[en] The production of energy taking into account the current environmental context and future climate concerns is a major research topic to which the scientific community that studies polymers can and must contribute greatly. This paper presents examples of applications of photo- and electro-active polymers for the production of photovoltaic energy, thermoelectricity and refrigeration

[en] Luminescent organic phases embedded in conductive inorganic matrices are proposed for hybrid organic-inorganic light-emitting diodes. In this configuration, the organic dye acts as the radiative recombination site for charge carriers injected into the inorganic matrix. Our investigation is aimed at finding a material combination where the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the organic dye are situated in between the valence and conduction bands of the inorganic matrix in order to promote electron and hole transfer from the matrix to the dye. Bilayer and composite thin films of zinc selenide (ZnSe) and a red iridium complex (Ir(BPA)) organic light emitter were prepared in situ via UHV thermal evaporation technique. The electronic and atomic structures were studied applying X-ray and ultraviolet photoelectron spectroscopies. The measured energy band alignments for the ZnSe/Ir(BPA) bilayer and ZnSe+Ir(BPA) composite reveal that the HOMO and LUMO of the organic dye are positioned in the ZnSe bandgap. For the initial steps of ZnSe deposition on a dye film to form Ir(BPA)/ZnSe bilayers, zinc atoms intercalate into the dye film leaving behind an excess of selenium at the interface that partly reacts with dye molecules. Photoelectron spectroscopy of the composites shows the same species suggesting a similar mechanism. This mechanism leads to composite films with increased content of amorphous phases in the inorganic matrix, thereby affecting its conductivity, as well as to the presence of nonradiative recombination sites provided by the intercalated Zn atoms

[en] Highlights: • The optical properties of 12 donor/acceptor copolymers are predicted using TDDFT. • A full rationalization with respect to the nature of the D/A pair is provided. • The CPDTDPP polymer exhibits the highest light harvesting properties. • The stabilized LUMO of CPDTDPP with respect to PCBM limits its potential for OPV. • CPDTBT emerges as a better compromise for solar cell applications. TDDFT calculations are associated to an extrapolation scheme to predict the optical properties of twelve donor-acceptor copolymers, in which carbazole, benzodithiophene or cyclopentadithiophene donor subunits are combined to benzofurazane, benzothiadiazole or diketopyrrolopyrrole acceptor moieties. Relative excitation energies and absorption strengths are rationalized in terms of geometrical, electronic and optical descriptors. It is shown that the combination of a cyclopentadithiophene with a diketopyrrolopyrrole leads to the lowest excitation energy and highest light absorption efficiency within the series. However, combining cyclopentadithiophene and benzodithiophene subunits appears as more efficient for solar cell applications due to better energy level alignment with respect to PCBM.

[en] Proposed by representatives of the main involved companies, agencies and institutions, the contributions of this colloquium addressed the following issues: the role of new energy technologies in the French and World sustainable development; The programmes 'New energy technologies'; Research priorities for these new technologies; Industry Perspectives and challenges; SMEs and the ANR; Research perspectives and challenges (electrochemical storage of energy, solar photovoltaic energy, new materials for energy, integration of renewable energies in electric systems, technological innovations for new energy technologies)