This article is cited in 1 paper

Dielectrics

Size effects in photoexcitation of triplet states of ammonium tetraphenylborate

V. A. Nadolinnyi^a, O. V. Antonova^a, E. A. Il'inchik^a, M. K. Kovalev^b, M. S. Mel'gunov^b, A. P. Eliseev^c, A. A. Ryadun<sup>a

a</sup> Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk
^b Boreskov Institute of Catalysis SB RAS, Novosibirsk
^c Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk

Abstract: This paper reports on the results of complex investigations of photoexcited states of ammonium tetraphenylborate, which are characterized by self-sensitized luminescence. It has been established that the excitation by UV light at 77 K leads to the formation of stable triplet states due to the capture of electrons on electron traps. The EPR and luminescence excitation spectra exhibit the formation of a set of triplet states with different distances between electrons and holes. The performed investigations give grounds to affirm that, in bulk samples, cations in the structure of ammonium tetraphenylborate are electron traps. When the size of the ammonium tetraphenylborate sample is changed to 6 and 3 nm, the capture of excited electrons on sorbed oxygen molecules becomes dominant. In this case, the appearance of the spectrum of O$_2^-$ anion radicals has been detected by the EPR method. The proposed interpretation of the observed effects has been confirmed by the thermoluminescence data on the recombination of electron-hole pairs, which correlate with a change in the intensity of the EPR spectra during annealing.

Received: 12.05.2010

 English version: Physics of the Solid State, 2011, 53:2, 284–291

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