Molybdenum-oxide hole transport layers for organic electronics

At SDU NanoSYD, University of Southern Denmark, reactive sputtering of Molybdenum oxide thin-films are conducted in order to develop metal-oxide films with tunable opto-electronic properties. By controlling the flow of oxygen during the sputtering process, it has been demonstrated that the composition of the resulting films, and thus also the optical and electrical properties can be tuned from transparent to opaque, and from conductive to insulating, respectively. In addition, by conducting a UHV annealing step following growth, it is possible to crystallize the films, leading to large change in work function of the films. In a recent publication, the researcher demonstrate that its possible to vary the work function by almost 2 eV, reaching values close to those of single crystalline Molybdeum oxide (6.9eV). The high work function films can be developed on device relevant substrates, which therefore makes them highly relevant as transport layers in for example photovoltaic devices, which is pursued as the next step by the researchers.

• A. L. F. Cauduro, R. dos Reis, G. Chen, A. K. Schmid, H.-G. Rubahn and M. Madsen, “Work Function Mapping of MoOx Thin-Films for Application in Electronic Devices”, Ultramicroscopy, (2017)
• A. L. F. Cauduro, R. dos Reis, G. Chen, A. K. Schmid, C. Méthivier, H.-G. Rubahn, L. Bossard-Giannesini, H. Cruguel, N. Witkowski and M. Madsen, “Crystalline Molybdenum Oxide Thin-Films for Application as Interfacial Layers in Optoelectronic Devices”, ACS Appl. Mater. Interfaces, 9, 7717 (2017)