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We report on a new metal halide perovskite photovoltaic cell that exhibits both very high solar-to-electric power-conversion efficiency and intense electroluminescence. We produce the perovskite films in a single step from a solution containing a mixture of FAI, PbI2, MABr, and PbBr2 (where FA stands for formamidinium cations and MA stands for(More)
The aromatic Schiff base N-salicylideneaniline (SA) represents the aristotype of a whole family of chromic derivatives. SA forms two photochromic polymorphs, R 1 and R 2 , both of which feature non-coplanar phenyl rings. Since many details of its reversible photoreactivity are still unexplained, we report the structure of a planar, thermochromic polymorph,(More)
The title compound, [Co(C(20)H(23)N(3)O(2))(C(5)H(11)N)](C(24)H(20)B) or [Co{(Me-sal)(2)dien}(pprdn)]BPh(4), where (Me-sal)(2)dien is 2,2'-[1,1'-(3-aza-pentane-1,5-diyldinitrilo)diethyl-idyne]diphenolate and pprdn is piperidine, contains a penta-dentate (Me-sal)(2)dien ligand furnishing an N(3)O(2) set, such that two of the N and one of the O atoms of the(More)
Lead halide perovskites have over the past few years attracted considerable interest as photo absorbers in PV applications with record efficiencies now reaching 22%. It has recently been found that not only the composition but also the precise stoichiometry is important for the device performance. Recent reports have, for example, demonstrated small amount(More)
Hydrothermally synthesized dipotassium gallium {hydrogen bis[hydrogenphosphate(V)]} difluoride, K(2)Ga[H(HPO(4))(2)]F(2), is isotypic with K(2)Fe[H(HPO(4))(2)]F(2). The main features of the structure are ([Ga{H(HPO(4))(2)}F(2)](2-))(n) columns consisting of centrosymmetric Ga(F(2)O(4)) octahedra [average Ga-O = 1.966 (3) Angstrom and Ga-F = 1.9076 (6)(More)
Differential geometry provides a useful mathematical framework for describing the fundamental concepts in crystallography. The notions of point and associated vector spaces correspond to those of manifold and tangent space at a given point. A space-group operation is a one-to-one map acting on the manifold, whereas a point-group operation is a linear map(More)
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