Electrical Properties of ITO/CdSe/P3OT/Metal Heterojunction
- PDF / 117,070 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 38 Downloads / 226 Views
I9.30.1
ELECTRICAL PROPERTIES OF ITO/CdSe/P3OT/Metal HETEROJUNCTION Oscar H.Salinas*,1, Hailin Hu1 , Ma.Elena Nicho-Díaz2 , Cecilia López-Mata1,3, Oscar GomezDaza1. 1 Centro de Investigación en Energía, UNAM, Av.Xochicalco S/N, Temixco,Morelos, 62580, México 2 CIICAp-Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos. 3 Instituto Tecnológico de Zacatepec, Zacatepec, Morelos. *e-mail: [email protected] Abstract. Conducting polymer based heterojunctions have been intensively studied because of their prominent application in photovoltaic solar cells. It is reported in this work the formation, under environmental conditions, of hybrid heterojunctions of cadmium selenide (CdSe) with poly3octylthiophene (P3OT) by casting a chemically synthesized P3OT solution onto either chemical bath deposited (CBD) or screen-printed (SP) CdSe coatings. By using ITO as back contact and gold (Au), silver (Ag) or copper (Cu) as metal contact, the electrical properties of CdSe–P3OT heterojunctions were studied at room temperature under environmental conditions. In the case of Au contact, the curves of current density (J) vs. applied potential (V) of both CdSe (SP) and CdSe (CBD) coatings indicate that the contacts are quasi ohmic. However, with the same metal contact the electrical behavior of CdSe (SP)-doped P3OT heterojunction becomes rectifying and the rectification ratio increases as the weight percentage of P3OT increases in the heterojunction structure. Furthermore, a small photovoltage (39 mV) was observed in the same hybrid structure for Cu contact. On the other hand, for a CdSe (CBD)-pristine P3OT heterojunction Au contact gives an ohmic behavior, but rectifying J-V curves are found with Cu contact. Keyword: Hybrid heterojunctions, CdSe, P3OT, photovoltaic effect, metal-semiconductor contact. 1. Introduction. Heterojunction structures have been used in the electronic industry to build different kind of devices in order to improve their performance for some specific applications, for example transistor, diode, optoelectronic devices, solar cells [1]. In 1986 Tang built an organic solar cell with a heterojunction structure that shows a significant improvement on energy power conversion efficiency (PCE) compared with the organic homojunctions [2]. Since then research interests on organic heterojunctions have been increased. P3OT for example, is a widely studied conducting polymer at laboratory level because of its attractive electron donor properties, relative stability in ambient and solubility in common organic solvents. However, due to the low electron mobility of conducting polymers, it is convenient to use them as electron donors. In order to combine the advantage of different kinds of semiconductor materials, hybrid heterojunctions based on conducting polymers and inorganic semiconductor materials are built. This is done in the aim of improving solar cell electrical performance. Chalcogenides materials like CdSe or CdS are suitable electronic materials to be used as electron acceptor layers in hybrid heterojunctions
Data Loading...
