Theoretical study on naphthobischalcogenadiazole conjugated polymer systems and C61 derivative as organic photovoltaic semiconductors

We investigated the charge-transfer reactions of solar cells including a quaterthiophene copolymer with naphtho-bis-thiadiazole (PNTz4T) and naphtho-bis-oxadiazole (PNOz4T) using constrained density functional theory (CDFT). According to our calculations, the high electron-transfer rate results in a highly efficient solar cell, and the stable charge-transfer state results in low energy loss. Our computations imply that the following three factors are crucial to improve the performance of semiconducting polymers: (i) large structural changes following charge-transfer, (ii) narrow band gap, and (iii) spatially delocalized lowest unoccupied molecular orbital (LUMO) of the ground state

Novel 1,8-Naphthalimide derivative with an open space for an anion: Unique fluorescence behaviour depending on the binding anion’s electrophilic property

We have designed a novel 1,8-naphthalimide derivative with an open space for an anion. Computational calculation has predicted that the space could trap various anion species and photo-induced charge transfer depending on the anion's electrophilic properties. Indeed, the fluorescence behaviour of the 1,8-naphthalimide derivative complexes with each anion is consistent with the computational prediction

Correlation between susceptibility to environment-assisted cracking of super-elastic TiNi alloy and the states and their amount of hydrogen in it

Susceptibility to environment-assisted cracking (EAC) of super-elastic TiNi alloy has been correlated with the states and their amount of hydrogen in the material. The TiNi alloy specimen was immersed in sulfate solutions at a given pH, and a giving cathodic potential was applied to it for 13 ks to absorb hydrogen into it. The specimen was subjected to X-ray diffraction (XRD) test to detect hydride, and to thermal gas desorption spectroscopy (TDS) test to determine the state and its amount of hydrogen in it. In the case that a potential of -0.5 VAg/AgCl was applied to the specimen in the solution of pH 3, the XRD detected no hydride on it. Whereas, application of -1.5 VAg/AgCl was induced formation of hydride. The TDS indicated that the specimen treated at -0.5 VAg/AgCl involved hydrogen desorbing around 810 K, and the one at -1.5 VAg/AgCl involved hydrogen desorbing around 500 as well as 810 K. Therefore, it was suggested that the hydrogen desorbing at lower and higher temperatures obtained by the TDS were of hydride state and solid-solution state, respectively. The specimens treated under various conditions were analyzed by the same way as mentioned before, and an amount of the hydrogen in each state as well as a cathodic charge density applied to the specimen were obtained to be correlated. A logarithm of the amount of the hydrogen in the each state increased almost linearly with an increase in a logarithm of a charge density. Susceptibility to the EAC of the material suddenly increased around a charge density of 0.025 MC·m-2, and the charge density was considered to induce the amounts of hydrogens in hydride and solid-solution state of 10 and 100 mass ppm, respectively

Correlation between susceptibility to environment-assisted cracking of super-elastic TiNi alloy and the states and their amount of hydrogen in it

Susceptibility to environment-assisted cracking (EAC) of super-elastic TiNi alloy has been correlated with the states and their amount of hydrogen in the material. The TiNi alloy specimen was immersed in sulfate solutions at a given pH, and a giving cathodic potential was applied to it for 13 ks to absorb hydrogen into it. The specimen was subjected to X-ray diffraction (XRD) test to detect hydride, and to thermal gas desorption spectroscopy (TDS) test to determine the state and its amount of hydrogen in it. In the case that a potential of -0.5 VAg/AgCl was applied to the specimen in the solution of pH 3, the XRD detected no hydride on it. Whereas, application of -1.5 VAg/AgCl was induced formation of hydride. The TDS indicated that the specimen treated at -0.5 VAg/AgCl involved hydrogen desorbing around 810 K, and the one at -1.5 VAg/AgCl involved hydrogen desorbing around 500 as well as 810 K. Therefore, it was suggested that the hydrogen desorbing at lower and higher temperatures obtained by the TDS were of hydride state and solid-solution state, respectively. The specimens treated under various conditions were analyzed by the same way as mentioned before, and an amount of the hydrogen in each state as well as a cathodic charge density applied to the specimen were obtained to be correlated. A logarithm of the amount of the hydrogen in the each state increased almost linearly with an increase in a logarithm of a charge density. Susceptibility to the EAC of the material suddenly increased around a charge density of 0.025 MC·m-2, and the charge density was considered to induce the amounts of hydrogens in hydride and solid-solution state of 10 and 100 mass ppm, respectively

Theoretical Study of Singlet Oxygen Molecule Generation via an Exciplex with Valence-Excited Thiophene

Singlet-oxygen [O₂(¹Δ_g)] generation by valence-excited thiophene (TPH) has been investigated using multireference Møller–Plesset second-order perturbation (MRMP2) theory of geometries optimized at the complete active space self-consistent field (CASSCF) theory level. Our results indicate that triplet TPH­(1³B₂) is produced via photoinduced singlet TPH­(2¹A₁) because 2¹A₁ TPH shows a large spin–orbit coupling constant with the first triplet excited state (1³B₂). The relaxed TPH in the 1³B₂ state can form an exciplex with O₂(³Σ_g^–) because this exciplex is energetically more stable than the relaxed TPH. The formation of the TPH­(1³B₂) exciplex with O₂(³Σ_g^–) whose total spin multiplicity is triplet (T₁ state) increases the likelihood of transition from the T₁ state to the singlet ground or first excited singlet state. After the transition, O₂(¹Δ_g) is emitted easily although the favorable product is that from a 2 + 4 cycloaddition reaction