The efficiency of organic bulk heterojunction solar cells strongly depends on the multiscale morphology of the interpenetrating polymer-fullerene network. Understanding the molecular assembly and the identification of influencing parameters is essential for a systematic optimization of such devices. Here, we investigate the molecular ordering during the drying of doctor-bladed polymer-fullerene blends on PEDOT:PSS-coated substrates simultaneously using in situ grazing incidence X-ray diffraction (GIXD) and laser reflectometry. In the process of blend crystallization, we observe the nucleation of well-aligned P3HT crystallites in edge-on orientation at the interface at the instant when P3HT solubility is crossed. A comparison of the real-time GIXD study at ternary blends with the binary phase diagrams of the drying blend film gives evidence of strong polymer-fullerene interactions that impede the crystal growth of PCBM, resulting in the aggregation of PCBM in the final drying stage. A systematic dependence of the film roughness on the drying time after crossing P3HT solubility has been shown. The highest efficiencies have been observed for slow drying at low temperatures which showed the strongest P3HT interchain π-π-ordering along the substrate surface. By adding the "unfriendly" solvent cyclohexanone to a chlorobenzene solution of P3HT:PCBM, the solubility can be crossed prior to the drying process. Such solutions exhibit randomly orientated crystalline structures in the freshly cast film which results in a large crystalline orientation distribution in the dry film that has been shown to be beneficial for solar cell performance.

We investigate the 3.32 eV defect-related emission band in GaN correlating transmission electron microscopy and spatially and spectrally resolved cathodoluminescence at low temperature. The band is unambiguously associated with basal plane stacking faults of type I 2 , which are a common defect type in semi-and nonpolar GaN grown on foreign substrates. We ascribe the luminescence to free-to-bound transitions. The suggested intrinsic acceptors involved have an ionization energy of ≈0.17 eV, and are located at the I 2 -type basal plane stacking faults.

No abstract

The aim of the study was to characterize the vitality and age of skin wounds by the detection of selectins. A prospective study was conducted for this purpose in which 197 vital human skin wounds (time since injury ranging from 3 min to 790 days) were investigated immunohistologically. Of the samples tested, 97 were taken from autopsy material and 100 from patient material from the department of surgery at the university hospital. The selectins were detected in paraffin sections after autoclaving and using the ABC technique. The intensity was rated by a semi-quantitative evaluation using a four-stage ordinal scale. Strong positive immunohistochemical reactions were observed for the P-selectin 3 min at the earliest and 7 h at the latest after the time of injury. For the E-selectin a positive staining was evident 1 h at the earliest and 17 days at the latest from the time the skin was injured. The staining intensity decreased significantly after an interval of 12 h from the time of injury (P < 0.05). The L-selectin was regularly detected on leukocytes in thesamples of injured skin. The immunohistochemical results for the P-and E-selectins were significantly different between injured and uninjured skin (P < 0.01). The expression of the selectins is indicative of the vitality of the wound. P-selectin was detected in a few cases (n = 4) at low intensity while E-selectin could not be found in the control samples (n = 31) of postmortem skin wounds. The use of P-and E-selectins for forensic purposes can help to achieve better estimates of the age of wounds with short survival times.

To characterize the vitality and age of skin wounds by means of the ICAM-1 pattern, 157 intravital human skin wounds (time since injury ranging from 5 min to 730 days) were immunohistochemically investigated. ICAM-1 was detected in paraffin sections after autoclaving and using the ABC technique in 86% of the wounds investigated. The correlation between ICAM-1 expression and the degree of wound inflammation is weak. Strong positive staining was observed 1.5 h at the earliest and 3.5 days at the latest after the time of injury. ICAM-1 also appeared at low concentrations in samples of uninjured skin (n = 65), on keratinocytes and the endothelial cells of blood vessels. Moderate to strong ICAM-1 expression is a valuable indication of the vitality of the wound. However, at present the detection of ICAM-1 alone is not sufficient to fix the wound age with the accuracy which is required for forensics applications. PIC = perivascular infiltration cells, bKC = basal keratinocytes, KC = keratinocytes, EC = endothelial cells PIC = perivascular infiltration cells, bKC = basal keratinocytes, KC = keratinocytes, EC = endothelial cells