Projects / Programmes
Grafensko-organski supramolekularni funkcionalni kompoziti (Slovene)
| Code |
Science |
Field |
Subfield |
| 1.02.00 |
Natural sciences and mathematics |
Physics |
|
| Code |
Science |
Field |
| 1.03 |
Natural Sciences |
Physical sciences |
Researchers (5)
Organisations (1)
| no. |
Code |
Research organisation |
City |
Registration number |
No. of publicationsNo. of publications |
| 1. |
1540 |
University of Nova Gorica |
Nova Gorica |
5920884000 |
14,063 |
Significance for science
The GOSPEL project represents a milestone in the attempt to improve the detection limit of the dopant effects on the charge transport in graphene layers. We published our research on effects of the 1-pyrene butyric acid (PBA) on the charge transport in reduced graphene oxide (rGO) in the scientific article in Organic electronics [COBISS.SI-ID 2734075]. Our results were compared to theoretical calculations, which were performed at UMO. These calculations indicated that the interaction between PBA molecule and graphene results in a reduced charge transfer (only 0.06 e/dimer, e is unit of charge). However the PBA adsorption on rGO exhibits a significant change of charge transport properties. We discovered this fact by analyzing the time dependence of time-of-flight photoconductivity (TOF) current I(t). Analysis is strongly connected to our findings, published in Applied Physics Letters [COBISS.SI-ID 2495227], where we present the model of TOF I(t) time dependence. That is the I(t) curve, obtained by TOF measurements between coplanar electrodes, reflects the transit time of the 10% of the fastest carriers. These carriers are extremely sensitive to the distribution of charge traps in the examined layer. When graphene is coated with a submonolayer of organic molecules, which cause charge transfer, the shallow trap levels are formed in graphene (few tenths of eV below the lowest free orbital). Therefore, charge carriers in graphene are trapped in these shallow traps. Trapping time is comparable to the time of the measurement. These shallow trap levels are populated with the first photogenerated carriers that drift through graphene. Although the amount of the fastest carriers is low, their change of average velocity significantly change the shape of I(t) curve. In the presence of shallow trap levels, I(t) signature of transit time is observed to shift to longer times. As this is extremely sensitive to the density of trapping levels, we were able to detect the effect of doped molecules at the coverage as low as 0.08% of graphene surface. This achievement represents by far the most sensitive detection of adsorbed molecules.
Significance for the country
The GOSPEL project was financed by the European Science Foundation (ESF). At its launch, the GOSPEL project was the first one ESF financed. The consortium of GOSPEL project comprised also a Slovenian partner. More, GOSPEL was one of only few projects in Slovenia, which were focused to the graphene materials. In the framework of GOSPEL project, the Laboratory of Organic Matter Physics (LFOS) was able to finance one doctoral student, who will defend his doctoral dissertation in the May of 2014. Collaborating with the partners in the project, we made strong connections to the most prominent research laboratories of Europe, which are focused on the graphene research. Among them, we would like to stress the connection with Prof. dr. Kaus Müllen from the Max Planck Institut Mainz, Germany, which is one of the leading laboratories for the synthesis of organic semiconducting molecules and graphene materials. The Slovenian participation in GOSPEL undoubtedly promoted Slovenia as an advanced research focused country in the field of novel materials. Such promotion was achieved by organizing an international graphene workshop. The workshop took place in Ajdovščina from 8th to 11th of April 2013. The workshop was a successful and hosted the scientists from the most prominent worldwide institutions including CNR Bologna (Italy), ICM Madrid (Spain), Chalmers University (Sweden), and Texas Instruments Incorporated (USA).
Most important scientific results
Annual report
2010,
final report,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2010,
final report,
final report,
complete report on dLib.si
