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Organic-inorganic perovskite solar cell materials have attracted considerable attention in recent years. Ag and Au are commonly employed as the counter electrode in such cells. In this study, molecular dynamics simulation were used to investigate the diffusion properties of Ag ions in α-CsPbI 3. Ag ions have the highest diffusion coefficient at temperatures between 318 K and 358 K. Density functional theory calculations were performed to study the effects of Ag diffusion on the band structures, crystal structures and optical absorption spectra of α-CsPbI 3 materials. The results suggest that, Ag ions have diffusion coefficients ranging from 0.6 × 10−6 cm2 × s−1 to 1.1 × 10−6 cm2 × s−1 in α-CsPbI 3 at temperatures between 278 K and 398 K. Ag doping can insert a Ag dopant level in α-CsPbI 3 and reduce the band gap of α-CsPbI 3. Furthermore, increasing the Ag content could reduce the energy gap between the Ag dopant level and the valence band or conduction band. • Treat Ag as a dopant to study the Ag diffusion effect in α-CsPbI3. • Using both DFT and MD simulation to discuss the Ag diffusion effect in α-CsPbI3. [ABSTRACT FROM AUTHOR]

Selenium (Se) supplementation is reported to decrease the incidence and total mortality of cancer. Whereas in vitro and in vivo studies have shown a decrease in prostate, lung, and liver cancers, this has not been shown in thyroid cancer. ARO (anaplastic), NPA (BRAF positive papillary), WRO (BRAF negative papillary), and FRO (follicular) cells treated with 150 μM seleno-l-methionine (SM) were assessed for viability at 24, 48, and 72 h. Treated FRO cells were examined for cell cycle using flow cytometry, for apoptosis using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, and for gene expression using microarray. Genes identified as upregulated were confirmed by real-time PCR (RT-PCR) and proteins by Western blot analysis. SM treatment significantly decreased the proliferation of all cell lines. TUNEL assay showed no evidence of apoptosis, and flow cytometry showed a significant cell-cycle arrest in S (271% increase, P= 0.006) and G2/M (61% increase, P= 0.002) compared to control. Microarray revealed 21 differentially expressed genes with greater than twofold change. A relative overexpression of growth arrest and DNA damage inducible (GADD)34 and GADD153 in treated cells was confirmed with RT-PCR and Western blot. SM inhibits thyroid cancer cell proliferation through a time dependent upregulation of the GADD family of genes and arrest in S and G2/M phases of the cell cycle. This is the first report of selenium induced inhibition of thyroid cancer cell growth. [ABSTRACT FROM AUTHOR]