• Energy Research

Композитна наносистема Al/Au, синтезована методом співвідновлення з розчину (з використанням таніну та цитрату натрію як відновників), вивчалась методами ЕПР-спектроскопії та спектроскопії електронного поглинання світла в УФ та видимому діапазонах. Виявлену тонку структуру лінії з g = 2.062 (пов’язаної з наночастинками, парамагнітні властивості яких викликані непарною кількістю атомів золота в нанокластері) віднесено до наявності дискретності електронних станів неспареного електрону в об’єднаній електронній оболонці багатоатомної наночастинки. Ця тонка структура проявляється як послідовність резонансних сигналів з близькими значеннями g-факторів. Електронні спектри оптичного поглинання розчину нанокомпозиту Al/Au складались зі смуг поглинання, які слідували еквідистантно з різницею енергій фотонів, що відповідають максимумам сусідніх смуг 0.73-0.74 еВ. Виявлені спектральні особливості пов’язані з квантово-розмірними ефектами в нанокомпозитній системі Al/Au. Оцінки, зроблені на основі експериментальних даних, показують, що розмір кластерів золота, відповідальних за парамагнітні властивості, становить близько декількох нм у діаметрі. The composite Al/Au nanosystems synthesized by co-reduction from solution (with tannin and sodium citrate as reducing agent) are studied by electron paramagnetic resonance (EPR) and UV-vis electron absorption spectroscopies. A fine structure revealed in line with g = 2.062 (associated with particles whose paramagnetism originates from odd number of gold atoms) is attributed to the discrete electronic states of an unpaired electron in a joint electron structure of a polyatomic nanoparticle. This fine structure manifests itself as a sequence of the resonance signals with close values of their g-factors. The UV-vis absorption spectra of the Al/Au nanocomposite solution contain equidistant absorption bands with 0.73-0.7 eV energy differences between the adjacent peaks. These features are attributed to the quantum confinement effects in the Al/Au nanocomposite system. The estimates made on the basis of the experimental data outline the size of the gold containing nanoclusters which in their paramagnetic form are of several nm in diameter.

Abstract Some new structures of thin-film solar converters (SC) based on heterojunctions (HJ) with intermediate semiconductor layers are suggested. Thin protective layers and a quasi-electric field incorporated into the space charge region (SCR) prevent cross-diffusion of HJ components and increase efficiency of charge carrier separation. They also decrease the diode dark current and provide high stability of the converter parameters. Thin (∼ 0.1 μ M) (CdSe) x (ZnTe) 1− x or Zn x Cd 1− x Se layers were used as graded band-gap layers. They were places between a photosensitive II-VI-compound (CdTe, CdSe, CdSe x Te 1− x ) base layer and the transparent Cu 1.8 S layer. The above structures were prepared by vacuum closed space sublimation. The properties of these compounds were studied by electron microscopy and X-ray photoelectron spectroscopy (XPS) with ion etching. The photoelectron properties of structures such as Cu 1.8 S/(CdSe) x )(ZnTe) 1− x /CdSe are presented in detail. The manufacturing technology for the integrated solar batteries based on CdTe, CdSe, and CdSe x Te 1− x compounds was developed. The solar cell parameters under low illumination intensities are comparable to those of solar batteries based on c-Si and a-Si. The competitiveness of the polycrystalline thin-film SC is due to ease and low cost of fabrication (as compared with c-Si and a-Si) and also to the extended photosensitivity range (as compared to a-Si).

Abstract Hybrid photovoltaic (PV) cells based on cadmium sulphide (CdS) single crystal and phthalocyanine (Pc) films have been developed and their PV performance was measured. Five different Pcs have been selected as candidates for the PV cell, PcCu, PcMn, PcZn, PcMg, and PcVO. It was found that all the chosen Pcs are capable of forming a hybrid heterojunction with the CdS surface, and that illumination results in charge separation at the interface. However, the performance of the In/CdS/Pc/Au device was dependent on the Pc used. PV cells with PcMg and PcZn showed the best results. An unoptimized cell with the PcZn film showed an open-circuit voltage V oc =0.595 V, a short-circuit current density J sc =1.88 μA/cm 2 , a fill factor FF=0.265, and a power conversion efficiency PCE=3.0×10 −4 % under the AM1.5 conditions.