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Oxovanadium(IV) etioporphyrin‐III, VO‐EtioP‐III is an important member of the petroporphyrin family. It can be isolated from crude oil or synthesized de novo from the dipyrromethene precursors, the latter being the approach we used in our research. The molecular structure of VO‐EtioP‐III was for the first time characterized by single‐crystal X‐ray diffraction. Both terminal alkyls and the axial oxygen atom protrude in the same direction relative to the molecular plane, while rear side of the molecule remains almost flat. This results in a peculiar centrosymmetric packing (space group P21/c, monoclinic system with four molecules per unit cell), in which back‐to‐back oriented molecules form the parallel‐plane dimers. The powder X‐ray diffraction data indicate that the VO‐EtioP‐III films deposited by vacuum evaporation retain a very strong texture, with all molecules standing vertically on the substrate surface. The absorption spectra of films differ from the solution spectra by a large redshift of the Soret‐ and Q‐ band (~30 nm) with hypo‐ and hyperchromic effects, respectively. The former band strongly broadens due to multiple splitting to within 350–520 nm, which is followed by a change of the color from purple (in diluted solutions) to brawn (in films or crystals). [ABSTRACT FROM AUTHOR]

A new complex of indium(III)chloride with etioporphyrin‐I was synthesized and characterized. As with naturally occurring extraligated etioporphyrins, the InCl‐EtioP−I spectrum in solution has a very strong B‐band and a more than an order of magnitude weaker Q‐band, but this difference diminishes in solid films of InCl‐EtioP−I obtained by thermal evaporation in vacuum. In a solid, molecules have a tight convex‐convex arrangement in a 2D double layered structure with interplane distance of 3.066 Å. The conductivity of films can easily be activated by the action of temperature or light. In the cells with symmetrical lateral contacts the photocurrent exceeds the dark current by about three orders of magnitude, with the contribution of photons in the Q‐band range being greater than expected from the experimental or calculated absorption spectrum. The Q‐bands contribute significantly to the photovoltaic effect in the ITO/InCl‐EtioP−I/Al sandwich cells. Such cells show an untypically strong signal in the photodiode regime, which yields the spectral detectivity of 10^12 Jones. [ABSTRACT FROM AUTHOR]

Stable subphthalocyanine-type dyes with a high electron affinity attract much attention as potential substitutes for traditional fullerenes in molecular electronics devices. One possible way to enhance the acceptor properties of the subphthalocyanine core is by replacing the peripheral benzene fragments (C6H4) with 1,2,5-thiadiazole fragments (C2N2S1). However, the resistance of these materials to light or atmospheric effect remains an open question, which limits their further application in device manufacturing. In this work, we compare vacuum-deposited films of three derivatives, SubPzS3H0 (all peripheral fragments are 1,2,5-thiadiazoles), SubPzS2H4 (two fragments are 1,2,5-thiadiazoles and one fragment is benzene), and SubPcS0H12 (all benzenes, i.e., parent subphthalocyanine). Practically relevant substrates were used for deposition, namely, bare glass, glass/ITO or FTO, and PET/ITO. Photobleaching of films under continuous 1 sun illumination was studied in laboratory air, synthetic air, and ultrapure argon. It is shown that the exclusion of near-UV photons from the incident light spectrum, which corresponds to the absorption of subphthalocyanines in the Soret-band, strongly inhibits degradation. Absorption in the Q-band range initiates soft annealing rather than photobleaching of films. The stability of the films deposited on glass decreases as SubPzS3H0 > SubPzS2H4 > SubPcS0H12 in air, and vice versa in argon. The substrate adds more complexity to this picture. In argon, the ITO coating reduces degradation of all of the compounds equally, in contrast to the glass samples, while in air, the SubPzS3H0 films discolor completely. The latter reaction proceeds due to the indium-containing species migrating from the conductive coating. [ABSTRACT FROM AUTHOR]