Molecular Semiconductors in Organic Photovoltaic Cells

Organic photoresponse materials and devices are critically important to organic optoelectronics and energy crises. The activities of photoresponse in organic materials can be summarized in three effects, photoconductive, photovoltaic and optical memory effects. Correspondingly, devices based on the three effects can be divided into (i) photoconductive devices such as photodetectors, photoreceptors, photoswitches and phototransistors, (ii) photovoltaic devices such as organic solar cells, and (iii) optical data storage devices. It is expected that this systematic analysis of photoresponse materials and devices could be a guide for the better understanding of structure–property relationships of organic materials and provide key clues for the fabrication of high performance organic optoelectronic devices, the integration of them in circuits and the application of them in renewable green energy strategies (critical review, 452 references).

Organic photoresponse materials and devices

7.1. Synthesis 306 7.2. Spectroscopic and Redox Properties 307 7.2.1. Optical Spectroscopy 307 7.2.2. Redox Properties 310 7.2.3. Other Characterization Methods 312 8. seco-Porphyrazines 312 8.1. Synthesis 312 8.2. Spectroscopic and Redox Properties 312 8.2.1. Optical Spectroscopy 312 8.2.2. Redox Properties 313 8.2.3. Other Characterization Methods 313 9. Conclusions 313 10. Abbreviations 314 11. Acknowledgments 314 12. References 314

Low Symmetry Phthalocyanines and Their Analogues

Synthetic pathways to water-soluble phthalocyanines and close analogs

Cobalt phthalocyanine (CoPc) is a known electrocatalyst for the carbon dioxide reduction reaction (CO2RR) that, when adsorbed onto edge-plane graphite (EPG) electrodes, shows modest activity and selectivity for CO production along with co-generation of H2. In contrast, electrodes modified with CoPc immobilized in a poly-4-vinylpridine (P4VP) film show dramatically enhanced activity and selectivity compared to those modified with CoPc alone. CoPc-P4VP films display a faradaic efficiency of ∼90% for CO, with a turnover frequency of 4.8 s−1 at just −0.75 V vs. RHE. Two properties of P4VP contribute to enhancing the activity of CoPc: (1) the ability of individual pyridine residues to coordinate to CoPc and (2) the high concentration of uncoordinated pyridine residues throughout the film which may enhance the catalytic activity of CoPc through secondary and other outer coordination sphere effects. Electrodes modified with polymer-free, five-coordinate CoPc(py) films (py = pyridine) and with CoPc catalysts immobilized in non-coordinating poly-2-vinylpyridine films were prepared to independently investigate the role that each property plays in enhancing CO2RR performance of CoPc-P4VP. These studies show that a synergistic relationship between the primary and outer coordination sphere effects is responsible for the enhanced catalytic activity of CoPc when embedded in the P4VP membrane.

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Polymer coordination promotes selective CO2 reduction by cobalt phthalocyanine

Synthesis and characterization of novel soluble octa-cationic phthalocyanines

Unsymmetrical phthalocyanines with alkynyl substituents

Electrocatalytic oxygen reduction and hydrogen evolution reactions on phthalocyanine modified electrodes: Electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric monitoring

Cyclic voltammetry of octakis(hydroxyethylthio)-substituted phthalocyanines with 2H (H2OHETPc), Zn(II) (ZnIIOHETPc(−2)) and Co(II) (CoII(OHETPc(−2)) in the phthalocyanine core has been investigated in dimethylsulfoxide (DMSO), and some of the results were evaluated together with their absorption spectra in the visible range. The redox processes due to both aggregated and non-aggregated species were observed on the voltammograms of phthalocyanines with Zn(II). The effect of chloride ion on the cyclic voltammetry of CoIIOHETPc(−2) has been investigated in the DMSO/ClO4− couple. The comparison of cyclic voltammetry for CoIIOHETPc in the absence and presence of chloride ion showed that chloride ion does not bind to either Co(II) or Co(I) but does bind very strongly to Co(III). The detailed electrochemistry of CoIIOHETPc(−2) was investigated in terms of the Co(I)/Co(II) and Co(II)/Co(III) redox couples, and various equilibria related to the species coordinated to Co(II) and Co(III) in the phthalocyanine core.

Zehra Altuntaş Bayır

Papers

Synthesis and characterization of novel soluble octa-cationic phthalocyanines

Unsymmetrical phthalocyanines with alkynyl substituents

Electrocatalytic oxygen reduction and hydrogen evolution reactions on phthalocyanine modified electrodes: Electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric monitoring

Electrochemical properties of octakis(hydroxyethylthio)‐substituted phthalocyanines

Synthesis of phthalocyanines with tridentate branched bulky and alkylthio groups