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Polypyrrole (PPy) have been extensively studied because of their low cost, easy production, good conductivity and controlled doping/de-doping properties as well as extensive applications in various areas such as energy storage, sensors, and electronic devices 1, 2. A detailed study of the effects of different electropolymerization conditions on the supercapacitive properties of polypyrrole (ppy) films doped using different dopants deposited on stainless steel was reported. The resulting thin films have been characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The electrochemical properties of PPy thin films were investigated by cyclic voltammetry, electorochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge. The results showed that the different electrodeposition operating conditions of synthesis and the type of dopant and the electrolyte used significantly affect the supercapacitive properties of PPy thin films. Thus, these results provide a useful orientation for the use of optimized electrodeposition modes for the growth of PPy thin films to be applied as electrode material in supercapacitors and achieved a specific capacitance of 266 F/g for amperometric deposited PPy thin film doped with 0.03 M dodecylbenzene sulfonic acid (DBSA) and using 0.1 M H2SO4 as an electrolyte. References Cai, Z.; Xiong, H.; Zhu, Z.; Huang, H.; Li, L.; Huang, Y.; Yu, X., Electrochemical synthesis of graphene/polypyrrole nanotube composites for multifunctional applications. 2017, Synthetic Metals 227, 100-105. Dubal, D. P.; Lee, S. H.; Kim, J. G.; Kim, W. B.; Lokhande, C. D., Porous polypyrrole clusters prepared by electropolymerization for a high performance supercapacitor. 2012, Journal of Materials Chemistry 22, 3044-3052. Figure 1: Cyclic voltammetry of PPy doped by DBSA and a schematic diagram of supercapacitor components Figure 1

Organometallic trihalide perovskite solar cells have attracted the researchers due to their easy fabrication, low cost and high power conversion efficiencies. Hole-conductor free perovskite solar cell is the most interesting structure to be commercialized due to its manufacturing simplicity, lower cost materials and higher stability compared to the other structures such as p-i-n and n-i-p structures [1-2]. The main issues of this type of solar cells are the poor fill factor and low power conversion efficiency due to the direct contact between TiO2 and carbon, absence of hole transport layer and poor interfacing between TiO2/perovskite interface. To overcome this problem, the influence ZrO2 and spiro-OMeTAD and correlate them with the photovoltaic performance will be presented. Three different cells have been prepared and compared to each other, typically named “cell 1” without ZrO2 spacer layer, “cell 2” with ZrO2 spacer layer between mesoprous TiO2/carbon electrode interface and “cell3” with perovskite doped spiro-OMeTAD with 50 wt%. Different photovoltaic performances were observed and enhancement of the fill factor has been achieved. The strength of our perovskite CH3NH3PbI3 layer has been enhanced with a ratio of 10 wt% of PbCl2, the HTM-free PSCs based on the incorporation ZrO2 “cell 2” has a significant increase in the fill factor more than 0.49, and “cell 1” achieved a higher efficiency of 5.4 %. References Chenxi Zhang . Yudan Luo . Xiaohong Chen . Yiwei Chen . Zhuo Sun . Sumei Huang. Effective Improvement of the Photovoltaic Performance of Carbon-Based Perovskite Solar Cells by Additional Solvents, 2016, Nano-Micro Lett. 8(4):347–357. Using a low-temperature carbon electrode for preparing hole-conductor-free perovskite heterojunction solar cells under high relative humidity. 2016, Nanoscale, 8, 7017 Figure 1: Schematic representation of the cell structure. Figure 1

