Organic semiconductors such as acenes, oligothiophenes and rubrene have the potential to challenge silicon based semiconductors.  However, good phase purity is required and the control of polymorphism (where the same chemical compound exhibits two or more crystalline modifications) is crucial.

In their CrystEngComm Highlight, Aldo Brillante and colleagues from the universities of Bologna and Parma reveal how lattice phonon Raman microscopy is a powerful and efficient tool for in-situ characterisation of phase purity.  Raman microscopy works in the region of lattice phonons, which represent the fingerprint of a crystal lattice.  The technique can provide important information in crystal domains smaller than 1 micrometer.  Applications to both single crystals and thin films of organic semiconductors are considered.

Lattice phonon Raman microscopy can also be combined with theoretical studies to provide a unique body of information on crystal structure recognition of molecular crystals.

This Highlight is featured on the outside cover of CrystEngComm, issue 8, which illustrates monitoring crystal structures and phase purity by Lattice Phonon Raman microscopy