ZnO@SnO2 engineered composite photoanodes for dye sensitized solar cells

Layered multi-oxide concept was applied for fabrication of photoanodes for dye-sensitized solar cells based on ZnO and SnO2, capitalizing on the beneficial properties of each oxide. The effect of different combinations of ZnO@SnO2 layers was investigated, aimed at exploiting the high carrier mobility provided by the ZnO and the higher stability under UV irradiation pledged by SnO2. Bioxide photoanodes performed much better in terms of photoconversion efficiency (PCE) (4.96%) compared to bare SnO2 (1.20%) and ZnO (1.03%). Synergistic cooperation is effective for both open circuit voltage and photocurrent density: enhanced values were indeed recorded for the layered photoanode as compared with bare oxides (V-oc enhanced from 0.39 V in case of bare SnO2 to 0.60 V and J(sc) improved from 2.58 mA/cm(2) pertaining to single ZnO to 14.8 mA/cm(2)). Improved functional performances of the layered network were ascribable to the optimization of both high chemical capacitance (provided by the SnO2) and low recombination resistance (guaranteed by ZnO) and inhibition of back electron transfer from the SnO2 conduction band to the oxidized species of the electrolyte. Compared with previously reported results, this study testifies how a simple electrode design is powerful in enhancing the functional performances of the final device

Dye-sensitized solar cells based on a push-pull zinc phthalocyanine bearing diphenylamine donor groups: computational predictions face experimental reality

Computational studies have suggested that the integration of secondary amine as donor groups in the structure of unsymmetrical zinc phthalocyanine (ZnPc) should have positive effects on photovoltaic performance, once the molecule is integrated as light harvester in dye sensitized solar cells (DSSCs). Aiming at obtaining experimental confirmation, we synthesized a peripherally substituted push-pull ZnPc bearing three electron donating diphenylamine substituents and a carboxylic acid anchoring group and integrated it as sensitizer in TiO2-based DSSCs. Detailed functional characterization of solar energy converting devices resulted in ruling out the original hypothesis. The causes of this discrepancy have been highlighted, leading to a better understanding of the conditions for an effective design of push-pull diarylamino substituted ZnPcs for DSSCs

Serious complications of pancreatoduodenectomy correlate with lower rates of adjuvant chemotherapy: Results from the recurrence after Whipple's (RAW) study

Introduction: Adjuvant chemotherapy (AC) can prolong overall survival (OS) after pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC). However, fitness for AC may be influenced by postoperative recovery. We aimed to investigate if serious (Clavien-Dindo grade ≥ IIIa) postoperative complications affected AC rates, disease recurrence and OS. Materials and methods: Data were extracted from the Recurrence After Whipple's (RAW) study (n = 1484), a retrospective study of PD outcomes (29 centres from eight countries). Patients who died within 90-days of PD were excluded. The Kaplan-Meier method was used to compare OS in those receiving or not receiving AC, and those with and without serious postoperative complications. The groups were then compared using univariable and multivariable tests. Results: Patients who commenced AC (vs no AC) had improved OS (median difference: (MD): 201 days), as did those who completed their planned course of AC (MD: 291 days, p < 0.0001). Those who commenced AC were younger (mean difference: 2.7 years, p = 0.0002), more often (preoperative) American Society of Anesthesiologists (ASA) grade I-II (74% vs 63%, p = 0.004) and had less often experienced a serious postoperative complication (10% vs 18%, p = 0.002). Patients who developed a serious postoperative complication were less often ASA grade I-II (52% vs 73%, p = 0.0004) and less often commenced AC (58% vs 74%, p = 0.002). Conclusion: In our multicentre study of PD outcomes, PDAC patients who received AC had improved OS, and those who experienced a serious postoperative complication commenced AC less frequently. Selected high-risk patients may benefit from targeted preoperative optimisation and/or neoadjuvant chemotherapy