Optical and Morphological Characterization of PTCDI-C13
- PDF / 386,933 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 107 Downloads / 240 Views
1091-AA05-40
OPTICAL AND MORPHOLOGICAL CHARACTERIZATION OF PTCDI-C13 Marco Stella1, Fernando Villar1, Fredy Enrique Rojas1, Mónica Della Pirriera2, Cristobal Voz2, Joaquim Puigdollers2, José Miguel Asensi1, Jordi Andreu1, and Joan Bertomeu1 1 Física Aplicada i Òptica, Universitat de Barcelona, Barcelona, 08028, Spain 2 Enginyeria Electrònica, Universitat Politècnica de Catalunya, Barcelona, 08034, Spain ABSTRACT The organic photovoltaic technology has developed much in the last few years thanks to the optimization of the solar cell geometry and, specially, to the research for new performing materials. Nevertheless, much work has still to be done in order to better know the real mechanisms regulating the function of such novel class of semiconductors. The study of thinfilm micro-structure, and the influence of the deposition parameters on it, is an important issue in order to obtain best optical and electrical properties. Thermal evaporation in high-vacuum chambers is the more suitable deposition technique to obtain organic thin-films with well organize molecular structure. Deposition parameters such as the substrate temperature and deposition rate may have some important effect on the molecules ordering. In this paper the effects of substrate temperature on structural and optical properties have been studied for N,N´ditridecyl perylene diimide (PTCDI-C13) thin-films. Four samples have been deposited at 30, 60, 90 and 120ºC substrate temperature and their absorption has been investigated by photothermal deflection spectroscopy (PDS) and transmittance spectroscopy. Moreover, simulations of the transmittance spectra have been calculated in order to obtain the optical constants n and k. Finally atomic force microscopy (AFM) has been employed to analyze the superficial morphology of the thin-films.
INTRODUCTION Organic semiconductors have revealed as a promising class of materials for several electronic applications. Flexibility, low weight and low cost production make them an interesting alternative class of semiconductors [1]. Moreover, the great number of different materials that are available and the possibility to project new ones justify the expectation for research on organic technology to obtain great advances in the future [2]. Finally, the deposition techniques offer a great variety of little expensive processes and easy ways to obtain large-area devices [3]. Among the molecular organic semiconductors N,N´-ditridecyl perylene diimide (PTCDI-C13) is a compound that belongs to the family of the perylenes, as well as the more known 3,4,9,10perylenetetracarboxylic dianhydride (PTCDA). Such class of materials are acceptor type (n-type) and has reached much attention during the last few years [4,5,6] since values of field-effect electron mobility as high as 0.6 [7] and 1 cm2V-1s-1 [8] have been demonstrated for them. In Figure 1 the structure formula of PTCDI-C13 is shown.
Figure 1. Molecular structure of PTCDI-C13.
The alkyl chains, which characterize PTCDI-C13 in comparison with PTCDA and PTCDI, give self-asse
Data Loading...
