Design of multi-layer anti-reflection coating for terrestrial solar panel glass

Abstract

To date, there is no ideal anti-reflection (AR) coating available on solar glass which can effectively transmit the incident light within the visible wavelength range. However, there is a need to develop multifunctional coating with superior anti-reflection properties and self-cleaning ability meant to be used for solar glass panels. In spite of self-cleaning ability of materials like TiO 2 and ZnO, these coatings on glass substrate have tendency to reduce light transmission due to their high refractive indices than glass. Thus, to infuse the anti-reflective property, a low refractive index, SiO 2 layer needs to be used in conjunction with TiO 2 and ZnO layers. In such case, the optimization of individual layer thickness is crucial to achieve maximum transmittance of the visible light. In the present study, we propose an omni-directional anti-reflection coating design for the visible spectral wavelength range of 400-700 nm, where the maximum intensity of light is converted into electrical energy. Herein, we employ the quarter wavelength criteria using SiO 2 , TiO 2 and ZnO to design the coating composed of single, double and triple layers. The thickness of individual layers was optimized for maximum light transmittance using essential Mcleod simulation software to produce destructive interference between reflected waves and constructive interference between transmitted waves.

Optimization of multilayer anti-reflection coatings for efficient light management of PEDOT:PSS/c-Si heterojunction solar cells

“…The optical interference matrix, commonly known as transfer matrix, method has been employed to design multilayer anti-reflection coatings on the substrate material having refractive index, n s [22,[27][28][29]. The idea behind this method is to adjust the electric and magnetic field of the incident light on the surface of multilayer optical coatings [29].…”

“…This condition is fulfilled when the optical thickness of the ARC layer (d ARC ) is equal to a quarter of the wavelength (λ) at which reflectance is zero. This condition can be expressed mathematically by equation [22] d 4n m 2n m 0, 1, 2, 3 10…”

“…Although, PEDOT:PSS having refractive index (RI) of ∼1.6 reduces the reflectance of the silicon to about 20%, it is still high for reducing the optical loss in the PEDOT:PSS/c-Si heterojunction solar cell [10,21]. This is happened due to the reason that PEDOT:PSS as a single ARC layer can reduce reflection at a specific wavelength at normal incidence and unable to provide broadband reduction in reflectance over a wide range of incidence angles [22,23].…”

Long-Term Reliability Evaluation of Silica-Based Coating with Antireflection Effect for Photovoltaic Modules

“…Both must be considered in the developing of high-efficiency PV systems. The cover glass of PV modules reflects approximately 4% of the incident light irradiated to it [7]. Energy losses of the incident light on PV modules occur through the reflection of the air/glass interface due to the difference in the refractive index of the medium [8].…”

Preparation of single- and double-layer antireflective coatings by sol-gel method

“…Therefore, AR films applied on a glass surface must have a refractive index (RI) value of 1.21-1.25 to reach zero-reflectivity in air medium (n01.0) [9]. The common materials used as AR coating in the visible range are SiO2 (nc=1.45), Al2O3 (nc=1.65), MgF2 (nc=1.38), SiO (nc=1.85) and ZnO (nc=2.0) [9,10], but, none of these materials has such a low RI value. Among these materials, SiO2 is generally preferred due to its relatively low RI value [11].…”