Editing Pyrene (section)

==Applications==
{{multiple image
| align = left
| direction = vertical
| width = 180
| image1 = Br4Py self-assembly on Au.jpg
| caption1 = 
| image2 = Br4Py self-assembly on Au 2.jpg
| caption2 = [[Scanning tunneling microscopy|STM]] image of self-assembled Br<sub>4</sub>Py molecules on Au(111) surface (top) and its model (bottom; pink spheres are Br atoms).<ref>{{cite journal|doi=10.1039/C4CC02753A |title=Self-assembly of pyrene derivatives on Au(111): Substituent effects on intermolecular interactions |journal=Chem. Commun. |volume=50 |issue=91 |pages=14089–92 |year=2014 |last1=Pham |first1=Tuan Anh |last2=Song |first2=Fei |last3=Nguyen |first3=Manh-Thuong |last4=Stöhr |first4=Meike |pmid=24905327 |doi-access=free }}</ref>
}}
Pyrene's fluorescence [[emission spectrum]] is very sensitive to solvent polarity, so pyrene has been used as a probe to determine solvent environments. This is due to its excited state having a different, non-planar structure than the ground state. Certain emission bands are unaffected, but others vary in intensity due to the strength of interaction with a solvent.[[File:Pyrene-numbering.svg|thumb|190px|Diagram showing the numbering and ring fusion locations of pyrene according to [[IUPAC nomenclature of organic chemistry]].]]

Pyrenes are strong electron donor materials and can be combined with several materials in order to make electron donor-acceptor systems which can be used in energy conversion and light harvesting applications.<ref name=":0" />