3D-Printed PlasticWindows for PhotoelectrochemicalApplications

The integration of additive manufacturing with photoelectrochemical (PEC) systems represents a promising avenue for cost-effective and customizable reactor designs. However, the use of 3D-printed plastic components as optical windows remains underexplored, particularly concerning their transparency, material suitability, and printing parameter optimization. Addressing this gap is crucial to enable fully 3D-printed reactors and windows for applications such as water splitting and light-driven chemical conversions. This work aims to evaluate the feasibility of 3D-printed plastic windows for PEC applications by systematically investigating the impact of printing parameterssuch as infill patterns, fill percentage, and layer thicknesson the optical and mechanical properties of three widely used polymers: PLA, PETG, and ABS. A detailed transmittance mapping approach was developed to guide the selection of suitable configurations based on application-specific needs. We fabricated 243 plastic samples and characterized their transmittance in the UV–visible range, correlating the results with printing configurations. PLA emerged as the most transparent material, achieving up to 76.8% transmittance in the visible spectrum. PETG achieved 52% transparency. ABS, on the other hand, was found to be unsuitable due to its opacity, exhibiting <5% transmittance. Proof-of-concept experiments using these plastics as optical windows for PEC water oxidation TiO₂ and BiVO₄ demonstrated that PLA and PETG enabled satisfactory operation, achieving up to 78% and 52% of the performance of standard quartz windows, respectively. Our findings highlight the potential of 3D-printed plastic windows as viable, low-cost alternatives to traditional quartz components, with the added advantage of customization for specific optical and structural requirements. This study paves the way for scalable, sustainable, and tailored PEC reactor designs, opening opportunities in renewable energy and environmental applications.