Semiconductivity and gas-sensing properties of crown-ether-substituted lutetium bisphthalocyanines

✍ Scribed by Pierre Bassoul; Thierry Toupance; Jacques Simon

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 208 KB
• Volume: 26
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(94)01576-4

✦ Synopsis

The conductivity of thin films of crown ether ( 15 -crown-5, 18 -crown-6) substituted lutetium bisphthalocyanines has been studied in the presence of various gases. Under vacuum the films show intrinsic semiconducting propertics (\left(\sigma \approx 10^{-6} \Omega^{-1}\right.) (\left.\mathrm{cm}^{-1}\right)). When exposed to an oxidant (\left(\mathrm{O}{2}, \mathrm{I}{2}, \mathrm{Br}_{2}\right)), the molecular semiconductors are progressively transformed into doped insulators (\left(\sigma \approx 10^{-9} \Omega^{-1} \mathrm{~cm}^{-1}\right)). Exposure to wet nitrogen yields fully reversible conductivity changes: a two orders of magnitude difference in conductivity is measured on oxidized films when the relative humidity varies from (10 %) to (90 %).