Light-Induced Demixing of Hole or Electron Transporting Moieties Marc Behl, 1 Rudolf Zentel,* 1 Dick J. Broer* 2 1 Department of Organic Chemistry, University of Mainz, D-55099 Mainz, Germany E-mail: zentel@uni-mainz.de 2 Philips Research Laboratories, NL-5656AA Eindhoven, Netherlands E-mail: dick.broer@philips.com Received: July 19, 2004; Revised: August 26, 2004; Accepted: August 30, 2004; DOI: 10.1002/marc.200400321 Keywords: conducting polymers; demixing; photopolymerization; triazine; triphenylamine Introduction In the last few years much progress has been achieved in developing organic semiconducting materials for electronic applications like organic light-emitting diodes (OLEDs), photovoltaics, or field effect transistors (FETs). [1–3] For their operation it is necessary to structure the material and to create p-n junctions in various ways: [4,5] For most OLEDs, a two- or three-layer structure is desired, for photovoltaics a bicontinous nanophase of separated structures from p- or n-conducting material, and for plastic electronics an engi- neered pattern of p- and n-conducting areas to create diodes ‘‘at will’’. Such structures can be made, e.g., by multistep processes, in which one material (p- or n-conducting) is applied first, patterned and partly removed (if necessary) before the second material is applied. A one-step process by which p- and n-conducting materials are patterned simultaneously would be very advantageous. Nanophase-separated block-copolymers of p- and n-conducting monomers allow the one-step creation of p-n junctions, [6] however, they cannot be engineered afterwards. A possibility to phase separate a binary mixture of monomers with preferential hole or electron transport properties ‘‘at will’’ may lead to the desired pattern of p- or n-conducting materials. This might be achieved by taking advantage of the different polymerization reactivities of two monomers in combination with a spatially controlled creation of radicals. Broer et al. could show that liquid crys- tals of different reactivity demix spatially during polymer- ization in a light gradient. [7–11] Here we present the synthesis of two new monomers with preferential hole (p)- or electron (n)-conducting properties, Summary: This paper describes the synthesis of two tri- phenylamine monomers (hole conducting) and one triazine monomer (electron conducting) which differ in their copoly- merization parameters because of their styrene and vinyl ester nature. A blend of triphenylamine monomer and poly- (ethylene glycol) and mixtures of both types of monomers (triphenylamine and triazine) were illuminated through a line mask, creating laterally modulated radicals, thus leading to lateral demixing. The experiments with mixtures of triphe- nylamine and triazine monomers show that the concentration of p- or n-type polymers can be modulated laterally in a controlled way. AFM measurement of line pattern formed by illuminating a mixture of monomer 2 and 3 showing the height difference between illuminated and non-illuminated areas. Macromol. Rapid Commun. 2004, 25, 1765–1770 DOI: 10.1002/marc.200400321 ß 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Communication 1765