Graphene Quantum Dots (GQDs) show promise for many technological applications because GQDs have low toxicity and are chemically inert, biocompatible, and resistant to photobleaching [1]. We report a simple route to prepare graphene quantum dots (GQDs) using glucose carbonization. GQDs functionalized with phenylboronic acid receptors were employed as a sensing material for a nonenzymatic glucose sensor. GQDs display high surface area and the carboxylic moieties at their edges provide them with water dispersibility and proper functional groups to be complexed with several compounds [2]. Therefore, GQDs considered as a good sensing probe. The prepared GQDs were characterized using different techniques such as UV-visible and photoluminance spectroscopies, X-ray diffraction, transmission electron microscopy (TEM) and Raman spectroscopy. TEM micrographs confirmed the preparation of 8-10 nm GQDs. The emission peak of the GQDs appears at 450 nm. The developed sensor has linear response to glucose over a concentration range of 5 -50 mM. References: 1) Shen, J.; Zhu, Y.; Yang, X.; Li, C. Graphene Quantum Dots: Emergent Nanolights for Bioimaging, Sensors, Catalysis and Photovoltaic Devices. Chem. Commun. 2012, 48, 3686. 2) Liu, J.-J.; Zhang, X.-L.; Cong, Z.-X.; Chen, Z.-T.; Yang, H.-H.; Chen, G.-N. Glutathione Functionalized Graphene Quantum Dots as Selective Fluorescent Probes for Phosphate-Containing Metabolites. Nanoscale 2013, 5, 1810−1815

Quantum dots (QDs) have been applied in many research fields such as chemistry, biology and medicine because of their unique physical-chemical properties such as broad absorption spectra, narrow symmetric emission bands and high photo-stability [1]. QDs showed great promises for detection of organic and inorganic analysts. For example, CuInS2 as QDs have been used for detection of ascorbic acid and folic acid [2]. In this study, a sensitive and simple method based on the fluorescence quenching of CuInS2 quantum dots (QDs) were used for the determination of nickel ions (Ni(II) ions) in drinking water samples. Water-soluble and biocompatible 3-mercaptopropionic acid-capped CuInS2 QDs was synthesized by one step aqueous route. The fluorescence intensity of synthesized QDs significantly decreased in the presence of Ni(II) ions. The emission intensity of CuInS2 QDs has an inversely proportional with the concentration of Ni(II) a linear fit with negative slope. The detection range was for Ni2+ concentration in the range of 133 to 2133 ppm. The method showed good sensitivity and was satisfactorily applied to the determination of Ni2+ contamination in real water samples, obtained from tap water. References: [1] Liang JG, Huang S, Zeng DY, He Z, Ji X, Ai X, et al. CdSe quantum dots as luminescent probes for spironolactone determination. Talanta 2006; 69:126–30. [2]Liu SY, Hua JJ, Su XG. Detection of ascorbic acid and folic acid based on water-soluble CuInS2 quantum dots. Analyst 2012; 137:4598–604.

Nanomaterials are becoming one of the most important classes of material research [1]. For example, quantum dots (QDs), especially water soluble QDs, have been used in many areas of research [2-3]. QDs are nanosize crystals of inorganic semiconductors with diameter in the range of 1-10 nm [4]. At such small sizes (close to or smaller than the dimensions of the exciton Bohr radius within the corresponding bulk material), these nanostructured materials behave differently from bulk solids, because of quantum-confinement effects [4]. As a result of quantum-confinement, they have unique optical and electronic properties such as broad excitation spectra and narrow, symmetric and tunable emission spectra [4]. Therefore, QDs have been used as novel luminescent sensors for chemical and biological species [5-8]. This study fabricated cadmium telluride (CdTe) QDs from aqueous solution containing CdCl2 and Te precursor in presence of thioglycolic acid. The resulted QDs were characterized by using Uv-Vis. spectroscopy, photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). The results demonstrated that low concentration, in nano-molar range, of Hg(II) ions could effectively quench the CdTe QDs fluorescence because Hg(II) ions form a stable complex with QDs coating (thioglycolic acid) which allow for an effective electron transfer from the QDs to the Hg(II). A linear response to Hg(II) ions in the concentration range from 0.625 to 8.0 n M was observed and the detection limit of this sensor was 0.625 nM and sensitivity was equal to 53.4 /nM. References Rosi NL, Mirkin CA Nanostructures in biodiagnostics. Chem Rev 105:1547–1562 (2005) Goldman ER, Balighian ED, Mattoussi H, Kuno MK, Mauro JM, Tran PT, Anderson GP (2002) Avidin: a natural bridge for quantum dot-antibody conjugates. J Am Chem Soc 124:6378–6382 Chen Y, Rosenzweig Z (2002) Luminescent CdS quantum dots as selective ion probes. Anal Chem 74:5132–5138 Alivisatos AP (1996) Perspectives on the physical chemistry of semiconductor nanocrystals. J Phys Chem 100:13226–13239 Chan WCW, Maxwel DJ, Gao X, Bailey RE, Han M, Nie S (2002) Luminescent quantum dots for multiplexed biological detection and imaging. Curr Opin Biotechnol 13:40–46 Zhang L, Ci Xu, Li B (2009) Simple and sensitive detection method for chromium(VI) in water using glutathione—capped CdTe quantum dots as fluorescent probes. Microchim Acta 166: 61–68 Landes C, Burda C, Braun M, El-Sayed MA (2001) Photoluminescence of CdSe nanoparticles in the presence of a hole acceptor: n-Butylamine. J Phys Chem B 105:2981–2986 Dong F, Hu K, Han H, Liang J (2009) A novel method for methimazole determination using CdSe quantum dots as fluorescence probes. Microchim Acta 165:195–201

