Organic ambipolar semiconductors for TFT applications

In the last years we have devoted some effort to the search of new high-mobility semiconductors with ambipolar performances, good processability and environmental stability. Our approach, which is one of the most widely used, consists in the combination of donor and acceptor moieties in the conjugated skeleton, which allows fine tuning of the frontier molecular orbitals. For OTFT applications, low-lying HOMOs are essential to resist air oxidation and thus increase device stability. However, if the HOMO energy is too low, the resulting barrier to hole injection may compromise the transistor performance. Thus, a delicate balance between these two effects is needed. In particular, we have combined naphthaleneimide-derived moieties as electron accepting groups with electron-rich oligothiophene fragments. In these materials, we have found that the presence of ambipolar transport in these planar molecules can be understood on the basis of three interrelated properties: (i) the absence of skeletal distortions allows closer intermolecular pi-pi stacking and enhanced intramolecular pi-conjugation, (ii) increased pi-conjugation raises the HOMO energy, which approaches the Fermi level of common used electrodes; and (iii) more planar structures translate into lower Marcus reorganization energies. However, one of the limitations of these types of semiconductors is the presence of a molecular dipole moment, which forces the molecules to pack with pairwise intermolecular interactions orienting the naphthaleneimide cores in opposite directions, decreasing in some cases molecular orbitals overlapping. In recent contributions, we have devoted our efforts to analyze the effect of molecular interactions, through chemical modifications in order to induce parallel and antiparallel molecular packing, on the electronic properties of ambipolar semiconductors.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Understanding organic materials performance in field-effect transistors

Comunicación oralIn the last years, much of our effort has been devoted to the search and study of new high-mobility semiconductors for organic thin film transistors. The approach used for the materials design has been two-fold: (i) the combination of donor and acceptor moieties in the pi-conjugated skeleton, which allows fine tuning of the frontier molecular orbitals, being this necessary for achieving electron/hole or ambipolar transport and ambient stability; and (ii) rational selection of the type and positioning of specific solubilizing substituents ensuring processability, which is essential to make these materials scalable to industry. However, material processability should be attained minimizing a negative effect on charge transport. Therefore, proper energy levels, planar molecular conformations, close intermolecular pi-pi stacking and adequate thin film crystallinity need to be maintained upon alkyl substitution. In this communication, several examples of molecular and polymeric materials are shown. A rational design, guided by experimental and theoretical evidences, has prompted modifications on their conjugated skeletons, donor/acceptor subunits ratio and/or selection of proper alkyl solubilizing chains, which induce noticeable changes in their electronic performances. The main aim of these studies is the basic understanding of charge transport in organic materials. For this end, we will use Raman spectroscopy and DFT quantum-chemical calculations as important tools for materials characterization.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

On some strategies using auxiliary information for estimating finite population mean

This paper presents an empirical investigation of the performance of five strategies for estimating the finite population mean using parameters such as mean or variance or both of an auxiliary variable. The criteria used for the choices of these strategies are bias, efficiency and approach to normality (asymmetry)

La información escrita del farmacéutico mejora el cumplimiento de la antibioterapia

Non-compliance with therapeutic guidelines represents a potential public health risk, given that it contributes to bacterialresistance. One of the strategies used to improve compliance to such guidelines is to provide the patient with betterinformation in written form. The objectives of the present investigation were the following; To evaluate the influencethat written information, provided by the community pharmacist, has on compliance with antibiotic therapy, to verify theconsequences of degree of compliance on patient health, and to discover other factors influencing patient compliance.The experimental study was carried on patients that attend a community pharmacy for antibiotic prescriptions. Membersof the control group were given information in verbal form only, while members of the experimental group were giventhe same information in both verbal and written form. The degree of compliance was determined through telephoneinterviews, carried out the day after having finished treatment. 214 patients completed the study. A 14% increase incompliance among members of the experimental group was achieved. Patients that had completed treatment, had a betterperception of their own health than those that had not. Another factor found to have a significant influence oncompliance was the number of daily dosages.In conclusion, the written information provided by the pharmacist improves therapeutic compliance. Therapeutic complianceimproves patients’ perception of their state of health. The number of daily dosages also have an influence to bear, butcontradict appropriate antibiotic administration policies.El incumplimiento terapéutico es un riesgo potencial para la salud pública al contribuir al incremento de lasresistencias bacterianas. Una de las estrategias utilizadas para mejorar el cumplimiento terapéutico es el de mejorarla información del paciente mediante información escrita. Los objetivos fueron evaluar la influencia de la informaciónescrita del farmacéutico comunitario sobre el cumplimiento antibiótico, verificar sus consecuencias sobre lasalud y descubrir otros factores que influyan en el cumplimiento. Se trata de un estudio experimental en pacientesque acuden a una farmacia comunitaria con una prescripción antibiótica. Al grupo control se le da informaciónverbal sobre su tratamiento, y al grupo de intervención la misma información, pero también por escrito. Se mideel cumplimiento mediante encuesta telefónica al día siguiente de haber tenido que finalizar el tratamiento. 214pacientes finalizaron el estudio. Los pacientes del grupo de intervención incrementaron el cumplimiento terapéuticoen un 14,2%. Los pacientes que cumplen el tratamiento tienen una mejor percepción de salud respecto de losincumplidores. Otro factor que influye significativamente en el cumplimiento es la pauta posológica diaria. Estetrabajo concluye que la información escrita del farmacéutico mejora el cumplimiento terapéutico. El cumplimientoterapéutico mejora la percepción de salud de los pacientes

Socio-economic benefits of weather and climate services in Europe

There is a rising interest around the world for a better understanding of the economic and social value added of weather services. National hydro-meteorological services and international cooperative bodies in meteorology have ever more to justify their use of public budgets. Furthermore, the development of hydrological and meteorological services is to a large extent steered by expectations regarding the eventual benefits of the envisaged new developments. This article provides a compact overview of the impediments for uptake of socio-economic benefit (SEB) studies, methods and results of SEB studies to date. It also discusses some pitfalls and crucial steps to enhance a broader uptake of SEB studies