Research On Preparation Of Metal Grid Transparent Electrode By Laser Localization Removal

The metal grid transparent electrode has been widely used in touch screen,solar cell,liquid crystal display,organic light-emitting diode?OLED?and other devices owing to its advantages of good electrical conductivity,high optical transmittance,good flexibility,easy access of raw materials,etc.With the increasing demand for metal grid transparent electrodes with better photoelectric properties,the preparation methods have been continuously upgraded and innovated.However,the existing methods for preparing the metal grid transparent electrode always have some problems more or less.There are few reports on the study of using laser localization removal to prepare the metal grid transparent electrode with adjustable shape.Based on this,this paper presents the preparation of the metal grid transparent electrode by laser localization removal?selective laser ablation?.The effects of related laser parameters and grid array parameters on the preparation and performance of the metal grid transparent electrode were studied,and some significant results were obtained.1.Ag films were deposited on glass substrates by radio frequency?RF?magnetron sputtering and then ablated by a 532 nm nanosecond pulsed laser.The effects of laser fluence and defocusing amount on width and depth of laser-ablated grooves on100-nm-thick Ag films and the effects of scanning times on width and depth of laser-ablated grooves on 600-nm-thick Ag films were systematically studied respectively under single-and multi-scan laser ablation.Meanwhile,the mechanism of laser ablation was also investigated.It was found that according to the difference of laser energy per unit area irradiated on the surface of the Ag film,removal mechanisms could be mainly divided into the laser-induced thermal elastic force and vaporization of the thin film materials.Metal films would be detached from the substrate by the laser-induced thermal elastic force in the way of shearing along the weakly bonded grain boundary regions.And the vaporization of the metal film was realized by increasing the lattice temperature through electron-electron or electron-phonon scattering to over the melting point.It was also found that by adopting combinations of laser fluences from 0.1 to 1.8 J/cm² and defocusing amounts from 0 to 2.0mm during single-scan laser ablation,grooves with widths ranged from 53 to 196?m and depths ranged from 56 to 196 nm could be obtained.Under the combination of a constant laser fluence of 0.8 J/cm² and defocusing amount of 1.0 mm,the width of multi-scan laser-ablated grooves did not change significantly,and the depth increased linearly with increasing scanning number.The removal of Ag films with bigger thicknesses could be realized by further increasing the scanning numbers.2.Laser ablation of 100-nm-thick Ag films,which were deposited on glass substrates by radio frequency?RF?magnetron sputtering,was performed by using a 532 nm nanosecond pulsed laser.The effects of laser scanning speed,hatch distance and scanning method on edge quality of the laser-ablated grooves or patterns were systematically studied.Results indicated that when the laser scanning speed was 15 mm/s,the hatch distance was less than 90?m,and the scanning method was frame-typed serial scanning?FTSS?or frame-line combined scanning?FLCS?,clean and smooth edges without obvious heat-affected zone and Ag residues could be formed under the combination of a constant laser fluence of 0.8 J/cm² and defocusing amount of 1.0 mm.Compared with the pattern obtained by the traditional line-typed cyclic scanning?LTCS?method,the transmittances of the patterns obtained by FTSS and FLCS was higher.3.Ag grid transparent electrodes were prepared by laser localization removal in the way of selective laser ablation of Ag film on the glass substrates.The effects of grid height,grid pitch,grid line width and scanning method on morphology and photoelectric properties of the Ag grid transparent electrodes were studied.The experimental results suggested that when the grid height was 800 nm,grid pitch was 1.0 mm,grid line width was 90?m and scanning method was FLCS,the obtained Ag grid transparent electrode had the optimal overall photoelectric properties with an average optical transmittance?380⁷80 nm?of80.52%,a sheet resistance of 0.88?/sq and a figure of merit of 13.02×10^–2?^–1.