Conductivity Measurements. Conductivity measurements were performed in air at room temperature using a HP3478A digital voltmeter, with a direct 4-wire resistance capability. TEM Measurements. For TEM measurements, samples were deposited as 10 μL of 1 mM of samples in ethanol solution on a copper support grid. TEM analysis was performed using a JEOL JEM-ARM200CFEG UHR microscope with a spherical aberration-corrected probe and equipped with a Gatan UltraScan camera model 994 US1000X.