Development of flexible nanocellulose-based composites with enhanced hydrophobicity and improved haze for efficient light management in solar cells

Abstract

The proliferation of flexible electronic products derived from petroleum substrates in the market has exacerbated environmental pollution stemming from electronic waste generation. As a result, there is an increasing demand for cellulose nanofiber substrates that are green and degradable. However, substantial challenges remain in addressing the hydrophilicity of nanocellulose substrates and optimizing their optical properties for commercial viability. In this study, we propose a multifunctional composite film material through the use of amidation modification and biomineralization technology. We successfully grafted highly carboxylated transparent oxide nanocellulose (TCNF) and octadecylamine (ODA) using carefully designed amidation conditions. Through the carboxyl group after amination, we were able to generate amorphous calcium carbonate (ACC) in situ, resulting in the creation of a flexible, sustainable, and transparent TCNF/ODA/CaCO3 composite film with high hydrophobicity and haze. This was confirmed by a water contact angle value of 138.21° and a haze value of 84.8%. The composite film exhibits low surface energy and high dual-scale surface roughness, while its internal structure is relatively porous and loose, but still possesses multi-scale interface interactions. We demonstrate a strong correlation between the multifunctional properties and structural properties of the composite films in this work, thereby achieving effective light management applications in solar cells. Our findings are expected to provide new insights and ideas for the design of multifunctional green flexible solar cell device substrate materials.