In situ investigation of gold nanoclusters growth in polymer matrices

Polytetrafluoroethylene (PTFE) and polyparaphenylene sulphide (PPS) films were filled with gold (Au) nano-clusters by co-deposition in a vacuum. Multi-component film, filled simultaneously with Au and dye was deposited for the first time. Film formation was studied using optical absorptionПлівки політетрафторетилену та поліпарафеніленсульфіду було наповнено нанокластерами золота та барвника методом сумісного випаровування в вакуумі. Формування плівок було досліджено, застосовуючи оптичну спектроскопію. Було знайдено значні перетворення оптичних спектрів у процесі росту плівок, які пов’язані з ростом кластерів золота та їх агрегатів. Обробка пари плазмою у процесі нанесення плівок призвела до формування менших, але більш агрегованих кластерів золота. В трикомпонентних плівках нанокластери золота виявили сферичну форму.Пленки политетрафторетилена и полипарафениленсульфида были наполнены нанокластерами золота и красителя методом совместного испарения в вакууме. Формирование пленок было исследовано, используя оптическую спектроскопию. Были найдены значительные преобразования оптических спектров в процессе роста пленок, связанные с ростом кластеров золота и их агрегатов. Обработка пара плазмой в процессе нанесения пленок привела к формированию меньших, но более агрегированных кластеров золота. В трехкомпонентных пленках нанокластеры золота проявили сферическую форму

Injection Spectroscopy of Deep Traps in Nanostructured Films of Cadmium Sulfide

Nanocrystallin CdS films with controlled stoichiometry deposited by CSVS were investigated by meth-od of the current-voltage characteristics in ITO/CdS /In structures. It was shown that in the case of cadmi-um excess (S Cd) charge flow mechanism is deter-mined by monomolecular recombination. In the band gap of CdS with excess of cadmium there was detect-ed localized states with energy Et = 0.514 ± 0.026 eV, while in the material with Excess sulfur there are two localized states with energy Et1 = 0.514 ± 0.026 eV and Et2 = 0.700 ± 0.026 eV. Full concentration of lo-calized states is more than 2·1021 m-3 – 5·1022 m-3. Dependence of injection in parameters and nature of in-jection in the structures based on nanostructured CdS films on their stoichiometry was determined When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3524

Injection Spectroscopy of Deep Traps in Nanostructured Films of Cadmium Sulfide

Nanocrystallin CdS films with controlled stoichiometry deposited by CSVS were investigated by meth- od of the current-voltage characteristics in ITO/CdS /In structures. It was shown that in the case of cadmi- um excess (S <Cd) charge flow mechanism both in the dark and under illumination is determined by bimo- lecular recombination in the material. In the case of excess sulfur (S>Cd) charge flow mechanism is deter- mined by monomolecular recombination. In the band gap of CdS with excess of cadmium there was detected localized states with energy Et = 0.514 ± 0.026 eV, while in the material with Excess sulfur there are two localized states with energy Et1 = 0.514 ± 0.026 eV and Et2 = 0.700 ± 0.026 eV. Full concentration of localized states is more than 2·1021 m-3 – 5·1022 m-3. Dependence of injection in parameters and nature of injection in the structures based on nanostructured CdS films on their stoichiometry was determined. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3390

Macroscopic versus microscopic photovoltaic response of heterojunctions based on mechanochemically prepared nanopowders of kesterite and n-type semiconductors

Mechanochemically prepared nanopowder of selenium-free kesterite Cu2ZnSnS4 (CZTS) in combination with n-type semiconductors, i.e., CdS, ZnO and TiO2, was tested in planar and bulk-heterojunction solar cells. The samples have been studied by macroscopic current-voltage (I-V) measurements and Kelvin-probe atomic-force microscopy (KPFM). KPFM images taken under light illumination showed the distribution of the potential across the surface, with negative potential on the n-type semiconductor domains and positive potential on the CZTS domains, which indicated charge separation at the interface of the counterparts. The best result was found for the CdS-CZTS composition, which showed a potential difference between the domains up to 250 mV. These results were compared with the planar heterojunctions of CdS/CZTS and TiO2/CZTS, where CZTS nanopowder was pressed/deposited directly onto the surface of films of the corresponding n-type semiconductors. Again, I-V characteristics showed that cells based on CdS/CZTS heterojunctions have the best performance, with a photovoltage up to 200 mV and photocurrent densities up to 0.1 mA/cm2. However, the carrier generation was found to occur mainly in the CdS semiconductor, while CZTS showed no photo-response and served as the hole-transporting layer only. It is concluded that sensitization of the kesterite powder obtained by mechanochemical method is necessary to improve the performance of the corresponding solar cells