Lattice-phonon confocal Raman mapping is a powerful technique to probe the crystal structure of polymorphs of organic semiconductors. This technique is fast, reliable, and capable of monitoring physical modifications and phase inhomogeneities in crystal domains at the micrometer scale. Applying the technique to pentacene crystals (see Figure) shows that phase inhomogeneities are not confined to the crystal surface, but penetrate into the crystal.
Characterization of phase purity in organic semiconductors by lattice-phonon confocal Raman mapping: Application to pentacene / A. BRILLANTE; I. BILOTTI; R. G. DELLA VALLE; E. VENUTI; M. MASINO; A. GIRLANDO. - In: ADVANCED MATERIALS. - ISSN 0935-9648. - 17(2005), pp. 2549-2553. [10.1002/adma.200501350]