Abnormal spatial heterogeneity governing the charge-carrier mechanism in efficient Ruddlesden-Popper perovskite solar cells

Layered Ruddlesden-Popper perovskite (RPP) photovoltaics have gained substantial attention owing to their excellent air stability. However, their photovoltaic performance is still limited by the unclear real-time charge-carrier mechanism of operating devices. Herein, we report the correlation between the charge-carrier mechanism and the spatially heterogeneous RPP bulks induced by distinct sublattice cations in the state-of-the-art antisolvent-driven RPP devices. In particular, abnormal heterogeneities ranging from the lateral long-range to local sub-grain scale and corresponding charge-carrier behaviours are visualized for triple-cation RPPs. We discovered that such heterogeneities with a unitary 2D/3D hybrid suppress lattice vibrations and reduce Frohlich interactions by about 2 times, significantly promoting charge-carrier dynamics. Consequently, optimized triple-cation RPP solar cells greatly outperform their mono-cation counterparts. Furthermore, this principle can be applicable irrespective of 2D layer thickness (n > 2) and substrate type. This work provides a rationale for leveraging a disordered structure to stimulate charge-carrier motion and suggests the design principle of low-dimensional perovskites.

The complete chloroplast genome of Polygala tenuifolia, a critically endangered species in Korea

Polygala tenuifolia Willd. is an Oriental plant that is widely distributed in East Asia; but the medicinal plant is a critically endangered species in Korea, where only a few individuals exist. In spite of that, there have been no molecular conservation studies on P. tenuifolia. In this study, we elucidated the complete chloroplast (cp) genome of P. tenuifolia and investigated its phylogenetic position based on the cp genomes of related taxa. Results showed the cp genome was 165,423 bp in length, consisting of a large single-copy region of 83,699 bp, a small single-copy region of 8,044 bp, and two inverted repeat regions of 36,840 bp. In addition, the plastid genome contained 123 genes, including 85 protein-coding genes, 38 transfer RNA genes, and 8 ribosomal RNA genes. The present study is the first to report the complete cp genome of genus Polygala, information which may be valuable for future molecular phylogenetic and conservation studies on P. tenuifolia

Flora of Jeokgeunsan Mountain in the Civilian Control Zone, Gangwon-do, South Korea

The flora of Jeokgeunsan Mountain forest genetic resources protection zone was identified and the major flora distribution examined. From May 2011 to September 2012, the flora was made up of taxonomic groups including 84 families, 283 genera, 432 species, four subspecies, 59 varieties, and six forma. Eleven families and 16 taxonomic groups were endemic plants to Korea, and 13 taxonomic groups were rare flora of Korea designated by the National Forest Service. Eight families and 24 taxonomic groups for naturalized plants were confirmed and the naturalization rate was 4.8%. Out of 501 taxonomic groups, 404 were resource plants of which 208 (41.5%) were edible plants, 152 (30.3%) were medicinal plants, 199 (39.7%) were herbaceous plants, and 55 (11.0%) were ornamental plants

Comparison of species composition among Picea jezoensis (Siebold & Zucc.) carrière forests in Northeast Asia (from China to South Korea)

In this study, we aimed to provide basic data on the vegetation structure of the Picea jezoensis forest of Gyebangsan, Sobaeksan, Deogyusan, and Jirisan in South Korea and Baekdusan in China and to compare the abiotic and biotic factors correlated with the species composition of Picea jezoensis forests from South Korea and China. The Picea jezoensis forest stand structure was more stable in the Baekdusan region of China than in South Korea. In Sobaeksan, South Korea, a severe decline in Picea jezoensis was observed, and the basal area occupied by the species (2.89 ± 1.11 ㎡/ha; approximately 8% of the total basal area) was lower than that occupied by broad-leaved trees

Distribution characteristics of plants in the Ungseokbong Mountain, Gyeongsangnam-do, Korea

This study was conducted 13 surveys from 2007 through 2012. The surveys on the entire plants distribution in the Ungseokbong Mountain found 491 taxa in total: 99 families, 290 genera, 419 species, 3 subspecies, 61 varieties, and 8 forms. 1,211 specimens were secured as evidence. In particular, 11 taxa of the rare plants which were designated by the Korea Forest Service were confirmed, and 12 taxa of the endemic plants were confirmed in this study. Those plants above Class III of the specific plants designated by the Ministry of Environment were confirmed 19 taxa. Among them, in particular, it was confirmed that Kirengeshoma koreana Nakai has a new habitat in the Unseokbong. Naturalized plants included 34 taxa accounting for 6.9% were representatively confirmed

Floristic study of Gogunsan Archipelago, Jeollabuk-do, Korea

AbstractWe investigated the Gogunsan Islands from April 2012 to October 2012 for plant diversity. The vascular plants of Gogunsan Islands were recorded as total 565 taxa, 105 families, 333 genera, 502 species, 3 subspecies, 50 varieties, and 10 forms. Rare plants were observed 9 taxa. Korean endemic plants were 2 taxa, floristics special plants were 18 taxa, and naturalized plants were 72 taxa. Gogunsan Islands flora changes are in process slowly compared to earlier work thus, continuing interest and appropriate measures should be encouraged

Selective delivery of PLXDC1 small interfering RNA to endothelial cells for anti-angiogenesis tumor therapy using CD44-targeted chitosan nanoparticles for epithelial ovarian cancer

<p>Angiogenesis plays an essential role in the growth and metastasis of tumor cells, and the modulation of angiogenesis can be an effective approach for cancer therapy. We focused on silencing the angiogenic gene PLXDC1 as an important factor for anti-angiogenesis tumor therapy. Herein, we developed PLXDC1 small interfering siRNA (siRNA)-incorporated chitosan nanoparticle (CH-NP/siRNA) coated with hyaluronic acid (HA) to target the CD44 receptor on tumor endothelial cells. This study aimed to improve targeted delivery and enhance therapeutic efficacy for tumor anti-angiogenesis. The HA-CH-NP/siRNA was 200 ± 10 nm in size with a zeta potential of 26.4 mV. The loading efficiency of siRNA to the HA-CH-NP/siRNA was up to 60%. The selective binding of HA-CH-NP/siRNA to CD44-positive tumor endothelial cells increased by 2.1-fold compared with that of the CD44 nontargeted CH-NP/siRNA. PLXDC1 silencing by the HA-CH-NP/siRNA significantly inhibited tumor growth in A2780 tumor-bearing mice compared with that in the control group (<i>p</i> < .01), and mRNA expression of PLXDC1 was significantly reduced in the HA-CH-NP/siRNA-treated group. Furthermore, treatment with HA-CH-NP/siRNA resulted in significant inhibition of cell proliferation (<i>p</i> < .001), reduced microvessel density (<i>p</i> < .001), and increased cell apoptosis (<i>p</i> < .001). This study demonstrates that HA-CH-NP/siRNA is a highly selective delivery platform for siRNA, and has broad potential to be used in anti-angiogenesis tumor therapy.</p