Pavel Stuzhin
Ivanovo State University of Chemistry & Technology
Professor Pavel Stuzhin is Head of the Organic Chemistry Department of the Ivanovo State University of Chemistry and Technology (Russia). He received his PhD in 1985 in organic and physical chemistry with prof. B.D.Berezin and has faculty positions at ISUCT since 1986. After research stay by professors L.Latos-Grazinski (Wroclaw), H.Homborg (Kiel), C.Ercolani (Rome) he became Full Professor in 2004. He is Deputy Editor of "Macroheterocycles" and coorganiser of "Porphyrazine" simposia at ICPP meetings. His research interests involve azaporphyrins, porphyrazines and heterocyclic phthalocyanine analogues. He is coauthor of 4 chapters in monorgaphs, 10 review articles, 2 patents and >120 experimental papers.
We have synthesized a series of small molecules-subporphyrinoids demonstrating high potential as alternative to fullerene for use in the organic solar cells. Chemical functionalization of subphthalocyanine molecule through adding halogens on the periphery is an effective strategy to obtain non-fullerene acceptors for the molecular or hybrid junctions [1]. Alternatively, we have modified the subporpyrazine core by annulation of electron-deficient 1,2,5-thiadiazole rings, so that the lightweight, air-stable and optically active molecules with strongly electron accepting properties are obtained [2]. Their chemical structures and the positions of molecular orbitals were elucidated both theoretically and experimentally [3].
The prototype thin-film photovoltaic cells with a fully subporphyrinoid planar heterojunction were fabricated, in which unsubstituted subphthalocyanine serves as a donor, and acceptor was its low-symmetry analog, 1,2,5-thiadiazole subporphyrazine [2,3]. Thickness and material of the interfacial layers were carefully optimized to enhance the charge transport in the device. J-V characteristics of thus made devices in the dark and under 1 sun illumination were measured in laboratory conditions; the EQE spectra were compared with the absorption spectra of the photoabsorber pairs in the range of 380-1000 nm.
It was found that the output parameters of the prototype cells vary largely with the chemical structure of subporphyrazine molecule and with the nature of adjacent cathode underlayer, which is a critical issue for the electron extraction. While the open circuit voltage lies in the range of 0.7-1.2 V, the short circuit current differs by orders of magnitude. The best performing devices employ a low symmetry subporphyrazine, their power conversion efficiency exceeds that of equivalent cells with a fullerene acceptor, considering that narrower spectral domain is utilized. The next steps to enhance the photon capturing capability and to increase the stability of the obtained small molecule based devices are discussed.
Acknowledgement is expressed to Russian Science Foundation (#17-13-01522).
[1] Cnops K., Zango G., Genoe J., Heremans P., Martinez-Diaz M.V., Torres T., Cheyns D. J.Am.Chem.Soc. 137 (2015) 8991.
[2] Hamdoush M., Skvortsov I.A., Mikhailov M.S., Pakhomov G.L., Stuzhin P.A., J. Fluorine Chem. 204 (2017) 31.
[3] Pakhomov G.L., Travkin V., Hamdoush M., Zhabanov Y.A, Stuzhin P.A., Macroheterocycles 10 (2017) 548; DOI:10.6060/mhc171038s.
