90%, 98.79% and 99.66%, at peak wavelengths of 549 nm, 584 nm and 664 nm, respectively. The average values of absorption obtained over the range 300 to 2500 nm are 89.10%, 91.71% and 79.84%, respectively. On the other hand, the peak absorption values with Al₂O₃ spacer for TaN-, HfN- and NbN-based designs are 96.12%, 96.93% and 99.99% at peak wavelengths of 338 nm, 349 nm and 330 nm, respectively. The spectral location of resonance does not shift significantly when light is incident at different angles and the average of the absorption remains higher than 84% for an incident angle of 70°. Furthermore, the design is absolutely insensitive to the change of polarization. The presented design has unit impedance at peak absorption wavelengths. Thus, the presented design offers all the favorable characteristics of an ideal absorber.