In the operational process of dye sensitized solar cell (DSSC) photo excitation of the sensitizer is followed by electron injection into the conduction band of the mesoporous oxide semiconductor. The dye molecule is regenerated by the redox system, which itself is restored at the counter electrode by electrons passed through the load. Some electrons in conduction band of the photo-electrode travel back to the electrolyte, which results in a loss of efficiency in the DSSC [1-2]. Therefore, it is important to suppress this recombination reaction and to improve the collection of photo-injected electrons for enhancing the cell performance [3]. Tungsten oxide (WO3) is a semiconductor oxide material with a band-gap of 2.6–3.0 eV [3], and it is becoming the focus of research attention due to its unique electronic properties. Various WO3 nanostructures (nanoparticles, nanoplatelets, nanorods, and nanowires) are of special interest as promising candidate [3, 4] as a photo-electrode. It is well known that polyaniline (PANI) is one of the most promising conducting polymers. Due to its high electrochemical activity, environmental stability and low cost, PANI materials have been employed to fabricate efficient counter electrode in DSSCs [5]. Recently, there is a large interest to incorporate carbon nanotubes (CNTs) into organic solar cells because of the unique electrical properties of CNTs. For example, CNTs were used as electron acceptors in the photoactive layer of the solar cells [6]. Also, CNTs were used as transparent anodes in order to replace the prevailed wildly used indium tin oxide (ITO) [7]. In this work nanomaterials for photo- and counter-electrodes are synthesized and investigated. The morphological structures of WO3 nanorods deposited onto TiO2 nanoparticles and PANI-CNTs. The electro-catalytic activity of the counter electrode is investigated using cyclic voltammetry technique. The CNTs blended PANI base counter electrode and ruthenium dye sensitized WO3/TiO2 based photo-electrode were assembled to form DSSC. The electrical properties of the fabricated solar cells were investigated by measuring the current density voltage (J–V) under both darkness and illumination conditions. It was found that there is a significant improvement in the performance of DSSC used WO3 nanorods. References 1 M. Grätzel, Journal of Photochemistry and Photobiology Photochemistry R eviews 4, 145–153 (2003). 2 S. M. Yong, T. Nikolay, B. T. Ahn, D. K. Kim, Journal of Alloys and Compounds 54, 113–117(2013). 3 F.G. Wang, C. Di Valentin, G. Pacchioni, Chemcatchem 4 476–478(2012). 4 H.D. Zheng, Y. Tachibana, K. Kalantar-zadeh, Langmuir 26 19148–19152 (2010). 5 G. Wang, W. Xing, S. Zhuo, Electrochimica Acta 66 , 151– 157. (2012). 6 S Berson., D. Bettignies., S. Bailly, S. Guillerez, B. Jousselme, Adv. Funct. Mater. 17, 3363–3370 (2007). 7 E. Kyamakis, E. Stratakis, E. Koudoumas, Thin Solid Films 515 8598–8600(2007).

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