Biodegradable transparent substrates for flexible organic-light-emitting diodes

Abstract

Electronics on flexible and transparent substrates have received much interest due to their new functionalities and high-speed roll-toroll manufacturing processes. The properties of substrates are crucial, including flexibility, surface roughness, optical transmittance, mechanical strength, maximum processing temperature, etc.Although plastic substrates have been used widely in flexible macroelectronics, there is still a need for next-generation sustainable, high-performance substrates which are thermally stable with tunable optical properties and a higher handling temperature. In this communication, we focus on cellulose-based transparent, biodegradable substrates incorporating either nanopaper or a regenerated cellulose film (RCF). We found that both their optical and mechanical properties are dramatically different due to the difference of their building blocks. Highly flexible organic-light-emitting diodes (OLEDs) are also demonstrated on the biodegradable substrates, paving the way for next-generation green and flexible electronics.

A flexible solar-blind 2D boron nitride nanopaper-based photodetector with high thermal resistance

“…The oxidation process was carried out by adding 78 mg of 2,2,6,6-tetramethylpiperidine-1-oxyl and 514 mg NaBr to 5 g kraft bleached softwood pulp into 12% NaClO solution with a pH of 10.5 (controlled by adding NaOH). 31 After oxidation, deionized water was added to the oxidized product to prepare a 1 wt% cellulose suspension. The suspension was then processed by a microfluidizer (M-110EH, Microfluidics Ind.)…”

“…Next, the suspension was disintegrated by a microfluidizer to achieve the fine NFC suspended material. The NFC, composed of fibrils featuring a diameter ranging from 5 to 100 nm, 31 formed the basis of the flexible nanopaper substrates.…”

Thin-film organic semiconductor devices: from flexibility to ultraflexibility

“…For achieving higher efficiency, top-emitting architectures [182][183][184][185] and nanostructured/scattered electrodes or substrates [47,[130][131][132][133][134][135] can be adopted, to enhance output coupling or light extraction of the devices. However, to achieve high flexibility, extremely bendable TFC electrodes firstly need to be developed [88,120,124,146,147,177,186]. Yu et al [120] developed an AgNWs/shape-memory-polymer composite electrode deposited on PET substrate on which a flexible yellow OLED with minimum R b of 2.5 mm has been constructed.…”

What do we still need to understand to commercialize cellulose nanomaterials?†

“…Over the past decade, numerous applications for CNM have been developed and investigated worldwide. [1][2][3][4][5][6][7][8][9][10] Cellulose nanocrystals (CNC) were first isolated in the laboratory by Mukherjee and Woods in 1953, 11 and a commercially scalable process for cellulose nanofiber (CNF) production was invented by ITT Rayonier in 1977. 12,13 Since then, several inventions and techniques have led to the development of pilot-scale production methods which have been implemented across the globe (CelluForce in Canada, American Process, Inc. in the United States of America and Innventia in Sweden to name a few).…”

“…In their neat form, CNM have optical properties which result in transparent films or papers. 1,3 Under specific circumstances, CNC self-assemble into a chiral nematic crystalline order, thus having the potential to impart structural color to coated objects. 24,25 The unique surface properties of CNC, particularly, have been investigated both theoretically and experimentally.…”