Enhancing Near-Infrared Absorption in Terpyridyl Ru/Os Complexes with Ancillary Ligands to Activate Spin-Forbidden Transitions in Dye-Sensitized Solar Cells: A TDDFT Investigation

Dye sensitizers with wideband absorption covering the near-IR region have long been of interest because they potentially harvest a wide range of solar energies essential to promote photocurrent power conversion efficiencies. In this study, we used time-dependent density functional theory with spin–orbit (SO) interactions to theoretically explore the long-wavelength absorptions and spin-forbidden triplet transitions activated by SO interactions for terpyridyl ruthenium/osmium complex dyes. These dyes feature a Ru(II) sensitizer coordinated with a phosphine ligand and are exemplified by DX1, denoted as [trans-dichloro-(phenyldimethoxyphosphine)(2,2′;6′,2″-terpyridyl-4,4′,4″-tricarboxylic)Ru]. We found that ancillary ligands significantly affected the longest wavelength spin-allowed absorption, with NCS– ligands yielding longer wavelength S1 transitions than halides. High atomic number halide ligands caused blue shifts in the S1 transition. Os complexes consistently exhibited longer wavelength S1 transitions than Ru complexes with identical ligands. In Ru/Os complexes, ancillary ligands with higher atomic numbers have a more pronounced effect in activating spin-forbidden triplet transitions through spin–orbit coupling (SOC) than those with lower atomic numbers. The absorption wavelength of the SOC-activated transition primarily depended on the energy of lower lying triplet states. Some complexes exhibited T1 states activated by SOC, leading to longer wavelength absorption than that of SOC-activated T2 states. Our study revealed the significance of ancillary ligands and SOC interactions in Ru/Os complexes, offering insights for optimizing materials with enhanced long-wavelength absorption properties, particularly in the near-IR range, for photovoltaic and optoelectronic applications

Unsymmetrical Squaraines Incorporating Quinoline for Near Infrared Responsive Dye-Sensitized Solar Cells

Two new unsymmetrical squaraines (<b>WCH-SQ10</b> and <b>WCH-SQ11</b>), wherein the electron-rich 3,4-ethylenedioxy-thiophene conjugated fragment was linked unconventionally to the squaraine core and triphenyl amine donor, and carboxylic acid substituted quinoline was used as an acceptor, were prepared. <b>WCH-SQ10</b> and <b>WCH-SQ11</b> dyes in ethanol have the λ_max of 686 and 673 nm, respectively. The corresponding photovoltaic devices exhibit an attractively panchromatic response over 1000 nm, suggesting that quinoline benefits the low energetic electron injection

Diastereoisomers of Ruthenium Dyes with Unsymmetric Ligands for DSC: Fundamental Chemistry and Photovoltaic Performance

A new thiocyanic acid-free ruthenium sensitizer, CYC-B29, containing two unsymmetrical ancillary ligands, was synthesized, and its three diastereoisomers CYC-B29-CC, CYC-B29-TT, and CYC-B29-CT with significantly different optical, electronic, and electrochemical properties were carefully separated. CYC-B29-TT with the smallest size has the strongest absorption coefficient of the MLCT band, the shortest λ_max, the lowest highest occupied molecular orbital level and the highest dye loading. Therefore, dye-sensitized solar cell based on CYC-B29-TT has the highest efficiency, which is two times higher than that of CYC-B29-CC-sensitized device and 10% higher than that of N719-based cell. Time-dependent density functional theory-calculated transition bands for the three isomers are not identical, and only CYC-B29-TT has the calculated transition bands close to the experimental absorption profile. Although the calculated transition bands for CYC-B29-CC and CYC-B29-CT are not consistent with the experimental data, the ground-state vertical excitation energy with oscillator strength and electron-density difference map data combining with the dye loading predict correctly the order of the photocurrent for the three isomers sensitized devices

