Enhancement of Schottky Junction Silicon Solar Cell with CdSe/ZnS Quantum Dots Decorated Metal Nanostructures

Recently, in the solar energy society, several key technologies have been reported to meet a grid parity, such as cost-efficient materials, simple processes, and designs. Among them, the assistive plasmonic of metal nanoparticles (MNPs) integrating with the downshifting on luminescent materials attracts much attention. Hereby, Si-based Schottky junction solar cells are fabricated and examined to enhance the performance. CdSe/ZnS quantum dots (QDs) with different gold nanoparticles (Au NPs) sizes were incorporated on a Si light absorbing layer. Due to the light scattering effect from plasmonic resonance, the sole Au NPs layer results in the overall enhancement of Si solar cell’s efficiency in the visible spectrum. However, the back-scattering and high reflectance of Au NPs lead to efficiency loss in the UV region. Therefore, the QDs layer acting as a luminescent downshifter is deployed for further efficiency enhancement. The QDs layer absorbs high-energy photons and re-emits lower energy photons in 528 nm of wavelength. Such a downshift layer can enhance the overall efficiency of Si solar cells due to poor intrinsic spectral response in the UV region. The optical properties of Au NPs and CdSe QDs, along with the electrical properties of solar cells in combination with Au/QD layers, are studied in depth. Moreover, the influence of Au NPs size on the solar cell performance has been investigated. Upon decreasing the diameters of Au NPs, the blueshift of absorbance has been observed, cooperating with QDs, which leads to the improvement of the quantum efficiency in the broadband of the solar spectrum.

Fabrication of the Cu2ZnSnS4 Thin Film Solar Cell via a Photo-Sintering Technique

Alternative photo-sintering techniques for thermal annealing processes are used to improve the morphology, layer properties, and enhance solar cell performance. The fast, nontoxic, low cost, and environmentally friendly characteristics of Cu2ZnSnS4 have led to its consideration as an alternative potential absorber layer in copper indium gallium diselenide thin film solar cells. This work investigates the photo-sintering process for the absorber layer of Cu2ZnSnS4 solar cells. A Cu2ZnSnS4 layer was grown by hot-injection and screen-printing techniques, and the characteristics of the photo-sintered Cu2ZnSnS4 layer were evaluated by X-ray Diffraction, Raman spectroscopy, Energy dispersive X-ray analysis, Ultraviolet-visible spectroscopy, and field emission scanning electron microscopes. Overall, the optimal composition was Cu-poor and Zn-rich, without a secondary phase, estimated optical band-gap energy of approximately 1.6 eV, and enhanced morphology and kesterite crystallization. Using an intensity pulse light technique to the CZTS layer, fabrication of the solar cell device demonstrated successfully, and the efficiency of 1.01% was achieved at 2.96 J/cm2.

Deleterious Effects of Halides and Solvents on the Integrity of Copper Iodide Hole Extraction Layers in Hybrid Perovskite Photovoltaics

Copper iodide (CuI) is a promising material for use as a hole transport layer in perovskite solar cells due to its optical transparency, low-cost fabrication, and efficient electronic (hole) conductivity. Various reports of perovskite solar cells that utilize CuI have shown impressive solar cell performance and improved device stability. Despite these observations, we found no clear experimental evidence that the CuI hole transport layer is retained in perovskite p-i-n solar cells after device fabrication. Using powder X-ray diffraction (PXRD), UV-vis spectroscopy, and impedance spectroscopy, we studied how each of the components present in the precursor solution for fabricating the perovskite active layer impacts the integrity of CuI films. Based on these data, we establish the deleterious effects of halide ions and solvents such as dimethyl sulfoxide (DMSO). We also show that we can fabricate stable CuI material in situ during perovskite deposition by taking advantage of a known redox chemistry of Cu(II)/Cu(I) and halides.

Amorphous Silicon Thin Film Deposition for Poly-Si/SiO2 Contact Cells to Minimize Parasitic Absorption in the Near-Infrared Region

Tunnel oxide passivated contact (TOPCon) solar cells are key emerging devices in the commercial silicon-solar-cell sector. It is essential to have a suitable bottom cell in perovskite/silicon tandem solar cells for commercial use, given that good candidates boost efficiency through increased voltage. This is due to low recombination loss through the use of polysilicon and tunneling oxides. Here, a thin amorphous silicon layer is proposed to reduce parasitic absorption in the near-infrared region (NIR) in TOPCon solar cells, when used as the bottom cell of a tandem solar-cell system. Lifetime measurements and optical microscopy (OM) revealed that modifying both the timing and temperature of the annealing step to crystalize amorphous silicon to polysilicon can improve solar cell performance. For tandem cell applications, absorption in the NIR was compared using a semitransparent perovskite cell as a filter. Taken together, we confirmed the positive results of thin poly-Si, and expect that this will improve the application of perovskite/silicon tandem solar cells.

Fabrication of (ZnO)x: (Cu)1-x/PSi Solar Cell Using Laser Induced Plasma Technique

Fabrication of PSi is generated successfully depending upon photo-electrochemical etching process. The purpose is to differentiate the characterization of the PSi monolayer based on c-silicon solar cell compared to the bulk silicon alone. The surface of ordinary p-n solar cell has been reconstructed on the n-type region of (100) orientation with resistivity (3.2.cm) in hydrofluoric (HF) acid at a concentration of 2 ml was used to in order to enhance the conversion efficiency with 10-minute etching time and current density of 50 mA/cm2, The morphological properties (AFM) as well as the electrical properties have been investigated (J-V). The atomic force microscopy investigation reveals a rugged silicon surface with porous structure nucleating during the etching process (etching time), resulting in an expansion in depth and an average diameter of (40.1 nm). As a result, the surface roughness increases. The electrical properties of prepared PS, namely current density-voltage characteristics in the dark, reveal that porous silicon has a sponge-like structure and that the pore diameter increases with increasing etching current density and the number of shots increasing this led that the solar cell efficiency was in the range of (1-2%), resulting in improved solar cell performance.

Computer simulations of solar cells based on silicon/boron phosphide selective contacts

Silicon solar cells with selective contacts based on boron phosphide (BP) demonstrate a high potential according to simulation. However, the influence of defects created at the BP/Si interface during BP deposition is a critical issue for solar cell performance. The computer simulations were performed to understand how the defects in the near-surface region and at the interface affect the photovoltaic properties. Calculations of the dependence of the characteristics of solar cells on parameters such as the density of interface states, the concentration of defects in the near-surface region, and its width were made.

Enhanced Perovskite Solar Cell Performance by Adding Magnesium Acetate Using Two-Step Spin-Coating Method

The poor stability of perovskite materials is a problem of concern in commercialization. In this study, we investigated the doping of magnesium cations (Mg2+) in PbI2 to improve the stability and efficiency of perovskite solar cells. The doping effect of Mg2+ can increase the crystallization rate. The perovskite film fabricated structure consists of ITO/TiO2/perovskite/CuO. The fabrication method used is a two-stage spin coating. The concentrations of MgAc2 were used 0, 0.75, 1, and 1.25 mg ml−1. The characterizations used are XRD (X-Ray Diffraction), UV-Vis, SEM-EDX. While the performance of solar cells is measured using a solar simulator. The XRD pattern shows that the sample has a crystal structure of MAPbI3, PbI2, and CuO phases. The MAPbI3 lattice parameter increased with increasing Mg acetate concentration. The grain size of the perovskite layer is between 5 - 15 μm, with a thickness of about 30 μm. The efficiency of perovskite solar cells increases with the increasing concentration of MgAc2.