The effect of SnO₂ addition (0, 1, 2, 4 wt.%) on thermoelectric properties of c-axis oriented Al-doped ZnO thin films (AZO) fabricated by pulsed laser deposition on silica and Al₂O₃ substrates was investigated. The best thermoelectric performance was obtained on the AZO + 2% SnO₂ thin film grown on silica, with a power factor (PF) of 211.8 μW/m·K² at 573 K and a room-temperature (300 K) thermal conductivity of 8.56 W/m·K. PF was of the same order of magnitude as the value reported for typical AZO bulk material at the same measurement conditions (340 μW/m·K²) while thermal conductivity κ was reduced about four times.

Transparent luminescent solar concentrator (LSC) windows with edge-attached photovoltaic (PV) cells have the potential for improving building efficiency without compromising aesthetics and comfort. Optimization of such windows requires an inexpensive simulator for experimenting with various designs. We report, for the first time to the best of our knowledge, the simulator of a transparent LSC window in the form of a plastic container filled with a colloid of photoluminescent nanoparticles (NPs) in an organic solvent (1-propanol). The exemplary NPs were produced by ball milling of the powder of rare earth (RE)-doped phosphor NaYF ₄ :Yb ³⁺ ,Er ³⁺ synthesized by the wet method. The NPs converted the ultraviolet (UV) solar spectrum into visible/near infrared (NIR) via spectral down-shifting and down-conversion (quantum cutting). With a photoluminescence quantum yield (PLQY) of the phosphor <0.4%, the LSC at a nanocolloid concentration of ∼0.1 g solids per 100 mL liquids demonstrated a power conversion efficiency of 0.34% and a power concentration ratio of ∼0.022 comparable to the LSCs with RE-doped NPs with 200 times greater PLQY. At the same time, the 3 cm thick LSC window simulator had ∼90% transmittance to the sunlight. The content and concentration of the nanocolloid could be easily modified to optimize the LSC window performance without a costly window making process.

The chapter describes the application of Q-switched lasers to the concurrent multi-beam multi-target pulsed laser deposition (CMBMT-PLD) of the high-entropy alloy (HEA) films. A six-beam system for such a process additionally included permanent magnets under the PLD targets and the substrate and a substrate heater. The magnets narrowed down the plasma plumes from the targets and increased the material deposition rate. Three- (Au-Ag-Cu), four- (previous three + Al), five- (previous four + Ti), and six-metal (previous five + W) films were deposited on Cu, Al, Fe, and Ni substrates. Scanning electron microscopy and X-ray analysis indicated that the films were the aggregates of crystalline nanoparticles (NPs) of mostly individual metals and double-metal alloys. Heating the substrates to up to 300°C resulted in the formation of a wider variety of double-alloy nanoparticles due to higher mobility and reactivity of the deposited atomic species. The HEA films amplified the photoluminescence (PL) of the perovskite CsPbBr₃ quantum dots (QDs) deposited on the top by 6 to 16 times. This was because of two simultaneous effects. The first was the enhancement of the incident ultraviolet radiation (372-nm wavelength laser) by the localized surface plasmon polariton resonance in the metal NPs surrounding the perovskite QD. The second was the fast decay of the excited state of the QD due to a resonant coupling between the QD and the NPs in its vicinity. The findings described in this chapter might be useful for the applications in optical sensing.

Polymer nanocomposite coatings of solar photovoltaic cells that absorb solar ultraviolet (UV) radiation and convert it into visible and near-infrared (NIR) light can increase the operational lifetime and the energy efficiency of the cells. We report a polymer nanocomposite spectrum converting layer (SCL) made of colorless polyimide CORIN impregnated with the nanoparticles (NPs) of fluoride NaYF ₄ doped with three-valent ions of Europium at a molar concentration of 60%. The NPs were the nanocrystals (179 ± 35 nm in size) in thermally stable hexagonal beta-phase. The visible-NIR photoluminescence quantum yield of the nano-powder was ∼69%. The SCLs were applied using the open-air multi-beam multi-target pulsed laser deposition method to silicon heterojunction (SHJ), copper-indium-gallium-selenide (CIGS), and inverted metamorphic multijunction (IMM) solar cells. The cells were exposed to UV radiation from a 365 nm light emitting diode. The I – V characteristics of the cells were measured with a solar simulator using AM0 filter. The proposed SCLs improved the UV stability of all three types of the cells: the power degradation of SHJs and IMMs cells was stopped or slightly reversed and the degradation rate of CIGSs decreased by ∼25%. The proposed SCLs have great commercial potential, especially for applications to space power.