Realization of Colored Multicrystalline Silicon Solar Cells with SiO_<b>2</b>/SiN_<i>x</i>:H Double Layer Antireflection Coatings

Abstract

We presented a method to use SiO 2 /SiN x :H double layer antireflection coatings (DARC) on acid textures to fabricate colored multicrystalline silicon (mc-Si) solar cells. Firstly, we modeled the perceived colors and short-circuit current density (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:msub><mml:mrow><mml:mi>J</mml:mi></mml:mrow><mml:mrow><mml:mtext>sc</mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math>) as a function of SiN x :H thickness for single layer SiN x :H, and as a function of SiO 2 thickness for the case of SiO 2 /SiN x :H (DARC) with fixed SiN x :H (refractive index<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>2.1</mml:mn></mml:math>at 633 nm, and thickness = 80 nm). The simulation results show that it is possible to achieve various colors by adjusting the thickness of SiO 2 to avoid significant optical losses. Therefore, we carried out the experiments by using electron beam (e-beam) evaporation to deposit a layer of SiO 2 over the standard SiN x :H for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mn>156</mml:mn><mml:mo>×</mml:mo><mml:mn>156</mml:mn></mml:math> mm 2 mc-Si solar cells which were fabricated by a conventional process. Semisphere reflectivity over 300 nm to 1100 nm and I-V measurements were performed for grey yellow, purple, deep blue, and green cells. The efficiency of colored SiO 2 /SiN x :H DARC cells is comparable to that of standard SiN x :H light blue cells, which shows the potential of colored cells in industrial applications.