Highly transparent, low-haze, hybrid cellulose nanopaper as electrodes for flexible electronics.
Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are still characterized by high diffuse transmittance and small direct transmittance, resulting in high optical haze of the substrates. In this study, we proposed a simple methodology for large-scale production of high-transparency, low-haze CNP comprising both long cellulose nanofibrils (CNFs) and short cellulose nanocrystals (CNCs). By varying the CNC/CNF ratio in the hybrid CNP, we could tailor its total transmittance, direct transmittance and diffuse transmittance. By increasing the CNC content, the optical haze of the hybrid CNP could be decreased and its transparency could be increased. The direct transmittance and optical haze of the CNP were 75.1% and 10.0%, respectively, greatly improved from the values of previously reported CNP (31.1% and 62.0%, respectively). Transparent, flexible electrodes were fabricated by coating the hybrid CNP with silver nanowires (AgNWs). The electrodes showed a low sheet resistance (minimum 1.2 Ω sq(-1)) and a high total transmittance (maximum of 82.5%). The electrodes were used to make a light emitting diode (LED) assembly to demonstrate their potential use in flexible displays.
North Dakota State University, Department of Mechanical Engineering, USA and Program of Materials and Nanotechnology, Fargo, ND 58102, USA. long.jiang@ndsu.edu and King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Mechanical Engineering, COHMAS Laboratory, Thuwal 23955-6900, Saudi Arabia. gilles.lubineau@kaust.edu.sa.
Xuezhu
X
Xu
King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Mechanical Engineering, COHMAS Laboratory, Thuwal 23955-6900, Saudi Arabia. gilles.lubineau@kaust.edu.sa.
Jian
J
Zhou
North Dakota State University, Department of Mechanical Engineering, USA and Program of Materials and Nanotechnology, Fargo, ND 58102, USA. long.jiang@ndsu.edu.
Long
L
Jiang
King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Mechanical Engineering, COHMAS Laboratory, Thuwal 23955-6900, Saudi Arabia. gilles.lubineau@kaust.edu.sa.
Gilles
G
Lubineau
King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Electrical Engineering, Photonics Laboratory, Thuwal 23955-6900, Saudi Arabia.
Tienkhee
T
Ng
King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Electrical Engineering, Photonics Laboratory, Thuwal 23955-6900, Saudi Arabia.
Boon S
BS
Ooi
King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Electrical Engineering, Photonics Laboratory, Thuwal 23955-6900, Saudi Arabia.
Hsien-Yu
HY
Liao
King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Electrical Engineering, Photonics Laboratory, Thuwal 23955-6900, Saudi Arabia.
Chao
C
Shen
King Abdullah University of Science and Technology (KAUST), Advanced Nanofabrication, Imaging and Characterization Core Laboratory, Thuwal 23955-6900, Saudi Arabia.
Long
L
Chen
Forest Products Laboratory, USDA Forest Service, Madison, Wisconsin 53726, USA.
J Y
JY
Zhu