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.
- 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