A black aluminum (B-Al) film was deposited onto the surface of a stack structure of platinum/Pb(ZrxTi1 − x)O3/platinum (Pt/PZT/Pt) to convert light into a heat variation and the heat variation into a polarization change. A comparison was performed between B-Al/Pt/PZT/Pt and conventional Pt/PZT/Pt structures. An absorbance higher than 95% was measured for the B-Al layer over a large range of wavelengths varying from 350 nm to 1000 nm. The theoretical model shows that heat diffusion was extremely fast through the layers, and the sample holder played a key role in the variation and stabilization of the system temperature. A doubled variation of the polarization was observed when the light was applied onto the surface of the stack structure with stable B-Al on the top. This behavior was interpreted by the larger temperature variations induced under the highly absorptive B-Al layers, in good correlation with the theoretical model prediction based on the heat fluxes in the structures. This result is very promising for possible pyroelectric energy harvesting applications.
Luminescent materials enable warm white LEDs, molecular tagging, enhanced optoelectronics and can improve energy harvesting. With the recent development of multi-step processes like down- and upconversion and the difficulty in sensitizing these, it is clear that optimizing all properties simultaneously is not possible within a single material class. In this work, we have utilized the layer-by-layer approach of atomic layer deposition to combine broad absorption from an aromatic molecule with the high emission yields of crystalline multi-layer lanthanide fluorides in a single-step nanocomposite process. This approach results in complete energy transfer from the organic molecule while providing inorganic fluoride-like lanthanide luminescence. Sm3+ is easily quenched by organic sensitizers, but in our case we obtain strong fluoride-like Sm3+ emission sensitized by strong UV absorption of terephthalic acid. This design allows combinations of otherwise incompatible species, both with respect to normally incompatible synthesis requirements and in controlling energy transfer and quenching routes.
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