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Next-generation stretchable optoelectronics require functional electric conductors with mechanical stretchability and optical transparency. We present a new class of highly stretchable and transparent conductors based on silver nanowire (AgNW) percolation microgrids embedded in an elastomeric substrate. These are prepared by simple spray-coating and subsequent adhesive-tape-assisted contact-removal of the AgNWs. The synergetic combination of the percolated NWs and regular micro-grid geometry in an integrated form makes it possible to achieve uniform, reproducible, and predictable performance of the resulting AgNW microgrids and ensure good stretchability. The fabricated device shows superior optoelectronic performance with a sheet resistance of 26.1 Ω/sq and an optical transmittance of 85.8 %. In addition, the device can reversibly accommodate various mechanical deformations, such as stretching, bending, and twisting. Graphical AbstractA new class of highly stretchable and transparent conductor based on silver nanowire (AgNW) percolation micro-grids prepared by spray-coating and subsequent adhesive-tape-assisted contact removal of AgNWs is presented.

Optical-resolution photoacoustic microscopy (OR-PAM), which has been widely used and studied as a noninvasive and in vivo imaging technique, can yield high-resolution and absorption contrast images. Recently, metallic nanoparticles and dyes, such as gold nanoparticles, methylene blue, and indocyanine green, have been used as contrast agents of OR-PAM. This study demonstrates real-time functional OR-PAM images with high-speed alternating illumination at 2 wavelengths. To generate 2 wavelengths, second harmonic generation at 532 nm with an LBO crystal and a pump wavelength of 1064 nm is applied at a pulse repetition rate of 300 kHz. For alternating illumination, an electro-optical modulator is used as an optical switch. Therefore, the A-line rate for the functional image is 150 kHz, which is half of the laser repetition rate. To enable fast signal processing and real-time displays, parallel signal processing using a graphics processing unit (GPU) is performed. OR-PAM images of the distribution of blood vessels and gold nanorods in a BALB/c-nude mouse's ear can be simultaneously obtained with 500 × 500 pixels and real-time display at 0.49 fps.