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Highly Thermostable, Non‐oxidizable Indium, Gallium, and Aluminium Perfluorophthalocyanines with n‐Type Character
Author(s) -
Łapok Łukasz,
Obłoza Magdalena,
Nowakowska Maria
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201601386
Subject(s) - homo/lumo , cyclic voltammetry , differential pulse voltammetry , gallium , thermal decomposition , chemistry , thermal stability , thermogravimetric analysis , indium , photochemistry , materials science , analytical chemistry (journal) , inorganic chemistry , organic chemistry , molecule , electrochemistry , electrode
Perfluorophthalocyanines incorporating three‐valent metals, namely In(Cl), Ga(Cl), and Al(Cl), have been synthesized and characterized. Thermogravimetric analysis revealed that these compounds exhibit outstanding thermal stability and a tendency to sublime at a temperature exceeding around 350 °C without thermal decomposition. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to probe the frontier orbital energy levels of these compounds in THF solution. All three compounds undergo three quasi‐reversible reductions with the first one leading to the formation of an anion radical, namely MPc −. , as confirmed by spectroelectrochemistry. The compounds studied were intrinsically resistive to oxidation, which indicates that they are very good electron acceptors (n‐type materials). The HOMO–LUMO energy gaps ( E g ) of the three compounds determined by UV/Vis spectroscopy were relatively unaffected by the three‐valent metals incorporated into the phthalocyanine macrocycle. Similarly, the energies of the HOMO ( E HOMO ) and LUMO ( E LUMO ) orbitals remained virtually unaffected by the three‐valent metals in the perfluorophthalocyanine. Importantly, all the perfluorophthalocyanines studied possess LUMO levels between −4.76 and −4.85 eV, which makes their reduced forms resistant to electron trapping by O 2 and H 2 O. This property opens up the possibility for the fabrication of electronic devices operating under ambient conditions. All three compounds demonstrated very good photostability as solid thin films.