Nanoscale visualization of microcrystalline chlorophyll a investigated with scanning tunneling microscopy

We have studied the topography of microcrystalline chlorophyll a films, that have been electrodeposited onto gold electrodes, using scanning tunneling microscopy (STM). The STM revealed that the films possess a polycrystalline structure with small grain sizes of 50 to 100 nm in diameter and a very rough surface topography with a surface roughness of 5 to 10 nm over surface areas of 1 × 1 μm. The surface structure correlates with results from an earlier photocurrent study of microcrystalline chlorophyll a.