Stable and efficient soft perovskite crystalline film based solar cells prepared with a facile encapsulation method.

The quasi Fermi level for electrons in a soft perovskite crystalline thin film and the contact qualities at the PCBM/perovskite and perovskite/P3CT-Na interfaces can be increased using a facile encapsulation method, which improves the device performance and stability of the resultant perovskite solar cells. In the encapsulated perovskite solar cells, the averaged open-circuit voltage (VOC) largely increases from 0.981 V to 1.090 V after 9 days mainly due to the increased quasi Fermi levels. Besides, the reflectance and photoluminescence (PL) spectra show improved contact qualities at the PCBM/perovskite and perovskite/P3CT-Na interfaces, which can be used to explain the increase in the short-circuit current density (JSC) from 21.68 mA cm-2 to 23.48 mA cm-2 after the encapsulation process. Besides, nanosecond time-resolved PL and temperature-dependent PL spectra can be used to explain the increased VOC, which is mainly due to the increased shallow defect density and thereby increasing the exciton binding energy of the encapsulated perovskite sample. It is noted that the averaged power conversion efficiency (PCE) slowly decreases from 18.24% to 16.52% within 45 days.

Targeted and oxygen-enriched polymeric micelles for enhancing photodynamic therapy.

Photodynamic therapy (PDT) has been emerged as an alternative therapeutic modality in treatment of several malignant tumors. However, the therapeutic efficacy of PDT is often limited by the solubility of photosensitizers, tumor hypoxia and lack of target specificity to cancer cells. In this study, we developed a folate-conjugated fluorinated polymeric micelle (PFFA) to deliver the hydrophobic photosensitizer (chlorin e6, Ce6) to overcome these limitations. The fluorinated micelles exhibit the low critical micelle concentration, good long-term stability, higher oxygen-carrying capacity and better singlet oxygen generation efficiency compared to non-fluorinated micelles, indicating the potential to improve the PDT efficacy in hypoxic conditions. Cytotoxicity of PDT effect and cellular uptake demonstrate the higher cell growth inhibition to HeLa cells upon irradiation attributed to the selective internalization of Ce6-loaded PFFA micelles (PFFA-Ce6). All results demonstrate the PFFA-Ce6 micelles with targeting function and oxygen-carrying capacity can serve as a promising drug delivery system for hydrophobic photosensitizers and improvement on PDT efficacy.