Highly efficient modulation doping: A path toward superior organic thermoelectric devices

• DOI: 10.1126/sciadv.abl9264
• Publication Date: 2022-03-30T17:57:25Z
• Authors: Shu-Jen Wang; Michel Panhans; Ilia Lashkov; Hans Kleemann; Federico Caglieris; David Becker-Koch; Jörn Vahland; Erjuan Guo; Shiyu Huang; Yulia Krupskaya; Yana Vaynzof; Bernd Büchner; Frank Ortmann; Karl Leo
• Keywords: Physical and Materials Sciences; -; 02 engineering and technology; 0210 nano-technology; ddc:

We investigate the charge and thermoelectric transport in modulation-doped large-area rubrene thin-film crystals with different crystal phases. We show that modulation doping allows achieving superior doping efficiencies even for high doping densities, when conventional bulk doping runs into the reserve regime. Modulation-doped orthorhombic rubrene achieves much improved thermoelectric power factors, exceeding 20 μW m −1 K −2 at 80°C. Theoretical studies give insight into the energy landscape of the heterostructures and its influence on qualitative trends of the Seebeck coefficient. Our results show that modulation doping together with high-mobility crystalline organic semiconductor films is a previosly unexplored strategy for achieving high-performance organic thermoelectrics.