New Metal Oxides and Plasmonic Metal Nanostructures for Emerging Organic Optoelectronic Devices

Abstract

We theoretically and experimentally investigated OSCs incorporated with multiple plasmonic metal nanostructures. For the theoretical study, we employed a multiphysics model for plasmonic organic solar cells to investigate the detailed physics of the performance enhancement. Furthermore, experimental studies were also conducted on various metallic nanostructures such as metallic nanoparticles and metallic nanogratings embedded into different regions of the solar cells, with interesting plasmonic-optical and plasmonic-electrical effects observed. For the plasmonic-optical effects, light absorption in the active layer of OSCs was enhanced by the embedded plasmonic metal nanostructures, which thus improved the photocurrent of the device. For the electrical effects by the incorporated plasmonic nanostructures, hot carrier and charge storage effects were separately studied and organic optoelectronic devices with high performance were achieved. Through a novel plasmonic-electrical concept, we recently demonstrated the surpassing of the intrinsic space-charge limit in organic semiconductors. Charge extraction and injection through developing efficient charge transport layers is equally essential for the design of high performance optoelectronic devices. In order to further reduce production costs and enable compatibility with large-area and high-throughput production, it is highly desirable to develop solution-processed approaches for the synthesis of various charge transport layers. We demonstrated effective methods to synthesize various metal oxides as hole transport layer and electron transport layer for high performance organic optoelectronic devices, with the distinctive features of solution-processed and requiring only low- or even room-temperature. Using our approaches, the metal oxide charge transport layers with moderate level of oxygen vacancies showed excellent charge transport properties. By further incorporating metal nanomaterials, charge extraction in organic photovoltaic devices was significantly improved.