Editing Pyrene (section)

===Photophysics===

Pyrene and its derivatives are used commercially to make [[dye]]s and dye precursors, for example [[pyranine]] and naphthalene-1,4,5,8-tetracarboxylic acid. It has strong absorbance in UV-Vis  in three sharp bands at 330&nbsp;nm in DCM. The emission is close to the absorption, but moving at 375&nbsp;nm.<ref name=":0">{{Cite journal|last1=Tagmatarchis|first1=Nikos|last2=Ewels|first2=Christopher P.|last3=Bittencourt|first3=Carla|last4=Arenal|first4=Raul|last5=Pelaez-Fernandez|first5=Mario|last6=Sayed-Ahmad-Baraza|first6=Yuman|last7=Canton-Vitoria|first7=Ruben|date=2017-06-05|title=Functionalization of MoS 2 with 1,2-dithiolanes: toward donor-acceptor nanohybrids for energy conversion|journal=npj 2D Materials and Applications|language=en|volume=1|issue=1|pages=13|doi=10.1038/s41699-017-0012-8|issn=2397-7132|doi-access=free|hdl=10261/367520|hdl-access=free}}</ref>  The morphology of the signals change with the solvent. Its derivatives are also valuable molecular probes via [[fluorescence]] spectroscopy, having a high quantum yield and lifetime (0.65 and 410 nanoseconds, respectively, in [[ethanol]] at 293&nbsp;K).  Pyrene was the first molecule for which [[excimer]] behavior was discovered.<ref>{{cite journal |last1=Van Dyke |first1=David A. |last2=Pryor |first2=Brian A. |last3=Smith |first3=Philip G. |last4=Topp |first4=Michael R. |title=Nanosecond Time-Resolved Fluorescence Spectroscopy in the Physical Chemistry Laboratory: Formation of the Pyrene Excimer in Solution |journal=Journal of Chemical Education |date=May 1998 |volume=75 |issue=5 |pages=615 |doi=10.1021/ed075p615|bibcode=1998JChEd..75..615V }}</ref> Such excimer appears around 450&nbsp;nm.  [[Theodor Förster]] reported this in 1954.<ref>{{cite journal |last1=Förster |first1=Th. |last2=Kasper |first2=K. |title=Ein Konzentrationsumschlag der Fluoreszenz. |journal=Zeitschrift für Physikalische Chemie |date=June 1954 |volume=1 |issue=5_6 |pages=275–277 |doi=10.1524/zpch.1954.1.5_6.275}}</ref>