1902080 (1 of 8) © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.advopticalmat.de COMMUNICATION Gap Plasmon of Virus-Templated Biohybrid Nanostructures Uplifting the Performance of Organic Optoelectronic Devices Hock Beng Lee, Won-Geun Kim, Miso Lee, Jong-Min Lee, Siwei He, Neetesh Kumar, Vasanthan Devaraj, Eun Jung Choi, Il Jeon, Myungkwan Song, Jin-Woo Oh,* and Jae-Wook Kang* DOI: 10.1002/adom.201902080 short-wavelength region of light (≈300 nm) and its efect can be further enhanced if the NPs are i) densifed into complex molecules and structures or ii) localized by a certain distance among them to induce gap-plasmon efect. Through this gap- plasmon efect, the light absorption can be amplifed even in the long-wavelength region of light (≈600 nm). Novel materials that yield gap-plasmon efect are particularly desirable for optoelectronic devices which generally exhibit greater light to current efciency in the long-wavelength region. [5,6] However, the gap-plasmon enhancement in optoelectronics has been extremely chal- lenging to induce due to the lack of an efec- tive medium to precisely control the NP position. [7] A suitable nanoscale template or scafold that is capable of holding the NPs apart at a nanoscale distance during the densifcation process is necessary to achieve this. [8,9] Unprecedentedly, we demonstrate a green, facile synthesis of biohybrid nano- structures using Ag/Au plasmonic NPs as sensitizers; and M13 bacteriophage as an environmental benign virus template. Genetically engineered M13 bacteriophage, with a length of ≈880 nm and diameter of 6.6 nm, could function as a biological scafold for the controlled assembly of NPs because of its flamentous geometry, [10–12] high aspect ratio, and outstanding chemical properties. [13–15] More importantly, the unique direction- ality and electrical polarity of M13 bacteriophage peptide receptors Plasmonic nanostructures, which exhibit prominent localized surface plasmon resonance (LSPR) properties, are highly desirable for organic solar cells (OSC) and organic light-emitting diode (OLED) devices. In the present work, novel plasmonic bio-nanostructures are successfully synthesized via the self-densifcation of silver (Ag) and gold (Au) metallic nanoparticles (NPs) onto a genetically engineered M13 bacteriophage template. Owing to the unique charge selectivity of the peptide receptors on the M13 bacteriophage, the metallic NPs can be directly anchored onto the bacteriophage through charge-driven interactions without binder/surfactant. The resulting Ag/AuNP- M13 bio-nanostructures display extraordinary gap-plasmon efect as well as tremendously enhanced LSPR properties than the randomly dispersed Ag/Au NPs. The incorporation of Ag/AuNP-M13 bio-nanostructures tremendously improves the performance of both OSC and OLED devices. Specifcally, a power conversion efciency increment of 15.5% is recorded for the phage- modifed OSCs; whereas an external quantum efciency increment of 22.6% is achieved for the phage-modifed OLEDs. Based on this environmentally benign virus-template approach, various plasmonic/photonic bio- nanostructures can be designed for diverse device applications. Dr. H. B. Lee, M. Lee, S. He, Dr. N. Kumar, Prof. J.-W. Kang Department of Flexible and Printable Electronics LANL-CBNU Engineering Institute-Korea Chonbuk National University Jeonju 54896, Korea E-mail: jwkang@jbnu.ac.kr W.-G. Kim, Prof. J.-W. Oh Department of Nano Fusion Technology Pusan National University Busan 46241, Korea E-mail: ojw@pusan.ac.kr The ORCID identifcation number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adom.201902080. Dr. J.-M. Lee, Dr. V. Devaraj, Dr. E. J. Choi, Prof. J.-W. Oh Research Center for Energy Convergence and Technology Pusan National University Busan 46241, Korea Prof. I. Jeon [+] Department of Mechanical Engineering The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Dr. M. Song Advanced Functional Thin Films Department Korea Institute of Materials Science Changwon 641-831, Korea Prof. J.-W. Oh Department of Nanoenergy Engineering Pusan National University Busan 46241, Korea Metallic nanoparticles (NPs) particularly silver (Ag) and gold (Au) NPs, which exhibit prominent localized surface plasmon reso- nance (LSPR) properties, are conventionally employed to enhance the light-harvesting efciency of optoelectronic devices. [1–3] Pri- marily, metallic NPs realize a plasmonic enhancement efect in optoelectronic devices by increasing the light-surface plasmon coupling. [4] Such LSPR phenomenon typically amplifes the [+] Present address: Department of Chemistry Education, Graduate School of Chemical Materials, Pusan National University, Busan 46241, South Korea Adv. Optical Mater. 2020, 1902080