Optoelektronik uygulamalar için fenantren-imidazol içeren konjüge kopolimerlerin sentezi ve karakterizasyonu.

Benzodithiophene and flourene represent tremendous promise as donor moieties in donor-acceptor approach for optoelectronic applications. The strong intermolecular π-π stacking, coplanar and rigid structure as well as symmetric configuration of these moieties enhance charge mobility and reduce band gap when incorporate in back bone of polymer within pull and push system. In order to decrease angle torsion and adjusting the optoelectronic properties of polymers, chalcogenophenes utilize as bridge between donor and acceptor. In this study, three different phenanthro imidazole containing conjugated copolymers (P1,P2 and P3) were synthesized using benzodithiophene and flourene via Suzuki and Stille condensation reactions. The structural characterizations of polymers were performed by NMR and the molecular weight of these polymers was measured via GPC. P1 utilized as active layer in single layer organic light emitting diode with device structure of ITO/PEDOT:PSS/P1/LiF:Al. The observed color was cyan with luminance of 5560 cd/m2 at 13 volts. For photovoltaic application P2 and P3 were used as active layer with device structure of ITO/PEDOT:PSS/Polymer:PC71BM/Ca:Al. The best of OPVs devices showed 0.94% PCE for P2 and 0.91% for P3 under standard AM 1.5 (100 mW/cm2) condition. M.S. - Master of Scienc

Altın yüzeyler üzerinde kendiliğinden düzenli tekkatlı karışım karborantiyol filmleri.

Thiolated derivatives of dicarba-closo-dodecaborane, HS-C2B10H11 (carboranethiols, CTs), with icosahedral molecular structure are one of the promising candidates for self-assembled monolayer (SAM) applications. CT SAMs possess various advantages relative to organic counterparts, such as high stability towards chemical, oxidative and thermal degradations as well as having fewer defects. In this study, pure and mixed SAMs of three different positional isomers of carboranethiols (namely M1, O1 and M9) on template stripped gold surfaces were grown from solution and characterized. Global properties of the SAMs were studied by means of contact angle (CA) and ellipsometric spectroscopy measurements. The ellipsometric thickness of all SAMs were found to be about 1 nm which is consistent with the reported thickness, measured by scanning tunneling microscopy, in the literature. In case of pure SAMs, M1 was observed to have the highest CA (85.4±1.8) whereas O1 SAMs have the lowest CA value (71.2±0.7). The dominant component that governs surface wettability was found to be M1 in mixed M1:M9 and O1:M1 SAMs. This is due to head to tail dipole-dipole interactions of M1 molecules on the surface. In case of M1:M9 co-deposited SAMs, CA was observed to increase with increasing M1 concentration in the growth solution. Such a clear trend was only present, however, in the advancing CAs for O1:M1 codeposited SAMs. On the other hand, contact angles of O1:M9 co-deposited films were observed to increase linearly with increasing M9 ratio in the growth solution. The morphological properties of the SAMs were investigated by atomic force microscopy and all SAMs were found to have similar properties with the exception of low defect concentration observed for O1:M9 films.  M.S. - Master of Scienc

Mixed carboranethiol self-assembled monolayers on gold surfaces

Carboranethiol self-assembled monolayers on metal surfaces have been shown to be very convenient systems for surface engineering. Here we have studied pure and mixed self-assembled monolayers (SAMs) of three different carboranethiol (CT) isomers on gold surfaces. The isomers were chosen with dipole moments pointing parallel to (m-1-carboranethiol, M1), out of (m-9-carboranethiol, M9) and into (1-carboranethiol, 01) the surface plane, in order to investigate the effect of dipole moment orientation on the film properties. In addition, influence of the substrate surface morphology on the film properties was also studied by using flame annealed (FA) and template stripped (TS) gold surfaces. Contact angle measurements indicate that in M1/M9 and M1/01 mixed SAMs, M1 is the dominant species on the surface even for low M1 ratio in the growth solution. Whereas for 01/M9 mixed SAMs no clear evidence could be observed indicating dominance of one of the species over the other one. Though contact angle values were lower and hysteresis values were higher for SAMs grown on TS gold surfaces, the trends in the behavior of the contact angles with changing mixing ratio were identical for SAMs grown on both substrates. Atomic force microscopy images of the SAMs on TS gold surfaces indicate that the films have similar morphological properties regardless of mixing ratio

Mixed carboranethiol self-assembled monolayers on gold surfaces

Carboranethiol self-assembled monolayers on metal surfaces have been shown to be very convenient systems for surface engineering. Here we have studied pure and mixed self-assembled monolayers (SAMs) of three different carboranethiol (CT) isomers on gold surfaces. The isomers were chosen with dipole moments pointing parallel to (m-1-carboranethiol, M1), out of (m-9-carboranethiol, M9) and into (1-carboranethiol, 01) the surface plane, in order to investigate the effect of dipole moment orientation on the film properties. In addition, influence of the substrate surface morphology on the film properties was also studied by using flame annealed (FA) and template stripped (TS) gold surfaces. Contact angle measurements indicate that in M1/M9 and M1/01 mixed SAMs, M1 is the dominant species on the surface even for low M1 ratio in the growth solution. Whereas for 01/M9 mixed SAMs no clear evidence could be observed indicating dominance of one of the species over the other one. Though contact angle values were lower and hysteresis values were higher for SAMs grown on TS gold surfaces, the trends in the behavior of the contact angles with changing mixing ratio were identical for SAMs grown on both substrates. Atomic force microscopy images of the SAMs on TS gold surfaces indicate that the films have similar morphological properties regardless of mixing ratio