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arXiv · 2510.03710

Hierarchically Engineered Titanium Suboxide Films for High-Efficiency Solar Thermal Conversion

Silpa S·Ann Eliza Joseph·Srinivas G·Harish C Barshilia·Vinayak B Kamble
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Abstract

We report the development of broadband solar absorber coatings based on titanium suboxide composite thin films on aluminium substrates. The films are fabricated via scalable DC magnetron sputtering using a Ti target, followed by post-annealing in a fixed $O_2$ partial pressure of 0.45 mbar. By tuning deposition time and annealing temperature, a composite phase of $Ti_2O_3$ and $TiO_2$ was achieved. The Raman mapping of the films substantiates the distribution and coexistence of the two phases. The optimized sample, deposited for 10 min and annealed at 500 $^oC$, exhibited a superior solar absorptance (${\alpha}_s$ = 0.913) and optimally low thermal emittance (${\epsilon}_t$ = 0.11). Nevertheless, the 15- and 20-min deposited films also showed a promising absorptance (>0.85) and emittance values (<0.13). Morphological studies revealed island-type nanostructures, leading to enhanced photothermal performance via electric field confinement, which is validated by optical simulations. This work provides a promising route toward efficient, scalable, and cost-effective spectrally selective solar absorbers for solar thermal applications.

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Silpa S, Ann Eliza Joseph, Srinivas G, Harish C Barshilia, Vinayak B Kamble. 2025-10-04. Hierarchically Engineered Titanium Suboxide Films for High-Efficiency Solar Thermal Conversion. https://arxiv.org/abs/2510.03710

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