Dmytro Sydorov | Institute of bioorganic chemistry and Petrochemistry NAS Ukraine (original) (raw)
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Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine, Kyiv
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Papers by Dmytro Sydorov
Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in apr... more Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in apro-tic acetonitrile medium have been revisited to better understand their specificity in a wide range of potentials and applicability in a complementary RGB electrochromic device. We find that kinetic limitations of electrochemical reduction of the polymers cause some distortions in their electronic absorption spectra, which are registered at different potentials. These limitations are very substantial for PANI and result in keeping quinoid units in the electrochemically reduced PANI structure. The complete PANI electrochemical reduction to leucoemeraldine state is realized only after 15 min of electrochemical polarization at −500 mV (vs. Ag/Ag +). Based on step-by-step polarization and with simultaneous registration of UV–vis spectra of P3MT, we have revealed additional isosbestic point at 765 nm appearing above 400 mV (vs. Ag/Ag +), which corresponds to transition of P3MT from polaron state to bipolaron one. Based on additivity of the spectroelectrochemical behavior of the polymers, spectral characteristic of light source and CIE standards we modeled RGB color palette of the complementary electrochromic device (ECD) of transmissive type. This palette is similar to colors of the real ECD prototype, in which electrochemically synthesized P3MT and PANI are working as an ensemble of electrochromic active layers.
Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) a... more Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) and poly(3-methylthiophene) (P3MT) has been applied to form the photovoltaically active hybrid organic–inorganic heterostructure. Photoluminescence and photoconductivity characterization of the synthesized ZnO comp and ZnO NR layers display their different defect and doping states resulting in a non-linear I–V behavior of the assembled complex ZnO comp /ZnO NR layer structure for account of formation of a p–n junction at the interface. We find some healing of the defect states at surface of the ZnO comp layer after its covering with ZnO NR layer. The photoelectrochemical deposition of the stable P3MT on surface of the complex ZnO comp /ZnO NR structure is realized under light irradiation with wavelength close to near-band-edge (NBE) emission of ZnO (∼380 nm) when using the special mixed voltammetry–potentiostatic–galvanostatic mode. This mode is found to minimize overoxida-tion/degradation of the forming P3MT. After the synthesis the formed P3MT layer is electrochemically reduced to move it to a semiconductor state. The resulting hybrid ZnO comp /ZnO NR /P3MT heterostructure is photovoltaically active and displays open-circuit voltage about 0.45 V.
Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in apr... more Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in aprotic acetonitrile medium have been revisited to better understand their specificity in a wide range of potentials and applicability in a complementary RGB electrochromic device. We find that kinetic limitations of electrochemical reduction of the polymers cause some distortions in their electronic absorption spectra, which are registered at different potentials. These limitations are very substantial for PANI and result in keeping quinoid units in the electrochemically reduced PANI structure. The complete PANI electrochemical reduction to leucoemeraldine state is realized only after 15 min of electrochemical polarization at −500 mV (vs. Ag/Ag + ). Based on step-by-step polarization and with simultaneous registration of UV-vis spectra of P3MT, we have revealed additional isosbestic point at 765 nm appearing above 400 mV (vs. Ag/Ag + ), which corresponds to transition of P3MT from polaron state to bipolaron one. Based on additivity of the spectroelectrochemical behavior of the polymers, spectral characteristic of light source and CIE standards we modeled RGB color palette of the complementary electrochromic device (ECD) of transmissive type. This palette is similar to colors of the real ECD prototype, in which electrochemically synthesized P3MT and PANI are working as an ensemble of electrochromic active layers.
Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) a... more Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) and poly(3-methylthiophene) (P3MT) has been applied to form the photovoltaically active hybrid organic–inorganic heterostructure. Photoluminescence and photoconductivity characterization of the synthesized ZnO comp and ZnO NR layers display their different defect and doping states resulting in a non-linear I–V behavior of the assembled complex ZnO comp /ZnO NR layer structure for account of formation of a p–n junction at the interface. We find some healing of the defect states at surface of the ZnO comp layer after its covering with ZnO NR layer. The photoelectrochemical deposition of the stable P3MT on surface of the complex ZnO comp /ZnO NR structure is realized under light irradiation with wavelength close to near-band-edge (NBE) emission of ZnO (∼380 nm) when using the special mixed voltammetry–potentiostatic–galvanostatic mode. This mode is found to minimize overoxida-tion/degradation of the forming P3MT. After the synthesis the formed P3MT layer is electrochemically reduced to move it to a semiconductor state. The resulting hybrid ZnO comp /ZnO NR /P3MT heterostructure is photovoltaically active and displays open-circuit voltage about 0.45 V.
Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in apr... more Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in apro-tic acetonitrile medium have been revisited to better understand their specificity in a wide range of potentials and applicability in a complementary RGB electrochromic device. We find that kinetic limitations of electrochemical reduction of the polymers cause some distortions in their electronic absorption spectra, which are registered at different potentials. These limitations are very substantial for PANI and result in keeping quinoid units in the electrochemically reduced PANI structure. The complete PANI electrochemical reduction to leucoemeraldine state is realized only after 15 min of electrochemical polarization at −500 mV (vs. Ag/Ag +). Based on step-by-step polarization and with simultaneous registration of UV–vis spectra of P3MT, we have revealed additional isosbestic point at 765 nm appearing above 400 mV (vs. Ag/Ag +), which corresponds to transition of P3MT from polaron state to bipolaron one. Based on additivity of the spectroelectrochemical behavior of the polymers, spectral characteristic of light source and CIE standards we modeled RGB color palette of the complementary electrochromic device (ECD) of transmissive type. This palette is similar to colors of the real ECD prototype, in which electrochemically synthesized P3MT and PANI are working as an ensemble of electrochromic active layers.
Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) a... more Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) and poly(3-methylthiophene) (P3MT) has been applied to form the photovoltaically active hybrid organic–inorganic heterostructure. Photoluminescence and photoconductivity characterization of the synthesized ZnO comp and ZnO NR layers display their different defect and doping states resulting in a non-linear I–V behavior of the assembled complex ZnO comp /ZnO NR layer structure for account of formation of a p–n junction at the interface. We find some healing of the defect states at surface of the ZnO comp layer after its covering with ZnO NR layer. The photoelectrochemical deposition of the stable P3MT on surface of the complex ZnO comp /ZnO NR structure is realized under light irradiation with wavelength close to near-band-edge (NBE) emission of ZnO (∼380 nm) when using the special mixed voltammetry–potentiostatic–galvanostatic mode. This mode is found to minimize overoxida-tion/degradation of the forming P3MT. After the synthesis the formed P3MT layer is electrochemically reduced to move it to a semiconductor state. The resulting hybrid ZnO comp /ZnO NR /P3MT heterostructure is photovoltaically active and displays open-circuit voltage about 0.45 V.
Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in apr... more Spectroelectrochemical properties of poly(3-methylthiophene) (P3MT) and polyaniline (PANI) in aprotic acetonitrile medium have been revisited to better understand their specificity in a wide range of potentials and applicability in a complementary RGB electrochromic device. We find that kinetic limitations of electrochemical reduction of the polymers cause some distortions in their electronic absorption spectra, which are registered at different potentials. These limitations are very substantial for PANI and result in keeping quinoid units in the electrochemically reduced PANI structure. The complete PANI electrochemical reduction to leucoemeraldine state is realized only after 15 min of electrochemical polarization at −500 mV (vs. Ag/Ag + ). Based on step-by-step polarization and with simultaneous registration of UV-vis spectra of P3MT, we have revealed additional isosbestic point at 765 nm appearing above 400 mV (vs. Ag/Ag + ), which corresponds to transition of P3MT from polaron state to bipolaron one. Based on additivity of the spectroelectrochemical behavior of the polymers, spectral characteristic of light source and CIE standards we modeled RGB color palette of the complementary electrochromic device (ECD) of transmissive type. This palette is similar to colors of the real ECD prototype, in which electrochemically synthesized P3MT and PANI are working as an ensemble of electrochromic active layers.
Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) a... more Step by step electrochemical assembling layers of compact ZnO (ZnO comp), ZnO nanorods (ZnO NR) and poly(3-methylthiophene) (P3MT) has been applied to form the photovoltaically active hybrid organic–inorganic heterostructure. Photoluminescence and photoconductivity characterization of the synthesized ZnO comp and ZnO NR layers display their different defect and doping states resulting in a non-linear I–V behavior of the assembled complex ZnO comp /ZnO NR layer structure for account of formation of a p–n junction at the interface. We find some healing of the defect states at surface of the ZnO comp layer after its covering with ZnO NR layer. The photoelectrochemical deposition of the stable P3MT on surface of the complex ZnO comp /ZnO NR structure is realized under light irradiation with wavelength close to near-band-edge (NBE) emission of ZnO (∼380 nm) when using the special mixed voltammetry–potentiostatic–galvanostatic mode. This mode is found to minimize overoxida-tion/degradation of the forming P3MT. After the synthesis the formed P3MT layer is electrochemically reduced to move it to a semiconductor state. The resulting hybrid ZnO comp /ZnO NR /P3MT heterostructure is photovoltaically active and displays open-circuit voltage about 0.45 V.