In addition to the known effect of substrate on interfacial properties of perovskite films, here we show that bulk properties of Hybrid Lead Halide Perovskite films depend on the type of substrate used for film growth. Despite the relative large film thickness, ~600 nm, the roughness and nature of the substrate layer (glass, FTO, TiO 2 and PEDOT:PSS) affect not just the degree of preferential orientation and crystal grain size Raman peaks.The irreversible photoluminescence enhancement observed at low power with illumination time, also dependent on the substrate nature, is proposed to be due to the localization of the electron-hole excitons created in the vicinity of the light generated defects. The results shed light into the performance of the perovskite layer and help understanding how bulk processes, where ion migration is a conspicuous example, are severely affected by interfacial properties as those imposed by the substrate.

In this work, conditions of Suzuki condensation and polymer modification of polymers of benzene and fluorene units have been studied. A new polymer was prepared with statistical equimolecular amounts of two 2,7-dibromo-9,9-bis(6′-susbtituted-hexyl)fluorene as starting monomers. The C9 position of the poly[9,9-bis(6′-bromohexylfluoren-2,7-diyl)-alt-co-(benzen-1,4-diyl has been substituted yielding poly-[9,9-bis(6′-cyanohexylfluoren-2,7-diyl)-alt-co-(benzen-1,4-diyl)] with a high degree of conversion. All polymers were completely soluble in THF and chloroform and were characterized by NMR, FTIR, and elemental analysis. Molecular weights measured by gel permeation chromatography coupled with light scattering detector results in polydispersity values between 3.3 and 1.2. Their glass transitions temperature were over 90 and 99 °C by DSC. Comparative studies of optical properties in solution and solid state show similar values indicating that the remote substitution of functional group maintains the spectroscopic characteristics of the backbone. Cyclic voltammetry studies and preliminary results in bias potentials of electroluminiscent devices reveal that these polymers may be promising candidates to be used as hole and electron transporting materials.

Solution-processed near-infrared organic light-emitting diodes (NIR-OLEDs) with structure glass/indium–tin oxide/poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)/Er-complex/Ca/Al based on a novel Er(III) complex, [Er(tfnb)3(bipy)] (Htfnb = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione and bipy = 2,2′-bipyridine) have been manufactured and their properties have been studied. A complete quenching of the organic ligand visible emission is shown, and only the sensitized 1.5 μm electroluminesce from Er(III) results. From the electrical characteristic we present the mobility dependence on applied voltage using a numerical model, comparing it to poly(9,9-dioctylfluorene), a commercial semiconducting polymer with optical properties close to those of the molecular ligands. The synthesis of the novel complex together with a detailed analysis of its structure elucidated by XRD, 1H NMR, Raman, and Fourier-transform infrared spectroscopies is presented. A wide-ranging characterization of its photophysical properties in terms of absorption and steady and transient photoluminescence is used to investigate the energy-transfer process from the organic ligand to the central Er(III) ion.

Three novel ternary Er 3+ complexes emitting in the C band transmission window for fiber optic communications have been synthesised and their structures have been elucidated by single crystal X-ray diffraction. The fluorinated b-diketonate ligand, 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione, combines a good absorption cross-section in the ultraviolet region with reduction of non-radiative quenching of the Er 3+ emission, while the rigidity and bulkiness of the three different N,N-donors (2,2 0 -bipyridine, bathophenanthroline and 5-nitro-1,10-phenanthroline) have a pronounced impact on the emission intensity of luminescence. Furthermore, the choice of the ancillary ligand also determines the efficiency of the antenna effect, leading to complete quenching of the ligand-associated visible emission for the optimized complex with 5-nitro-1,10-phenanthroline. Solution processed 1.54 mm organic light-emitting diodes have been manufactured and characterized for this complex, confirming the aforementioned complete resonant energy transfer from the ligands to the Er 3+ ion. The features of the reported device fabrication show a simple way to obtain large area NIR-OLEDs.