Preparation and Characterization of High‐Reflectivity Photovoltaic Coatings Based on Bi–B–Si Glass‐Ceramics

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Chinese explanation / 中文解读

中文解读待补充：本站会优先为光伏效率、钙钛矿太阳能电池、储能技术、太阳能热利用、BIPV、并网技术等高价值论文补充中文说明。

Original abstract

ABSTRACT As a high‐performance functional layer integrated onto the glass back sheet, the high‐reflectivity photovoltaic (PV) coating demonstrates significant potential to enhance module power output. This enhancement arises from the retroreflection of unabsorbed solar irradiance toward the active cell region, thereby enabling secondary optical absorption. Consequently, optimizing the reflectivity of these coatings emerges as a crucial factor in advancing module performance. Although previous studies indicate that in situ crystallization during sintering can augment reflectivity, this method frequently encounters challenges such as uncontrolled nucleation kinetics, heterogeneous crystal distribution, and considerable batch‐to‐batch variability. To overcome these constraints, we present the development of an advanced high‐reflectivity PV ink based on a ternary Bi 2 O 3 –B 2 O 3 –SiO 2 (Bi–B–Si) glass‐ceramic system. The precipitation of Bi 4 (SiO 4 ) 3 crystalline phases within the glass matrix imparts favorable thermo‐optical characteristics, attributed to their high refractive index ( n = 2.02–2.06) and coefficient of thermal expansion (CTE = 70 × 10 −7 /°C). By systematically adjusting the Bi/Si molar ratio to values between 0.23 and 0.60, the content of Bi 4 (SiO 4 ) 3 crystals was controlled, resulting in crystallinity values ranging from 78% to 90% of samples W1–W4. Experimental results reveal a positive correlation between crystallinity and coating performance, with the highest reflectance of 90.25%. The reflectance enhancement is attributed to two complementary mechanisms. First, the increase in Bi 4 (SiO 4 ) 3 content is accompanied by a decrease in image‐derived surface porosity, suggesting that crystalline‐phase evolution and glass‐flow behavior may contribute to coating densification and reduced transmission loss. Second, the refractive‐index discontinuities at the Bi 4 (SiO 4 ) 3 /glass and TiO 2 /glass interfaces promote interfacial reflection and diffuse scattering. The substantial refractive index mismatch (Δ n ) between the submicron crystallites and the glass matrix ( n = 1.52) facilitates higher Fresnel reflection, effectively reducing photon penetration depth and maximizing macroscopic reflectance.

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