Abstract: An in-depth insight in the molecular and crystalline properties of organic semiconductors, and a high and reproducible degree of control on the growth processes are needed to open the possibility of exploiting these features for laser devices, and possibly for achieving tuneability of the resulting emission. In particular, in view of current injection, using high-quality crystals may be a novel strategy of breakthrough impact, providing much more advantages than amorphous films involving defects that act as carrier traps. In our project, we target the realization of novel laser devices using crystalline organic semiconductors as active gain media, and specifically designed and implemented nanolithography approaches to induce the feedback needed for lasing action. The objectives of the project are:
(1) the implementation and development of growth and deposition techniques for organic semiconductor crystals, and polycrystalline samples of controlled concentration of contaminants and degree of order (synthesis of grams of molecules with concentration of contaminants below 0.1%, growth of pure crystals with area of many mm2 and thickness of a few micrometers, deposition of films with thickness up to 1 micrometers on different substrates);
(2) the basic investigation of the relationship between the degree of crystalline order and the optical anisotropy of the realized crystals and films, and the achievable lasing performances from a wide range of grown molecules;
(3) the delivery of well-defined and reproducible nanofabrication protocols on organic semiconductor crystals, specifically designed for laser applications in the visible (range of resolutions 100 nm-2 micrometers);
(4) the realisation and optimisation of laser prototypes based on organic single crystals (expected threshold excitation densities of hundreds of microJ/cm2).

 

 

Department of Innovation Engineering National Nanotechnology Laboratory Soft Matter Nanotechnology Division University of Salento, Lecce	Department of Materials Science University of Milano Bicocca

 

For more information about the performed tasks on the Synthesis of Organic Semiconductor Crystals , such as Acridines , Oligothiophenes , and Rubrene , on the Crystals Characterization , and on the Laser Devices please click on the related links.