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Antimony/bismuth-based organic–inorganic hybrid halide perovskite-like compounds have generated enormous research interest due to their excellent optical properties. Exploration of new compounds and understanding of their structural stability and optoelectronic properties is of utmost importance for practical applications of these materials. We report two new 0D perovskite-like compounds and their solid solution, (C3H7NH3)4Bi1−xSbxI9, having propyl amine as the spacer cation and iodine as the halide ion. All compounds crystallized in the space group C2/m at room temperature and undergo a phase transition from C2/m to P21/c at low temperature (90 K) as observed from the single-crystal study. A low-temperature (250 K, 180 K, 150 K and 90 K) single-crystal study shows that the (PA)4BiI9 compound retains the monoclinic space group C2/m until 150 K and undergoes a phase transition to the P21/c space group at 90 K. Further, it is observed that ordering, rearrangement and relaxation of the long-chain propyl amine group are primarily responsible for the structural transition. The structure contains [(Bi/Sb)I6]3− polyhedra along with linear I3− units, giving rise to the formula of (PA)3(Bi/Sb)I6·(PA)I3. The I3− units interact poorly while the [MI6]3− (M = Bi, Sb) octahedral units interact significantly with spacer cations via the H-bond, resulting in more distortion in these octahedral units. Theoretical calculations revealed that iodide ions have dual roles and contribute largely to both the valence band maxima and conduction band minima in these compounds. From both experimental and theoretical calculations, it is observed that the pristine compounds are of the indirect band gap-type and Sb substitution in (PA)4Bi1−xSbxI9 led to a gradual decrease in the band gap. [ABSTRACT FROM AUTHOR]

Introduction: Teenage pregnancy is a subject of concern among adolescents. Inadequate knowledge and misperceptions about pregnancy are major contributing factors to teenage pregnancy. Without a proper understanding, adolescents are involved in unsafe sexual practices, which results in pregnancy. So, perception and understanding are important aspects to explore among adolescents. In this planned scope review, all eligible studies will be identified around the perception, practices, and understanding of teenage pregnancy among married and unmarried adolescent girls. Methods: The Arksey and O'Malley (2005) scoping review framework and the Joanna Briggs Institute Reviewers' Manual (2015) will be used for the planned scoping review. The population, concept, and context strategy (PCC) will be used to develop the research question, search strategy, and eligibility criteria. Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Reviews (PRISMA ScR) will be used for the findings of the study. For the literature search, authors will use Google Scholar, PubMed, and ResearchGate electronic databases with specific words such as "teenage", "adolescence", "pregnancy", "perception", "knowledge", "awareness" and "abortion". Result: The planned scoping review will be helpful in addressing the lack of adolescent misperception, malpractices, and misunderstandings regarding teenage pregnancy. It can provide detailed information about teenage pregnancy in the Indian context. Conclusion: The evidence synthesis and gap analysis will be helpful in suggesting insights into the issue of teenage pregnancy, which will be helpful in future policies and programs. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of the solid solutions of 1D lead-free halide perovskites, (C2H5NH3)2BiCl5−xBrx (x = 0–5), using a solution method. All the synthesized compounds adopt the orthorhombic Cmca space group at room temperature (RT) (293 K) and undergo a phase transition to a low symmetry orthorhombic space group, Aba2, at a low temperature (LT) of 90 K. All the structures contain BiX6 (X = Cl or Br) corner-sharing polyhedra, forming zigzag 1D chains. The symmetry breaking phase transition from Cmca (293 K) to Aba2 (90 K) is due to the ordering of the ethylamine (removal of mirror plane) unit caused by strong H-bond formation in the low-temperature phase (LT phase). The TGA analysis indicates that (EA)2BiCl5 (EA = C2H5NH3+) is less stable than its bromine analogue. Optical studies show that all the compounds are of indirect band gap type with a band gap of 3 eV for the pristine chlorine compound and 2.5 eV for the pristine bromine compound. The band gap value gradually decreases with the incorporation of bromine at the chlorine site, following Vegard's law. According to the dielectric measurement, the pristine chlorine compound (x = 0) has a dielectric constant (εr) of 530, whereas that of the pristine bromine compound (x = 5) is 106 at room temperature and 10 kHz frequency. [ABSTRACT FROM AUTHOR]

Lead-free hybrid halide perovskites have recently gained enormous research attention because of their excellent optical properties. Herein, we report a novel zero-dimensional (0D) hybrid halide perovskite, (TMS)2BiBr5·DMSO, stabilized by the dimethyl sulfoxide (DMSO) solvent. The structure contains isolated [BiBr5OS(CH3)2]2− anionic polyhedra and the cations [(CH3)3S]+ (trimethyl sulfonium ion, TMS) balance the charge, making it a 0D halide perovskite. Non-interaction of the trans Br atoms (with respect to the Bi–DMSO bond) with the cationic TMS resulted in shorter trans Bi–Br bonds as compared to other Bi–Br bonds in the isolated BiBr5·DMSO polyhedra. The optical properties study reveals that the compound is an indirect band gap type with a band gap of 2.79 eV. From the PL study it is observed that the compound shows emission in the blue region. [ABSTRACT FROM AUTHOR]

