Synthesis and spectroscopic properties of a novel perylenediimide derivative

A novel symmetric 3,4,9,10-perylenetetracarboxylic acid derivative (PDI1) dye based on thiophene donor group was synthesized and characterized by FT-IR and 1H NMR. Cyclic Voltammetry analysis is performed to determine the energy levels of the perylene derivative. Optical characteristics were determined by visible absorption and fluorescence emission spectra. Spectral behavior and fluorescence quantum yield of PDI1 have been measured in different solvents. The dye exhibits high fluorescence quantum yield ( Φf: 0.94-0.99). But the quantum yield PDI1 is very low in the n-butanol solution ( Φf: 0.12). The photophysical properties have important implications for use in a variety of electroactive and photovoltaic applications. A photovoltaic device was fabricated with PDI1 as transporting material. The conversion efficiency for DSSC sensitized by PDI1 is 0.0065%. PDI1 exhibits electrochromic behavior by switching between neutral (red) and oxidized (blue) states. Electron transfer capacity of PDI to the TiO2 was investigated by incorporation of dye as sensitizer in dye sensitized solar cell (DSSC). Soluble dye molecules are very important to prepare dye sensitized solar cell. Solubility was increased with thiophene group

Fingerprints for Structural Defects in Poly(thienylene vinylene) (PTV): A Joint Theoretical–Experimental NMR Study on Model Molecules

In the field of plastic electronics, low band gap conjugated polymers like poly(thienylene vinylene) (PTV) and its derivatives are a promising class of materials that can be obtained with high molecular weight via the so-called dithiocarbamate precursor route. We have performed a joint experimental- theoretical study of the full NMR chemical shift assignment in a series of thiophene-based model compounds, which aims at (i) benchmarking the quantum-chemical calculations against experiments, (ii) identifying the signature of possible structural defects that can appear during the polymerization of PTV's, namely head-to-head and tail-to-tail defects, and (iii) defining a criterion regarding regioregularity

Optical and EPR spectroscopy in pure and blended films of a novel low band gap polymer

Efficient charge transfer between a newly synthesized low band gap (LBG) conjugated polymer and the C60 derivative PCBM is demonstrated. Spectral and time-resolved photoluminescence (PL) measurements show strong quenching and charge separation in the picosecond time range. The charge transfer is further confirmed by light-induced electron paramagnetic resonance (EPR) measurements of both the positive polarons and the fullerene radicals, which can be resolved in high-frequency EPR. The potential for the LBG polymer to act as acceptor was examined in blends with the para-phenylene-vinylene polymer MDMO-PPV. No charge transfer, but instead energy transfer from MDMO-PPV to LBG occurs in these blends, as shown by PL spectroscopy

Side chain effects on photoinduced absorption and photovoltaic performance of low bandgap thienylene vinylene and phenylene vinylene copolymers

In this work low bandgap thienylenevinylene and phenylene vinylene copolymers, which possess either 3,4-ethylenedioxylthiophene (EDOT) groups (Polymer 1) or long alkyl side chains (Polymer 2) were investigated and compared in photoinduced electron transfer properties and photovoltaic performance. The results show that the interaction of the photoexcited polymers with an electron acceptor ([6,6]-phenyl C61 – butyric acid methyl ester (PCBM)) leads to charge generation and transfer for both polymers. We found that the long alkyl side chain in Polymer 2 instead of the EDOT group in Polymer 1 enhances the open circuit voltage ($V_{\it OC})$ but lowers the short circuit current ($I_{\it SC})$. On the other hand the long alkyl side chain in Polymer 2 significantly improves the solubility and enhances processability for solar cells fabrication. Optimization of the chemical structure of these low bandgap polymers could lead to a spectral improvement of photocurrent generation in organic solar cells