Laser filament growth sintering for multi-planar 1 μm printing with 80 μm vertical tolerance and its application to ultra-transparent dehumidifying glasses.

Herein, a rapid, eco-friendly, digital printing method is proposed for directly interconnecting individual electronics formed on the front and back planes of glass substrates, across the boundary edge, to obtain bezel-and soldering-free monolithic electronics. Laser filament scanning sintering, which is characterized by rapid scanning with a long and narrow laser spot with an aspect ratio of 500, allows for the selective formation of the electrode along the glass edge without pattern fluctuation. In this study, a novel dual-mode concurrent sintering interaction using a NIR laser filament beam, whereby nanoparticle sintering begins from the outer surface and the interface with the substrate, facilitates the device fabrication with high-resolution electrodes of 10 μm width on very rough and steeply curved edge surfaces at an ultrahigh speed of 3 m/s. This outstanding performance is accomplished by the combination of the effect of mild surface absorption of the NIR laser by a layer of Ag nanoparticles (1st mode) and intensive near-field surface scattering of the transmitting laser light (2nd mode). To intuitively demonstrate the feasibility of sustainable manufacturing of monolithic electronics, we successfully fabricated a workable bezel-and soldering-free LED panel, energy-supplied by a battery mounted on the rear plane, without the use of additional interconnection components.

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We report a novel one-step bottom-up fabrication method for multiscale-structured black Si, which is characterized by randomly distributed microscale Si layers covered with sub-100 nm protrusions with submicron boundary grooves. The unique multiscale structure, suggested as a “nanocanyon,” effectively minimizes light reflection over a broad spectrum by diversifying the scattering routes from the nanotextured surface to the wide distributed boundary micronanoscale grooves. This structure was achieved by hydrophobic clustering and local aggregation of instantaneously melted Si nanocrystals on a glass substrate under laser irradiation. This method can replace the complicated conventional silicon processes, such as patterning for selective Si formation, texturing for improved absorption, and doping for modifying the electrical properties, because the proposed method obviates the need for photolithography, chemical etching, vacuum processes, and expensive wafers. Finally, black Si photosensor arrays were successfully demonstrated by a low-cost solution process and a laser growth sintering technique for microchannel fabrication. The results show the great potential of the proposed fabrication method for low-cost and sustainable production of highly sensitive optoelectronics and as an alternative to conventional wafer-based photosensor manufacturing techniques.