(1) Single-layer organic photosensitizing dye electrode
Using methods such as vacuum deposition, spin coating and electrochemical deposition, organic dyes are modified on metal, conductive glass or semiconductor surfaces, and their optoelectronic properties are studied in electrolytes. Among different metalloporphyrin compounds, Zn and Mg as the central metals have the best optoelectronic properties. Different functional substituents, such as mono-, nitro, amino, carboxyl, methyl, etc., have obvious effects on the optoelectronic properties, indicating that the optoelectronic properties can be optimized by changing the types and positions of functional substituents. The optoelectronic properties of metal phthalocyanine compounds are also closely related to the central metal. CoPc, SnPc, PbPc, FePc, NiPc) have superior photoelectric properties.
This is because the spectral response of trivalent and tetravalent metal phthalocyanines is wider, and the chlorine and oxygen atoms in the molecule are favorable for electron transfer. The electrochemically polymerized film of copper such as phthalide has a larger conjugated system than the monomer, the electrons are easier to move and migrate, and the contact resistance between the electropolymerized film and the substrate is small, so it shows better performance than its monomer. Photoelectric properties. In addition to organic photosensitizing dyes, the photoelectric properties are also affected by the acid-base and redox properties of the electrolyte, as well as the oxidative and reducing atmospheres in the environment.
(2) Double-layer organic photosensitizing dye electrode
The maximum absorption wavelength of metalloporphyrin is around 410nm, the light absorption of wavelengths greater than 410nm is weak, and metallophthalocyanine has strong light absorption at the wavelength of 600~700nm. The combination of phenoline or tetratolyl porphyr and zinc phthalocyanine or aluminum phthalocyanine forms a double-layer structure electrode, which expands the response range of the absorption solar spectrum and produces an obvious photoelectric property addition effect.
Organic photosensitizing dyes with different semiconductor properties can form double-layer organic P-N junction electrodes, that is, organic solid-state heterojunction solar cells, such as organic heterojunction solar cells ITO composed of N-type North Red and P-type talop compounds. /MePTC/MPe/Ag (MePTC is a North Red derivative, MPc is InCIPc, VOPc, GaCIPc, TiOPc, H2Pc, ZnPc), its absorption covers visible light energy with a wavelength of 400~900nm (MePTC absorbs 400~600nm, MPe absorbs 600~900nm wavelength visible light), increase the photocurrent from a few microamperes of the single-layer dye current to several hundreds of microamperes, and the current filling factor and photoelectric conversion efficiency are also significantly improved. c carried out energy transfer, and various MP c formed structures with different molecular arrangements in the vacuum coating, which had an effect on exciton migration, and thus exhibited different optoelectronic properties. Further doping with VOP c in the In CIP c film improves the crystal state of the In CIP c solid film, which exhibits a synergistic behavior of photocurrent and fill factor. It shows that the doping of organic molecules is an effective way to improve the photoelectric conversion efficiency of organic solar cells.
(3) Ordered combination of organic photosensitizing dye molecules
Organic photo-dye (S) and electron donor (D) or acceptor molecule (A) bonded multiple photosensitive dipole molecules (S-D-A) are used as model compounds for simulating photosynthesis reaction centers. Recently, research is very active, such as cyanine It forms a charge transfer complex with the ballene molecule C60. Due to the accelerated intramolecular photosensitive electron transfer rate, the binary molecules of porphine, talpro and the electron acceptor allonone make the photocurrent and photovoltage larger than that of the unit dye molecule. In order to better simulate the high-efficiency light energy conversion of plant photosynthesis in a highly ordered system, a series of binary, ternary and quaternary photosensitive dipole molecules were designed and synthesized, such as porphyrin viologen (SA), porphyrin violet Purified carbazole (S-A-D), porphyrin-terephthalate viologen-yesterazole (S-A1-A2-D), Eurocyanine ferrocene (S-A-D), etc., the molecules are ordered by LB membrane technology Combined, the multi-dipole molecules with different structures are studied through a multi-step charge transfer process, which improves the charge separation efficiency, making their photocurrent and photovoltage in the order of quaternary molecule > ternary > binary > unit molecule.
Further optimization of molecular arrangement, spatial orientation and molecular spacing can extend the lifetime of the charge separation state to the microsecond level. This not only provides a lot of scientific information for the research of artificially simulated photosynthesis light energy conversion, but also designs and synthesizes a large number of multi-component photosensitive dipole molecules with stable performance and novel structure, which can provide a basis for the in-depth study of energy conversion of organic photosensitizing dye systems and the development of organic /Nano-semiconductor composite optoelectronic materials have laid a good foundation.
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