Optical properties of oligothiophene substituted diketopyrrolopyrrole derivatives in solid phase : joint J and H-type aggregation

Photophysical properties of diketopyrrolopyrrole derivatives substituted with oligothiophenes are investigated. All compounds are found to be fluorescent both in solution and in the solid phase. At low temperature in the solid, fluorescence originates from excimer-like excited states. Comparison of absorption and fluorescence excitation spectra taken under matrix isolated conditions and on solid films show the presence of both J- and H-type absorption bands in the solid phase. Quantum-chemical calculations, including exciton-phonon coupling to account for deviations from the Born-Oppenheimer approximation, are performed to simulate the band shape of the lowest absorption band in the molecular solid. The joint presence of J- and H-bands is explained by the presence of two molecules in the unit cell. The Davydov splitting is substantial for molecules with linear alkyl substituents on the nitrogen atom (on the order of 0.2 eV) but can be reduced to almost zero by introducing branching at the ß-carbon of the alkyl side chain

Optical properties of oligothiophene substituted diketopyrrolopyrrole derivatives in solid phase : joint J and H-type aggregation

Photophysical properties of diketopyrrolopyrrole derivatives substituted with oligothiophenes are investigated. All compounds are found to be fluorescent both in solution and in the solid phase. At low temperature in the solid, fluorescence originates from excimer-like excited states. Comparison of absorption and fluorescence excitation spectra taken under matrix isolated conditions and on solid films show the presence of both J- and H-type absorption bands in the solid phase. Quantum-chemical calculations, including exciton-phonon coupling to account for deviations from the Born-Oppenheimer approximation, are performed to simulate the band shape of the lowest absorption band in the molecular solid. The joint presence of J- and H-bands is explained by the presence of two molecules in the unit cell. The Davydov splitting is substantial for molecules with linear alkyl substituents on the nitrogen atom (on the order of 0.2 eV) but can be reduced to almost zero by introducing branching at the ß-carbon of the alkyl side chain

Access to Urological Care for Medicaid-Insured Patients at Urology Practices Acquired by Private Equity Firms.

ObjectiveTo characterize appointment access for Medicaid-insured patients seeking care at urology practices affiliated with private equity firms in light of the recent national trends in practice consolidation.MethodsWe identified 214 urology offices affiliated with private equity firms that were geographically matched with 231 non-private equity affiliated urology offices. Using a standardized script, researchers posed as an adult patient with either Medicaid or commercial insurance in the clinical setting of new onset, painless hematuria. The primary outcome was whether the patient's insurance was accepted for an appointment. The secondary outcome was appointment wait time.ResultsWe conducted 815 appointment inquiry calls to 214 private equity (PE) and 231 non-PE-affiliated urology offices across 12 states. Appointment availability was higher for commercially-insured patients (99.0%; 95% CI: 98.1%-99.9%) vs Medicaid-insured patients (59.8%; 95% confidence interval [CI]: 55.0%-64.6%) (P < .0001). Medicaid acceptance was higher at non-PE affiliated (66.8%; CI 60.4%-73.2%) than PE-affiliated practices (52.1%; 95% CI 45.0%-59.2%) (P = .003). On multivariable logistic regression analysis, state Medicaid expansion status (odds ratio [OR] 2.20; CI 1.14-4.28; P = .020) was independently associated with Medicaid appointment availability, whereas PE-affiliation (OR 0.55; CI 0.37-0.83; P = .004) was independently associated with lower Medicaid access. Appointment wait times did not differ significantly for commercially-insured vs Medicaid patients (19.2 vs 20.1 days; p = .59), but PE-affiliated practices offered shorter mean wait times than non-PE offices (17.5 vs 21.4 days; P = .017).ConclusionAccess disparities for urologic evaluation in patients with Medicaid insurance at urology practices and were more pronounced at private equity acquired practices

Energetics of Electron\u2013Hole Separation at P3HT/PCBM Heterojunctions

The energetics of electronhole separation at the prototypical donor-acceptor interface P3HT/PCBM is investigated by means of a combination of molecular dynamics simulations, quantum-chemical methods, and classical microelectrostatic calculations. After validation against semiempirical Valence Bond/Hartree-Fock results, microelectrostatic calculations on a large number of electron-hole (e-h) pairs allowed a statistical study of charge separation energetics in realistic morphologies. Results show that charge separation is an energetically favorable process for about 50% of interfacial e-h pairs, which provides a rationale for the high internal quantum efficiencies reported for P3HT/PCBM heterojunctions. Three effects contribute to overcome the Coulomb attraction between electron and hole: (i) favorable electrostatic landscape across the interface, (ii) electronic polarization, and (iii) interface-induced torsional disorder in P3HT chains. Moreover, the energetic disorder due to the PCBM polar group is shown to play a key role in increasing the dissociation probability