Regensburg 2004 – scientific programme
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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 5: Poster
SYOH 5.39: Poster
Thursday, March 11, 2004, 18:00–21:00, B
Organic pn-homojunction using a new class of organic donors — •K. Harada1, A.G. Werner1, M. Pfeiffer1, K. Leo1, C. Bloom2, and C.M. Elliott2 — 1Institut für Angewandte Photophysik, TU Dresden, D-01062 Dresden — 2Dep. of Chemistry, Colorado State University, Fort Collins, CO 80523
Organic devices with p-type doped hole transport layers are now well established. So far, n-type doped electron transport materials have been realized with alkali metals as dopants only, because the common matrices are rather weak electron acceptors. This demands for donor compounds with a very low ionization potential, which are generally difficult to handle. This limitation seemingly prevented n-type doping using very strong organic donors.
We present a study of n-type doping of phthalocyanine zinc (ZnPc) using metalorganic complexes as donors. ZnPc is generally considered as a p-type semiconductor. However, using the transition metal complexes as donors, we are able to achieve n-type conduction in this material. Conductivies in the order of 10−6 S/cm are observed and the conduction type was confirmed by field effect measurements.
This enabled us to realize the first stable organic p-n junctions constisting of p- and n-type doped layers of the same material (homo-junctions). They have very high built-in potentials. This does not only reflect the versatility of doping in organic devices, but pave a way to increase the open circuit voltage of organic solar cells and to use n-type doped electron transport layers in OLEDs.