Non-Iridescent Metal Nanomesh with Disordered Nanoapertures Fabricated by Phase Separation Lithography of Polymer Blend as Transparent Conductive Film.

Xinyu Chen,Haixiong Ge,Chunyu Huang,Changsheng Yuan,Yang Li,Xiaofeng Chen,Yuting He,Yushuang Cui

doi:10.3390/ma14040867

Xinyu Chen, Haixiong Ge + Show 6 more

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https://doi.org/10.3390/ma14040867

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Abstract

Metallic nanomesh, one of the emerging transparent conductive film (TCF) materials with both high electrical conductivity and optical transmittance, shows great potential to replace indium tin oxide (ITO) in optoelectronic devices. However, lithography-fabricated metallic nanomeshes suffer from an iridescence problem caused by the optical diffraction of periodic nanostructures, which has negative effects on display performance. In this work, we propose a novel approach to fabricate large-scale metallic nanomesh as TCFs on flexible polyethylene terephthalate (PET) sheets by maskless phase separation lithography of polymer blends in a low-cost and facile process. Polystyrene (PS)/polyphenylsilsequioxane (PPSQ) polymer blend was chosen as resist material for phase separation lithography due to their different etching selectivity under O2 reactive ion etching (RIE). The PS constituent was selectively removed by O2 RIE and the remained PPSQ nanopillars with varying sizes in random distribution were used as masks for further pattern transfer and metal deposition process. Gold (Au) nanomeshes with adjustable nanostructures were achieved after the lift-off step. Au nanomesh exhibited good optoelectronic properties (RS = 41 Ω/sq, T = 71.9%) and non-iridescence, without angle dependence owing to the aperiodic structures of disordered apertures. The results indicate that this Au nanomesh has high potential application in high-performance and broad-viewing-angle optoelectronic devices.

Highlights

transparent conductive film (TCF) have driven intense research efforts because they serve as essential components for numerous optoelectronic devices like solar cells [1,2,3], and various display-related applications including touch panels [4,5,6], organic light-emitting diodes (OLEDs) [7,8,9], and flexible displays [10,11], all of which are in much demand [12]
We developed a new maskless lithographic approach, phase separation lithography based on polymer blends [29,30]
We demonstrate a transparent, conductive, flexible and durable metallic nanomesh film with amorphous nanoapertures made by phase separation of PS/ PPSQ polymer blend

Summary

Introduction

ITO, which has been developed for more than fifty years, still dominates the field today because of its high optoelectronic performance. ITO suffers from several drawbacks such as its scarcity of supply, high cost, brittleness, chemical instability and low conductivity [4,12]. These disadvantages certainly limit its applications in flexible and durable optoelectronic devices. It is highly desirable to develop alternatives with both high electrical conductivity and optical transmittance to traditional ITO. Mechanical flexibility, durability, ease of processing, and large-scale fabrication feasibility are expected in the generation of optoelectronic devices

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