Flexible and Transparent Organic Phototransistors on Biodegradable Cellulose Nanofibrillated Fiber Substrates

Junsu Park, Jung Hun Seo, Seung Won Yeom, Chunhua Yao, Vina W. Yang, Zhiyong Cai, Young Min Jhon, Byeong Kwon Ju

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)


This work demonstrates flexible, transparent phototransistors that can detect visible light with nontoxic organic active materials on biodegradable substrates toward environment-friendly electronics. The molybdenum trioxide (MoO3)-buffered indium zinc oxide as high-performance hole injector and transparent electrodes is applied for the first time to organic phototransistors on cellulose nanofibrillated fiber substrates to achieve more than 70% of transmittance in the visible range (400–750 nm) while showing high conductivity under multiple bendings. Excellent electrical switching characteristics are obtained from transistors using a pentacene active layer with a saturation mobility value of 1.40 cm2 V−1 s−1. The phototransistors, which can detect visible light and perform in two operation modes, exhibit a maximum responsivity of 54.8 A W−1 and a photosensitivity of 24.4 under white light illumination at an intensity of 0.12 mW cm−2. Moreover, the devices show a stable operation during mechanical bending tests with radii ranging from 100 to 5 mm and cyclic bending tests of up to 2000 cycles at a fixed radius of 5 mm. The results suggest that these flexible phototransistors with properties of transparency and biodegradability have considerable potential for use in low-cost and eco-friendly disposable sensor systems.

Original languageEnglish
Article number1701140
JournalAdvanced Optical Materials
Issue number9
Publication statusPublished - 2018 May 7

Bibliographical note

Funding Information:
J.P. and J.-H.S. contributed equally to this work. This work was supported by the KSSRC program (Stretchable Multi Sensor for Wearable IoT Device) and the KIST Institutional Program (Project No. 2E28280). This work was partly supported by the R&D program of MOTIE/KEIT [10064078, Development of the Multi-Sensor for UV, Ambient Light, and Proximity for Next Smart Device] and the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIP) (No. 2016R1A2B4014073). The work was partly supported by the New York State Center of Excellence in Materials Informatics (CMI) program and the University at Buffalo Innovative Micro-Programs Accelerating Collaboration in Themes (IMPACT) program.

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • biodegradation
  • flexible sensors
  • indium zinc oxide electrodes
  • organic phototransistors
  • thin-film transistors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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