Correction: Recent progress in controlled nano/micro cracking as an alternative nano-patterning method for functional applications.

Correction for 'Recent progress in controlled nano/micro cracking as an alternative nano-patterning method for functional applications' by Jinwook Jung et al., Nanoscale Horiz., 2020, DOI: .

Recent progress in controlled nano/micro cracking as an alternative nano-patterning method for functional applications.

Generally, cracking occurs for many reasons connected to uncertainties and to the non-uniformity resulting from intrinsic deficiencies in materials or the non-linearity of applied external (thermal, mechanical, etc.) stresses. However, recently, an increased level of effort has gone into analyzing the phenomenon of cracking and also into methods for controlling it. Sophisticated manipulation of cracking has yielded various cutting-edge technologies such as transparent conductors, mechanical sensors, microfluidics, and energy devices. In this paper, we present some of the recent progress that has been made in controlling cracking by giving an overview of the fabrication methods and working mechanisms used for various mediums. In addition, we discuss recent progress in the various applications of methods that use controlled cracking as an alternative to patterning tools.

Moiré-Free Imperceptible and Flexible Random Metal Grid Electrodes with Large Figure-of-Merit by Photonic Sintering Control of Copper Nanoparticles.

Flexible micro/nano metal grid transparent conductors emerged as an alternative to the fragile/rigid indium tin oxide electrode. They are usually fabricated by the combination of the conventional photolithography and the vacuum deposition of regular metal grid patterns, however, seriously suffer from moiré and starburst problems induced by periodic regular pattern structures. In this paper, we demonstrated flexible and imperceptible random copper microconductors with an extremely high figure-of-merit (∼2000) by the thermal conduction layer-assisted photonic sintering of copper nanoparticles without damages in the plastic substrate. This process can be easily applied to complicated structures and surfaces including a random pattern which is imperceptible and free of interferences. As a proof-of-concept, a transparent windshield defogger in a car was demonstrated with a Cu transparent random conductor at an extreme and reversible fogging state.

Manual, In situ, Real-Time Nanofabrication using Cracking through Indentation.

Nanofabrication has seen an increasing demand for applications in many fields of science and technology, but its production still requires relatively difficult, time-consuming, and expensive processes. Here we report a simple but very effective one dimensional (1D) nano-patterning technology that suggests a new nanofabrication method. This new technique involves the control of naturally propagating cracks initiated through simple, manually generated indentation, obviating the necessity of complicated equipment and elaborate experimental environments such as those that employ clean rooms, high vacuums, and the fastidious maintenance of processing temperatures. The channel fabricated with this technique can be as narrow as 10 nm with unlimited length and very high cross-sectional aspect ratio, an accomplishment difficult even for a state-of-the-art technology such as e-beam lithography. More interestingly, the fabrication speed can be controlled and achieved to as little as several hundred micrometers per second. Along with the simplicity and real-time fabrication capability of the technique, this tunable fabrication speed makes the method introduced here the authentic nanofabrication for in situ experiments.

Control and Manipulation of Nano Cracks Mimicking Optical Wave.

Generally, a fracture is considered as an uncontrollable thus useless phenomenon due to its highly random nature. The aim of this study is to investigate highly ordered cracks such as oscillatory cracks and to manipulate via elaborate control of mechanical properties of the cracking medium including thickness, geometry, and elastic mismatch. Specific thin film with micro-sized notches was fabricated on a silicon based substrate in order to controllably generate self-propagating cracks in large area. Interestingly, various nano-cracks behaved similar to optical wave including refraction, total internal reflection and evanescent wave. This novel phenomena of controlled cracking was used to fabricate sophisticated nano/micro patterns in large area which cannot be obtained even with conventional nanofabrication methods. We also have showed that the cracks are directly implementable into a nano/micro-channel application since the cracks naturally have a form of channel-like shape.

Highly stretchable and transparent metal nanowire heater for wearable electronics applications.

A highly stretchable and transparent electrical heater is demonstrated by constructing a partially embedded silver nanowire percolative network on an elastic substrate. The stretchable network heater is applied on human wrists under real-time strain, bending, and twisting, and has potential for lightweight, biocompatible, and versatile wearable applications.