Effect Of Annealing On Structure, Morphology, Electrical And Optical Properties Of Nanocrystalline TiO2 Thin Films

Semi-transparent and highly conducting nanostructured titanium oxide thin films have been prepared by sol-gel method. Thin films of TiO2 deposited on glass substrates using spin coating technique and the effect of annealing temperature (400 - 700 °C) on structural, microstructural, electrical and optical properties were studied. The X-ray diffraction and Atomic force microscopy measurements confirmed that the films grown by this technique have good crystalline tetragonal mixed anatase and rutile phase structure and homogeneous surface. The study also reveals that the rms value of thin film roughness increases from 7 to 19 nm. HRTEM image of TiO2 thin film (annealed at 700 °C) shows that a grain of about 50 - 60 nm in size is really aggregate of many small crystallites of around 10 - 15 nm. Electron diffraction pattern shows that the TiO2 films exhibited tetragonal structure. The surface morphology (SEM) of the TiO2 film showed that the nanoparticles are fine with an average grain size of about 50 - 60 nm. The optical band gap slightly decreases from 3.26 - 3.24 eV and the dc electrical conductivity was found in the range of 10-6 to 10-5(Ω·cm)-1 when the annealing temperature is changed from 400 to 700 °C. It is observed that TiO2 thin film annealed at 700 °C after deposition provide a smooth and flat texture suited for optoelectronic applications. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/967

Combining electron-accepting phthalocyanines and nanorod-like CuO electrodes for p-type dye-sensitized solar cells

This is the peer reviewed version of the following article: Angewandte Chemie - International Edition 54.26 (2015): 7688-7692, which has been published in final form at http://dx.doi.org/10.1002/anie.201501550]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingA route is reported for the synthesis of two electron-accepting phthalocyanines featuring linkers with different lengths as sensitizers for p-type dye-sensitized solar cells (DSSCs). Importantly, our devices based on novel nanorod-like CuO photocathodes showed high efficiencies of up to 0.191%: the highest value reported to date for CuO-based DSSCs. The longer the better: Novel electron-accepting zinc phthalocyanines with different linker lengths performed well in combination with nanorod-like CuO electrodes in p-type dye-sensitized solar cells. A particularly high efficiency of 0.191% was observed with a photosensitizer containing a carboxyethynyl anchor (see picture; R is a branched alkyl group)The authors thank the German Science Council (DFG) for the financial support in the framework of the Cluster of Engineering of Advanced Materials (EAM), the MINECO Spain (CTQ2014- 52869/BQU), the Comunidad de Madrid Spain (FOTOCARBON, S2013/MIT-2841), and the European Union within the FP7-ENERGY-2012-1 nr. 309194-2, GLOBALSO