Nano Focus: IR vibrational crystallography visualizes molecular orientation on the nanoscale

摘要： The orientation of molecules is of central importance in determining the photophysical properties of organic materials, such as mobility of charge carriers and ions. These orientation-dependent properties of materials further control their functionalities in biological systems and electronic devices, including organic light-emitting diodes and solar cells. Until now, optical crystallography has failed to yield high-resolution images of molecular arrangement, due to the diffraction-limited response, weak photon–material interaction between x-rays and organic materials, or sample damage. A group of researchers from the University of Colorado Boulder and Lawrence Berkeley National Laboratory has developed a new mapping technique called infrared scattering-type scanning near-field optical microscopy (IR s-SNOM), which can identify the molecular arrangement of subdomains smaller than hundreds of nanometers.