This study investigates the effects of chemical etching for anti-glare (AG) treatment and the subsequent deposition of a TiZrO2/SiO2 double-layer anti-reflection (AR) coating on glass surfaces. The AG treatment was performed using ammonium fluoride in gel form via screen printing, followed by electron beam deposition of SiO2/TiZrO2 layers. The surface roughness, optical transmittance, and refractive index were analyzed. The results revealed that while the surface roughness increased with larger screen patterns during the AG treatment, it was reduced by the deposition of the AR layers. Additionally, the gloss caused by external light was higher with lower surface roughness, but it was effectively reduced by the AR coating. The optical reflectance showed minimal changes during the AG treatment, remaining similar to that of bare glass substrates. However, the AR coating significantly decreased reflectance. The combination of AG treatment and AR coating improved optical transmittance and reduced gloss, making this method beneficial for enhancing visibility in automotive displays. The findings suggest that this approach can mitigate the impact of external light and improve the clarity of displayed information, making it suitable for automotive display applications.
In this study, oxide/metal/oxide-type transparent electrodes based on Al and ZnO were investigated. Thin films of these materials were sputter-deposited at room temperature. To evaluate the thickness dependence of the oxide layers, the top and bottom ZnO layers were varied in the range of 5~80 nm and 2.5~20 nm, respectively. When the thicknesses of the top and bottom ZnO layers were fixed at 30 nm and 2.5 nm, a maximum transmitance of 66% and sheet resistance of 16.5 Ω/□ were achieved, which is significantly improved compared with the Al layer without top and bottom ZnO layers showing a maximum transmitance of 44.3% and sheet resistance of 44 Ω/□.
We fabricated 1-D and 2-D diffraction gratings of SiOx anti-reflection (AR) film grown on a quartz substrate and integrated them into a c-Si photovoltaic (PV) submodule. The light-trapping effect of the resulting submodules was studied in terms of the oblique optical incident angle, θi. As the θi increased, solar conversion efficiency, η, was improved as expected by the increased optical transmission caused by the grating. For θi≤30°, the relative solar conversion efficiency, Δη, of a 1-D SiOx (t=300 nm) grating, compared to that of a flat SiOx AR-coated integrated PV submodule, was improved very little, with a small variation of within 2%, but increased markedly for θi≥40°. We observed a change of Δη as large as 10.7% and 9.5% for the SiOx grating of period t=800 nm and 1200 nm, respectively. For a 2-D SiOx (t=300 nm) grating integrated PV submodule, however, the optical trapping behavior was similar in terms of θi but its variation was small, within ±1.0%.
DSSCs (dye-sensitized solar cells) based on TiO2/SiO2 multi layer AR (anti-reflection) coating on the outer glass FTO (fluorine-doped tin oxide) substrate are investigated. We have coated an AR layer on the surface of a DSSCs device by using an IAD (ion beam-assisted deposition) system and investigated the effects of the AR layer by measuring photovoltaic performance. Compared to the pure FTO substrate, the multi layer AR coating increased the total transmittance from 67.4 to 72.9% at 530 nm of wavelength. The main enhancement of solar conversion efficiency is attributed to the reduction of light reflection at the FTO substrate surface. This leads to the increase of Jsc and the efficiency improvement of DSSCs.
Anti-reflective (AR) thin film was fabricated on a glass substrate by sol-gel method. The coating solution was synthesized with TEOS (tetraethlyorthosilicate) and poly ethylene glycol (PEG, 4.0 wt%). As the withdrawal speed of coating was changed from 0.1 mm/sec to 0.3 mm/sec, the thickness and refractive index of prepared thin films were changed. The reflectance and transmittance of coating glass fabricated by the withdrawal speed of 0.1 mm/sec were 0.62% and 95.0% in visible light range. The refractive index and thickness of single layer thin film were n= 1.29 and ca. 99.0 nm.
Crystalline silicon solar cells with SiNx/SiNx and SiNx/SiOx double layer anti-reflection coatings(ARC) were studied in this paper. Optimizing passivation effect and optical properties of SiNx and SiOx layer deposited by PECVD was performed prior to double layer application. When the refractive index (n) of silicon nitride was varied in range of 1.9∼2.3, silicon wafer deposited with silicon nitride layer of 80 nm thickness and n= 2.2 showed the effective lifetime of 1,370 ㎛. Silicon nitride with n= 1.9 had the smallest extinction coefficient among these conditions. Silicon oxide layer with 110 nm thickness and n= 1.46 showed the extinction coefficient spectrum near to zero in the 300∼1,100 nm region, similar to silicon nitride with n= 1.9. Thus silicon nitride with n= 1.9 and silicon oxide with n= 1.46 would be proper as the upper ARC layer with low extinction coefficient, and silicon nitride with n=2.2 as the lower layer with good passivation effect. As a result, the double layer AR coated silicon wafer showed lower surface reflection and so more light absorption, compared with SiNx single layer. With the completed solar cell with SiNx/SiNx of n= 2.2/1.9 and SiNx/SiOx of n= 2.2/1.46, the electrical characteristics was improved as ΔVoc= 3.7 mV, ΔJsc= 0.11 mA/cm2 and Δ Voc= 5.2 mV, ΔJsc= 0.23 mA/cm2, respectively. It led to the efficiency improvement as 0.1% and 0.23%.
The optical losses associated with the reflectance of incident radiation are among the most important factors limiting the efficiency of a solar cell. Therefore, photovoltaic cells normally require special surface structures or materials, which can reduce reflectance. In this study, nano-scale textured structures with anti-reflection properties were successfully formed on silicon. The surface of sicon wafer was etched by the inductively coupled plasma process using the gaseous mixture of SF6+O2. We demonstrate that the reflection characteristic has significantly reduced by ∼0% compared with the flat surface. As a result, the power efficiency Pmax of the nano-scale textured silicon solar cell were enhanced up to 20%, which can be ascribed primarily to the improved light trapping in the proposed nano-scale texturing.