The derivatives of boradiazaindacene (BODIPY) are highly fluorescent dyes which have quantum yields near 1.0. These dyes that have exceptional spectral and photophysical stability as compared to other fluorescent groups are used for several different applications. The fluorescent sensor molecules for the detection of cations with PET (photoinduced-electron transfer) mechanism in general have been obtained by the differentiation of the BODIPY core. The extension of conjugation over the pyrrole ring shifts the absorption and emission at longer wavelength. Moreover, it is seen that red emission occurs from an ICT (intramolecular-charge transfer) state. iii In this study, we designed and synthesized an unsymetrically substituted BODIPY dye series, carrying a cation-sensitive phenylazacrown ether group conjugated to the core, and investigated the ion sensing properties of these compounds. Both aza-crown derivatives displayed selectivity towards Ca(II).

The aim of this diploma thesis is to conduct optical and photovoltaic characterization of derivatives of diketopyrrolopyrrole (DPP) as materials suitable for fabrication of bulk heterojunction organic solar cells. The charge transfer from donor material (DPP) to acceptor material (PCBM) is studied by a quenching of fluorescence. The photovoltaic response is studied by current – voltage characteristic which can tell us crucial parameters such as shor circuit current density Jsc, open circuit voltage Voc, fill factor FF and power conversion efficiency PCE. Optical characterization was carried out for symmetrical DPP derivatives (U69 and U97) which both contained diphenylaminstilbene moiety and differed in N-alkyl group. On the other hand photovoltaic characterization was conducted for analogous but asymmetrical materials (U70 and U99). Material U29 was characterized as well but its properties proved to be very poor. Both these characterizations tell us that materials with shorter solubilization groups (U69 and U99) are more suitable candidates. Achieved PCE for U70 was 0,74 % and for U99 up to 1,39 %. From these values one can say that small molecule organic materials can be used for fabrication of solar cells.