SYNTHESIS AND CHARACTERIZATION OF NEW ORGANIC MOLECULES AND INORGANIC-ORGANIC HYBRID MATERIALS WITH INTERESTING LINEAR AND SECOND ORDER NON LINEAR OPTICAL PROPERTIES
Tesi di Dottorato
Data di Pubblicazione:
2010
Citazione:
SYNTHESIS AND CHARACTERIZATION OF NEW ORGANIC MOLECULES AND INORGANIC-ORGANIC HYBRID MATERIALS WITH INTERESTING LINEAR AND SECOND ORDER NON LINEAR OPTICAL PROPERTIES / E. Tordin ; Tutor: Renato Ugo ; Co-tutor: Elena Cariati. Università degli Studi di Milano, 2010 Dec 10. 23. ciclo, Anno Accademico 2010. [10.13130/tordin-elisa_phd2010-12-10].
Abstract:
The different stages of technological evolution are characterized in terms of the dominant type of tools used in each of them. We passed through the `stone age', the `copper age' and the `iron age' and now we are probably in the `electron age'. After having done a wonderful job, today it looks as if electronic technologies have started experiencing their limits. For example, today's `information explosion' and communication problems demand very large bandwidths without cross talk, larger than that electronics can provide. What could be the technology that can tackle the growing needs of tomorrow?
Photonics is being studied today as a possible alternate technology for the future. Investigations are on to harness the capability of the photon to carry information and energy. Fortunately, success has already been achieved in the area of communications. Optical fibers, not copper cables, are already being used to carry huge amounts of information across the great oceans. However, among the three “C”s (communication, computing and control), communication is the only one that is currently implying photonic devices. Photonic switches and optical computers are still in the laboratories and not yet in the marketplace. The major bottleneck in this area is not in solving technological problems or in perfecting theoretical understanding, but in developing suitable materials.
In this field, materials with non linear optical (NLO) properties seem to be extremely appealing in fact NLO effects allow the manipulation of laser light beams, extending the frequency range provided by normal laser sources into the ultraviolet and infrared regions, and may thus form the basis of all-optical computing devices.
In order to be implied in a device, the NLO materials must satisfy some requirement such as good NLO properties, high laser damage threshold, fast optical response time, wide phase matchable angle, architectural flexibility for molecular design and morphology, ability to process into crystals and thin films, optical transparency (no absorption at fundamental and SH wavelengths), synthetically facile, environmental friendly and high mechanical strength and thermal stability.
During this three-year research the attention was to the synthesis and the investigation of the second harmonic NLO properties of new organic and inorganic-organic hybrid material.
NLO characterization has been performed in solution using the EFISH technique, the Kurtz-Perry method has been implied for the measurements in the solid state while the Maker’s fringe technique has been use for measurements on film.
In the field of inorganic-organic hybrid materials, the synthesis of new members of the family of compounds with general formula [DAMS]4[MIII2MII(C2O4)6]2•DAMBA•2H2O (where MIII = Rh, Fe, Cr; MII = Co, Ni, DAMS = trans-4-(4-dimethylaminostyryl)-1-methylpyridinium; DAMBA = para-dimethylamino benzaldeide) has been prepared and, in particular, the derivatives containing CoII and NiII have been isolated by slight modification of the synthesis reported by Cariati et al. for the MnII and ZnII derivatives. The SHG of these new materials is extremely high, of the same order on magnitude of DAST (trans-4-(4-dimethylaminostyryl)-1-methylpyridinium p-toluensulfonate) and it is related to the organization into J aggregates of the [DAMS+] chromophores. These materials are not only interesting for their SHG but also for the tuning of their magnetic properties by varying the MII/MIII couple.
During the optimization of the synthesis of these compounds, a phase containing only [DAMS]I and DAMBA has been isolated. The [DAMS+] chromophores are organized in colums in a configuration typical of J aggregates and the presence of the templating agent DAMBA induces the arrangement
Tipologia IRIS:
Tesi di dottorato
Keywords:
NLO ; SHG ; J aggregates ; EFISH ; CIE
Elenco autori:
E. Tordin
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