Chandra Shakher Pathak

By Samir Kumar, Prabhat Kumar, Anamika Das and Chandra Shakher Pathak

Scattering of light by molecules can be elastic, Rayleigh scattering, or inelastic, Raman scattering. In the elastic scattering, the photon’s energy and the state of the molecule after the scattering events are unchanged. Hence, Rayleigh scattered light does not contain much information on the structure of molecular states. In inelastic scattering, the frequency of monochromatic light changes upon interaction with the vibrational states, or modes, of a molecule. With the advancement in the laser sources, better and compact spectrometers, detectors, and optics Raman spectroscopy have developed as a highly sensitive technique to probe structural details of a complex molecular structure. However, the low scattering cross section (10−31) of Raman scattering has limited the applications of the conventional Raman spectroscopy. With the discovery of surface-enhanced Raman scattering (SERS) in 1973 by Martin Fleischmann, the interest of the research community in Raman spectroscopy as an analytical method has been revived. This chapter aims to familiarize the readers with the basics of Raman scattering phenomenon and SERS. This chapter will also discuss the latest developments in the SERS and its applications in various fields.

Part of the book: Recent Advances in Nanophotonics

By Chandra Shakher Pathak

Atomic force microscopy (AFM) has become widely used technique in air, liquids, or vacuum to generate high-resolution topographic images of a surface having a nanometer-scale resolution. AFM gives the information about the morphology, phase composition etc. Photovoltaic materials have been attracting intense interest due to their performance and the morphology as well as quality of these materials affects their performance. AFM is now a day widely used technique for morphology and other electronic properties measurements at nanoscale for photovoltaic materials to understand their relation with device performance. This chapter describe the brief introduction of Kelvin probe force microscopy (KPFM) and conducting atomic force microscopy (CAFM) and their application in electrical characterization at nanoscale of organic and perovskite photovoltaic materials.

Part of the book: Recent Developments in Atomic Force Microscopy and Raman Spectroscopy for Materials Characterization