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We present the design and synthesis of a novel optically transparent platform based on the combination of NaYF4: Er3+, Yb3+ upconverting nanoparticles (UCNPs) and mesoporous metal oxide thin films (MOTFs). The UCNP were obtained by the thermolysis method and were deposited onto a glass substrate by spin coating. The MOTFs (TiO2, ZrO2 and SiO2), prepared by the combination of the sol‐gel approach and the self‐assembly of surfactants, were subsequently deposited on top of the particles giving rise to an ultrathin composite. The characterization of the obtained composite films indicates that they blend the properties of both starting materials: they exhibit upconverting properties, as they are capable of emitting visible light when irradiated in the NIR region, and the MOTFs deposited on top provide an ordered array of mesopores with highly accessible porosity. As the UCNPs emission properties depend on their surrounding temperature, the composite films were tested for temperature sensing applications, using both emission intensity and lifetimes of different signals, with promising results. [ABSTRACT FROM AUTHOR]

In this work, Tamm mode based devices were synthesized using mesoporous thin films as building blocks. Several systems were designed and built, based on silicon and titanium mesoporous oxides obtained through amphiphilic molecules templating approach. The devices were evaluated for organic vapor detection and the obtained results demonstrate that the developed Tamm devices can be used for such purpose. Distributed Bragg reflectors (DBRs) were also synthesized and evaluated as a comparison. In both cases, the detection of organic vapors is possible thanks to capillary condensation inside the well‐ordered and accessible porosity that give rise to equivalent results to the ones obtained for the detection of liquids. Both kinds of devices behave in a similar way, but the figure of merit for the Tamm mode based ones is between two and three times larger due to the smaller width of the sensitive band. Moreover, it was demonstrated that the response time of the sensor is less than 80 s in all tested cases. In addition, such parameter clearly depends on both the physicochemical characteristics of the solvents (in particular, boiling temperature and vapor pressure) and the characteristics of the sensor itself. The results presented in this work represent a proof of concept towards the production of robust and reusable detection devices based on the combination of functional mesoporous thin films and the Tamm mode. [ABSTRACT FROM AUTHOR]