Antimony/bismuth-based organic-inorganic hybrid halide perovskite-like compounds have generated enormous research interest due to their excellent optical properties. Exploration of new compounds and understanding of their structural stability and optoelectronic properties is of utmost importance for practical applications of these materials. We report two new 0D perovskite-like compounds and their solid solution, (C 3 H 7 NH 3 ) 4 Bi 1- x Sb x I 9 , having propyl amine as the spacer cation and iodine as the halide ion. All compounds crystallized in the space group C 2/ m at room temperature and undergo a phase transition from C 2/ m to P 2 1 / c at low temperature (90 K) as observed from the single-crystal study. A low-temperature (250 K, 180 K, 150 K and 90 K) single-crystal study shows that the (PA) 4 BiI 9 compound retains the monoclinic space group C 2/ m until 150 K and undergoes a phase transition to the P 2 1 / c space group at 90 K. Further, it is observed that ordering, rearrangement and relaxation of the long-chain propyl amine group are primarily responsible for the structural transition. The structure contains [(Bi/Sb)I 6 ] 3- polyhedra along with linear I 3 - units, giving rise to the formula of (PA) 3 (Bi/Sb)I 6 ·(PA)I 3 . The I 3 - units interact poorly while the [MI 6 ] 3- (M = Bi, Sb) octahedral units interact significantly with spacer cations via the H-bond, resulting in more distortion in these octahedral units. Theoretical calculations revealed that iodide ions have dual roles and contribute largely to both the valence band maxima and conduction band minima in these compounds. From both experimental and theoretical calculations, it is observed that the pristine compounds are of the indirect band gap-type and Sb substitution in (PA) 4 Bi 1- x Sb x I 9 led to a gradual decrease in the band gap.

Antimony/bismuth-based lead-free hybrid halide defect 2D perovskites have been generating enormous research interest due to their inherent excellent optical properties. Exploration of new phases and understanding of their structural and optoelectronic properties are of paramount importance in the process of developing materials for practical solar cell applications. In this article, we have reported a structural transition from the 0D hexagonal phase containing isolated [M 2 I 9 ] 3- (M = Bi/Sb) units to the 1D orthorhombic phase via a new monoclinic phase with novel isolated trimeric [M 3 I 12 ] 3- units in (C 2 H 5 NH 3 ) 3 Bi 2-2 x Sb 2 x I 9 . The hexagonal phase is stable up to 2 x = 0.6 in (C 2 H 5 NH 3 ) 3 Bi 2-2 x Sb 2 x I 9 . With gradual substitution of Sb, the cation-cation repulsion increases, which destabilizes the [M 2 I 9 ] 3- unit, and hence, the hexagonal phase becomes unstable. At intermediate composition, 2 x = 0.8-1.6, a new monoclinic phase (S.G.: C 2/ m ) with the composition (C 2 H 5 NH 3 ) 2 Bi 2-2 x Sb 2 x I 8 is formed, containing isolated [M 3 I 12 ] 3- units. The symmetry reduction resulted in larger distortion, which relaxes the strain and stabilizes the trimeric unit in the intermediate compositions. Finally, at higher Sb compositions (2 x = 1.9-2.0), the compounds crystallize in the orthorhombic 1D phase. In all three phases of (C 2 H 5 NH 3 ) 3 Bi 2-2 x Sb 2 x I 9 , the cationic ethylammonium units are completely disordered over the whole unit cell. Raman study clearly shows the phase transition in (C 2 H 5 NH 3 ) 3 Bi 2-2 x Sb 2 x I 9 and also the structural distortion in (C 2 H 5 NH 3 ) 2 Bi 2-2 x Sb 2 x I 8 . Optical property study shows that all the compounds are of indirect band gap type. Furthermore, PL study shows better emission properties of the 1D orthorhombic Sb compounds as compared to the 0D hexagonal and monoclinic phases.

Lead-free hybrid halide perovskites have recently gained enormous research attention because of their excellent optical properties. Herein, we report a novel zero-dimensional (0D) hybrid halide perovskite, (TMS) 2 BiBr 5 ·DMSO, stabilized by the dimethyl sulfoxide (DMSO) solvent. The structure contains isolated [BiBr 5 OS(CH 3 ) 2 ] 2- anionic polyhedra and the cations [(CH 3 ) 3 S] + (trimethyl sulfonium ion, TMS) balance the charge, making it a 0D halide perovskite. Non-interaction of the trans Br atoms (with respect to the Bi-DMSO bond) with the cationic TMS resulted in shorter trans Bi-Br bonds as compared to other Bi-Br bonds in the isolated BiBr 5 ·DMSO polyhedra. The optical properties study reveals that the compound is an indirect band gap type with a band gap of 2.79 eV. From the PL study it is observed that the compound shows emission in the blue region.