Examinando por Autor "Harbuzaru, Alejandra"

Mostrando 1 - 2 de 2

Comparing the microstructure and photovoltaic performance of 3 perylene imide acceptors with similar energy levels but different packing tendencies
(Royal Society of Chemistry, 2022) Adel, Rana; Gala, Elena; Alonso-Navarro, Matías J.; Gutierrez-Fernandez, Edgar; Martín, Jaime; Stella, Marco; Martinez-Ferrero, Eugenia; de la Peña, Alejandro; Harbuzaru, Alejandra; Ramos, M. Mar; Ponce Ortíz, Rocío; Segura, José L.; Campoy-Quiles, Mariano
While it is widely recognized that microstructure plays an important role in the performance of organic photovoltaics (OPV), systematic studies are often challenging, as varying the molecular packing through typical chemical means (such as sidechain tuning) often affects the molecular energy levels, thus preventing a clear correlation. In this work we present the synthesis of three perylene imide (PI) based electron acceptors with almost identical energy levels, but distinct packing tendencies. We confirm our initial hypothesis by measuring solution and solid-state absorption, and cyclic voltammetry as well as characterizing the films by grazing incidence wide angle X-ray scattering (GIWAXS). In a second step, we repeat the characterization of the three materials in blends with two polymer donors, namely PCDTBT or PBDBT, whose energy levels are well aligned with those of the PI acceptors, and which, additionally, exhibit different degrees of structural order. We show how the initial strong difference between acceptors is partially blurred in blends, but still critical. Finally, we correlate our structural data with OPV devices made with the corresponding six blends. Our data suggest that a good donor acceptor marriage should ensure good energy alignment but also exhibit complementary crystallization tendencies of the two components.
Naphthalimide-Based 3D Organic Semiconductors: Synthesis and Application as Photo-Electrocatalysts for Organic Dyes Degradation and Water Splitting
(Wiley-VCH GmbH, 2023) Suárez-Blas, Fátima; Junyi, Li; Alonso-Navarro, Matías J.; Harbuzaru, Alejandra; Ponce Ortíz, Rocío; Ramos, María Mar; Shalom, Menny; Barrio, Jesús; Segura, José L.
1,2-diketone-based naphthalimide has emerged as an important electronwithdrawing building block in the synthesis of organic semiconductor assemblies for a wide range of applications. The reaction with different diamine derivatives enables the formation of pyrazine linkers which promotes planarity and rigidity of the naphthalimide-based semiconductors, therefore tunning their electronic structure and processability. Despite the significant use of this versatile building block to generate flat and rigid assemblies, the correlation between rigidity and dimensionality in these systems and their photocatalytic activity remains unexplored so far. Herein, with the aim to modulate the photocatalytic activity of these materials, a new family of assemblies with different dimensionality end-capped with naphthalimide moieties are developed in which one (NIPB), three (3NIPT), and four (4NIPTM) units have been selectively introduced. The good processability of these novel semiconductors combined with their suitable energy levels allows their application as photo-electrocatalysts for the degradation of organic dyes and for water splitting. The derivative with the highest dimensionality, 4NIPTM, shows higher photo-electrocatalytic activity and lower charge transfer resistance than that of conventional semiconductors (such as TiO2 and C3N4), reaching photocurrents up to 20 mA cm−2.