Arif Kösemen

Poly(3-Methylthiophene) Thin Films Deposited Electrochemically on QCMs for the Sensing of Volatile Organic Compounds.

Poly(3-methylthiophene) (PMeT) thin films were electrochemically deposited on quartz crystal microbalance QCM transducers to investigate their volatile organic compound (VOC) sensing properties depending on ambient conditions. Twelve different VOCs including alcohols, ketones, chlorinated compounds, amines, and the organosphosphate dimethyl methylphosphonate (DMMP) were used as analytes. The responses of the chemical sensors against DMMP were the highest among the tested analytes; thus, fabricated chemical sensors based on PMeT can be evaluated as potential candidates for selectively detecting DMMP. Generally, detection limits in the low ppm range could be achieved. The gas sensing measurements were recorded at various humid air conditions to investigate the effects of the humidity on the gas sensing properties. The sensing performance of the chemical sensors was slightly reduced in the presence of humidity in ambient conditions. While a decrease in sensitivity was observed for humidity levels up to 50% r.h., the sensitivity was nearly unaffected for higher humidity levels and a reliable detection of the VOCs and DMMP was possible with detection limits in the low ppm range.

TiO-Based Organic Hybrid Solar Cells with Mn

A hybrid solar cell is designed and proposed as a feasible and reasonable alternative, according to acquired efficiency with the employment of TiO2 (titanium dioxide) and Mn-doped TiO2 thin films. In the scope of this work, TiO2 (titanium dioxide) and Mn:TiO2 hybrid organic thin films are proposed as charge transporter layer in polymer solar cells. Poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT: PCBM) is used as active layer. When the Mn-doped TiO2 solar cells were compared with pure TiO2 cells, Mn-doped samples revealed a noteworthy efficiency enhancement with respect to undoped-TiO2-based cells. The highest conversion efficiency was obtained to be 2.44% at the ratio of 3.5% (wt/wt) Mn doping.