The rs16906252:C>T SNP is not associated with increased overall survival or temozolomide response in a Han-Chinese glioma cohort

<div><p>The methylation status of O-6-methylguanine-DNA methyltransferase (MGMT) is associated with the prognosis in gliomas and in other cancers. Recent studies showed that rs16906252, an SNP in the <i>MGMT</i> promoter, is associated with promoter methylation and is a predictor of the overall survival time (OST) and the response to temozolomide (TMZ) treatment. However, these findings haven’t been systematically investigated in the Han-Chinese population. We analyzed the relevance between rs16906252 polymorphisms, the <i>MGMT</i> methylation status, and the OST in 72 Han-Chinese gliomas patients. The <i>MGMT</i> promoter methylation was measured by bisulfite conversion followed by pyro-sequencing, while rs16906252 was measured by restriction endonuclease digestion. Contrary to the previous findings, we found no association between rs16906252 genotypes and promoter methylation on <i>MGMT</i>. The lower-grade glioma (LGGs) patients carrying the C allele with rs16906252 showed a surprisingly better OST (P = 0.04). Furthermore, the LGG patients carrying hypo-methylated <i>MGMT</i> promoter and rs16906252 T allele showed significantly poorer prognosis. The prognostic benefit of <i>MGMT</i> promoter methylation and genotypes on gliomas patients is marginal. A new molecular stratified patient grouping of LGGs is potentially associated with poorer OST. Active MGMT might have a protective role in LGG tumors, enabling evolution to severe malignancy.</p></div

The Changes of Cerebral Morphology Related to Aging in Taiwanese Population

<div><p>A cross-sectional study with the 3-dimensional (3D) MRI reconstruction technique was conducted to investigate cerebral complexity changes related to age differences in native Taiwanese population. In our sample of 85 participants aged between 25 and 81, age was associated with gradual ventricular expansion. A nonlinear quadratic relationship between white matter volume and age was found overall in the brain. Widespread age-related reduction in white matter was detected from late adulthood onwards. However, no significant age-related changes in the cortex and whole brain volume were determined throughout adulthood. These findings provided information in describing brain structural complexity, which might in the future serve as an objective diagnostic index or as a predictive parameter for neurological diseases. Our method then may be used for cross-cultural longitudinal studies to evaluate the effect of disease, environment and aging on the brain.</p> </div

Regression models.

a.<p>ref.: reference group.</p>b.<p>LRT: likelihood ratio test, for testing the non-linear the association between age and dependent variables.</p

Correlation between the rs16906252 genotype and promoter methylation.

<p><i>MGMT</i> promoter methylation and the rs16906252 genotype were analyzed for association with (A) all glioma patients (P = 0.5573), (B) glioblastoma patients (P = 0.9899), and (C) LGG patients (P = 0.5827). Neither all nor subgroups of patients replicated the previously reported association in the Han-Chinese.</p

Kaplan-Meier survival analysis on the extent of <i>MGMT</i> promoter methylation.

<p>In glioblastoma patients, most patients (68%) showed hypo-methylation, but this was opposite in LGG patients (32%). Statistical analysis suggests that the OST is not associated with <i>MGMT</i> promoter methylation on (A) glioblastoma patients (P = 0.5029) and (B) LGG patients (P = 0.9555).</p

Kaplan-Meier survival analysis on the glioblastoma patients with and without TMZ treatment.

<p>Among 34 glioblastoma patients, only 9 patients were not treated with TMZ. The patients treated with TMZ showed a prolonged OST compared to the group without TMZ, although this is not statistically significant (P = 0.1256).</p

OST and the <i>MGMT</i> promoter genotype and methylation on LGGs.

<p>The LGG patients were further classified with (A) hyper- and (B) hypo-methylated promoter in <i>MGMT</i>. The C (or T) allele is not associated with a prolonged OST on patients with methylated promoter (A, P = 0.7096) but on patients of hypo-methylation (B, P = 0.0252).</p