The Surface-enhanced Raman spectroscopy is the essential tool for various levels of the molecular studies. In order to become widely used as a fast analytical tool, the enhancing structures such as the nanoparticles have to be simple, inexpensive, and offer good flexibility in enhancing properties and the spectral range. In this paper, we investigated the plasmonic properties of the metal nanoparticles, to which the molecules of interest can be adsorbed, forming the bionanocomplexes. Here, for the first time, we provided the collection of the results gathered in one article, which can serve as the basis or guidance for designing the SERS studies on different bionanocomplexes, various nanoparticle structures, sizes, and excitation wavelengths. The presented plasmonic properties describe the spectral position of the plasmonic resonances as results of their size and structure. The electric field enhancement as a key contributor to the SERS effect is given as well. We considered silver and gold nanoparticles and their variations. Gold is one of the best choice, due to its relevant surface properties, however, suffers from the plasmonic activity and rather static spectral position of the plasmonic resonances. Therefore, one of the main purposes was to show the effective resonance tuning using simple and less expensive geometries. We showed the possibility to adjust the plasmonic resonances with the excitation wavelengths from the blue region to the near infrared region of lasers most commonly used for Raman spectroscopy. The presented studies indicated the high potential of the core-shell structures for this kind of applications.

In recent years, lead halide perovskites have attracted considerable attention from the scientific community due to their exceptional properties and fast-growing enhancement for solar energy harvesting efficiency. One of the fundamental aspects of the architecture of perovskite-based solar cells (PSCs) is the electron transport layer (ETL), which also acts as a barrier for holes. In this work, the influence of compact TiO₂ ETL on the performance of planar heterojunction solar cells based on CH₃NH₃PbI₃ perovskite was investigated. ETLs were deposited on fluorine-doped tin oxide (FTO) substrates from a titanium diisopropoxide bis(acetylacetonate) precursor solution using the spin-coating method with changing precursor concentration and centrifugation speed. It was found that the thickness and continuity of ETLs, investigated between 0 and 124 nm, strongly affect the photovoltaic performance of PSCs, in particular short-circuit current density (J_SC). Optical and topographic properties of the compact TiO₂ layers were investigated as well.

Titanium dioxide layers are the most popular electron transport layer (ETL) in perovskite solar cells. However most studies focuses on mesoporous structure and application with organic–inorganic hybrid perovskite. In this study, the topic of ETL in planar structure of inorganic CsPbBr₃ perovskite solar cells was tackled, the presented approach will reduce production costs and improve cell stability, which is the greatest drawback of perovskite cells especially organic–inorganic perovskite. The potential application of these technology are greenhouses and building integrated PV sector. Here, the two TiO₂ precursors titanium(IV) ethoxide in ethanol and titanium(IV) bis(acetylacetonate) diisopropoxide (Tiacac) were investigated, optimized and compared. TiO₂ layers were deposited on high roughness FTO, without the use of a mesoporous layer, by spin coating method. The correlation between stock solution concentration and thickness of manufactured layers was tracked for both precursors as well as their difference in morphology of the final films and other properties. In particular, conformality and optical properties are better for Tiacac. Slightly lower refractive index of Tiacac-based titania reduced the reflective losses from 7.3 to 6.9% effectively. The obtained layers were used for inorganic solar cells of CsPbBr₃ perovskite to finally settle the issue of optimal thickness and precursor. It is interesting that despite the supremacy in investigated properties of commonly used of the precursor Tiacac, the results of the cells pointed to the Tieth. The efficiency of the champion cell is 6.08% for Tieth, while 5.62% is noted for Tiacac. Trying to figure out this riddle, we shed a new light on the phenomena going on the ETL/inorganic perovskite interface investigating nanoroughness.