• Energy Research

Abstract In this work by means studying the crystal structure, optical, electrical, and thermoelectric properties of chip, available and safe for the environment copper iodide CuI, zinc oxide ZnO and indium-doped zinc oxide ZnO:In films we have developed and improved low temperature solution growth Successive Ionic Layer Adsorption and Reaction (SILAR) technique, which allows to deposit these materials over large areas. Output thermoelectric parameters were analyzed for several single p-CuI, n-ZnO and n-ZnO:In thin film thermolegs. The possibility of combining of the obtained p-CuI and n-ZnO:In thin film thermolegs into a thermocouple is shown for the use in new semitransparent planar solar thermoelectric generator working at near-room temperatures through harvesting near-infrared solar light as an energy source to supply electric power to the wireless sensors and microscale devices.

У роботі ми досліджували вплив обробки в плазмі тліючого розряду Н2+ на шари ZnO, які були нанесені на покриті плівками легованого фтором оксиду олова (FTO) скляні підкладки шляхом низькотемпературного осадження з водних розчинів, а саме, методом імпульсного електрохімічного осадження і методом послідовної адсорбції і реакції іонних шарів (SILAR). Показано, що кристалічна структура, морфологія поверхні, хімічний склад і оптичні властивості після плазмової обробки зазнають деяких деструктивних змін через утворення кисневих вакансій Vo і пов'язаних з воднем дефектів, а також внаслідок того, що Н2+-плазма тліючого розряду здатна травити ZnO шляхом відновлення оксиду цинку і випаровування з поверхні Zn. Проте в цілому, наші дослідження продемонстрували досить добру стійкість шарів ZnO до радіаційного та хімічного впливів плазми при одержаній кожним зразком ZnO/FTO високій сумарній густині потоку Н2+ приблизно 8·1018 см – 2. In this work, we investigated the effect of glow-discharge H2+ plasma treatment on ZnO layers deposited on fluorine doped tin oxide (FTO) glass substrates through low temperature aqueous solution growth, namely, via a pulsed electrochemical deposition and by successive ionic layer adsorption and reaction (SILAR) technique. It is shown that the crystal structure, surface morphology, chemical composition and optical properties obtain some destructive changes after plasma processing due to the creation of oxygen vacancies Vo and H-related defects, and additionally, because of the zinc oxide etching by the glowdischarge H2+ plasma through reduction of zinc oxide and evaporation of Zn from the surface. Nevertheless, our investigations show quite good stability of the ZnO layers to the plasma-induced radiation and chemical impacts under high total H2+ fluence received by every ZnO/FTO sample ~ 8·1018 cm – 2.

Abstract Wide bandgap inorganic metal oxide heterojunctions p-NiO/n-ZnO have been prepared by two low temperature solution growth techniques. Namely, one-dimensional ZnO nanostructure arrays electrodeposited in a pulsed mode, and nanocrystalline NiO films synthesized via Successive Ionic Layer Adsorption and Reaction (SILAR). The crystal structure, morphology, and optical properties of NiO films and NiO/ZnO heterostructures were investigated both before and after annealing in air. The analysis of the dark current vs. voltage characteristics and temporal response curves of the NiO films and corresponding NiO/ZnO heterostructures have shown the promise of their use in the effective UV-photodetectors. Poor photovoltaic characteristics of the test samples on the base of obtained NiO/ZnO heterostructures probably associated with their not quite optimal design, and with too large series resistances and diode ideality factors of the manufactured p-NiO/n-ZnO heterojunctions, that will be corrected by scrutinizing the defects in the metal oxides and through the improvement of the NiO/ZnO heterostructure design. Solving these problems will provide the effective application of the wide bandgap metal oxide NiO/ZnO heterostructures prepared by low temperature solution growth in the UV-active semi-transparent solar cells.

Abstract In this work we developed and successfully tested a new design of semi-transparent solar thermoelectric nanogenerator (NG) based on the pulsed electrodeposited array of ZnO nanorods on transparent conducting fluorine doped tin oxide (FTO) substrate. An operation of this NG caused by a distinguishable temperature gradient between 1-D ZnO array and uncoated FTO that spontaneously created under heating of ZnO/FTO composition, including under the influence of sunlight. The developed NG combines benefits of low thermal emittance of FTO and ZnO coatings with TE technology for the harvesting of photo-thermal energy of outdoor sunlight by the windows themselves to produce electricity. The network of such NGs can be integrated harmoniously into buildings without affecting the overall aesthetics and serve as a source of electricity sufficiently high to make sensors entirely autonomous in energy by the harvesting solar near-infrared radiation and heat from ambient.

Abstract In this work, we used solar energy converted via photosynthesis into chemical energy of the biomass of the fast-growing perennial herb Miscanthus × giganteus for the manufacture of nanocellulose (NC) films, which are biodegradable alternative to common petroleum-based polymer substrates used in flexible electronics. To create the NC substrates, we applied an environmentally friendly method of organosolv delignification of plant raw materials carried out at a low temperature and in a relatively short time. Then by means of the low-temperature cheap and scalable method Successive Ionic Layer Adsorption and Reaction (SILAR) we deposited copper iodide (CuI) film of 0.72 µm thickness on both sides of the 12 µm thick NC substrate, and thus obtained light-weight and flexible biodegradable nontoxic thermoelectric material CuI/NC. Crystal structure, morphology, chemical composition, and optical, electrical and thermoelectric properties of the CuI/NC have been researched. Studies have shown that nanostructured p-type semiconductor CuI film in the CuI/NC TE material is quite dense and completely covers the NC surface. It has typical optical direct band gap ≈ 3.0 eV, is single-phase γ-CuI with crystallite sizes in the 19–25 nm range, with moderate dislocation density of (1.6–2.8) × 1015 lines/m2, and tolerable microstrains e of (4–9) × 10−3 a.u. The determined value of the Seebeck coefficient S is ~228 μV K−1, at that, S is constant in the temperature range 290–335 K. Together with the thermoelectric power factor ≈ 36 μW·m−1·K−2it is favorable for the use of CuI/NC as new thermoelectric material for an in-plane design of biodegradable flexible thin film thermoelectric generator (TEG). At temperature gradient of 50 K, the single p-CuI thermoelectric leg made from CuI/NC strip of 3 cm long and 0.5 cm wide generates open circuit voltage 8.4 mV, short circuit current 0.7 µA and maximum output power 1.5 nW. It corresponds to the output power density 10 µW/m2, and thus confirms the suitability of CuI/NC to obtain electricity by the harvesting the waste environmental heat.