Polar intramolecular salts N-(indan-1,3 dion-2-yl) pyridinium betaine derivatives. Their electronic properties

Optical and electrical properties of oriented thin films of oligomer containing betaine‐type moiety in side chain

“…In addition, the maximum at wavelengths above >500 nm in poled samples is observed. Earlier studies confirm that IPB crystals and evaporated thin films may be regarded as excellent photoconductors [1]. The maximum of photoconductivity quantum efficiency β(hν) of vacuum-evaporated IPB thin films is observed at wavelengths above >500 nm (see from the spectra of ∆U S (hν) of both un-poled and poled IPB oligomer films and the β(hν) of a vacuumevaporated IPB film that an additional process of transport of photogenerated charge carriers of the IPB group may influence the value of the surface potential at longer wavelengths.…”

“…In the case of un-poled samples the maximum of ∆U S (hν) at this wavelength was absent. The betaine molecules (IPB) are known to undergo a reversible optically induced change of the value and sign of the dipole moment in the spectral region of PIET [1][2][3]. Consequently, it may be assumed that changes of the surface potential close to PIET spectral region is caused by photoinduced changes of dipole moment.…”

Photoinduced phenomena in corona poled polar organic films

“…To modify the dipole moment and also to optimize the properties of film formation as well as the photo oxidation in the film a number of IPB derivatives were synthesized at the Riga Technical University [10,12,13]. The studies of IPB and its derivatives-N-(5-nitroindan-1,3-dion-2-yl)pyridinium betaine (compound IPB-1) and N-[4V-(5-tert-butylindan-1,3-dion-2-yl)phenyl]-(2,4,6-triphenyl)pyridinium betaine (compound IPB-2) are reported (see Fig.…”

“…The absorption band of electron transfer from the indandione anion to the pyridinium betaine cation (PIET) is located around 380 nm. As a result of the transfer, the dipole moment of the molecule changes its sign and value to l e = À 5.1 D [10,11]. The difference between values of dipole moments in ground and excited states is ca.…”

“…2) being investigated since the 1970s [12] belongs to series of highly polar, photoactive intramolecular salts. The IPB and its derivatives are good photoconductors [10].…”