Fig. 4From: Facile Synthesis of Ultralong and Thin Copper Nanowires and Its Application to High-Performance Flexible Transparent Conductive ElectrodesSEM images of samples at different reaction time of hydrothermal treatment. The different reaction time of hydrothermal treatment are a 1 h, b 2 h, c 6 h, d 14 h, e 20 h, and f 40 hBack to article page