Thermoelectrics have emerged as a strategy for solar‐to‐electricity conversion, as they can complement photovoltaic devices as IR harvesters or operate as stand‐alone systems often under strong light and heat concentration. Inspired by the recent success of inorganic‐based solar thermoelectric generators (STEGs), in this manuscript, the potential of benchmark organic thermoelectric materials for solar harvesting is evaluated. It is shown that the inherent properties of organic semiconductors allow the possibility of fabricating organic STEGs (SOTEGs) of extraordinary simplicity. The broadband light absorption exhibited by most organic thermoelectrics combined with their low thermal conductivities results in a significant temperature rise upon illumination as seen by IR thermography. Under 2 sun illumination, a temperature difference of 50 K establishes between the illuminated and the non‐illuminated sides of a poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) film, and ≈40 K for a carbon nanotube/cellulose composite. Moreover, when using light as a heat source, the Seebeck coefficient remains unaffected, while a small photoconductivity effect is observed in PEDOT:PSS and carbon nanotubes. Then, the effect of several geometrical factors on the power output of a solar organic thermoelectric generator is investigated, enabling us to propose simple SOTEG geometries that capitalize on the planar geometry typical of solution‐processable materials. Finally, a proof‐of‐concept SOTEG is demonstrated, generating 180 nW under 2 suns.

Organometallic coordination polymers (OMCPs) are a promising class of thermoelectric materials with high electrical conductivities and thermal resistivities. The design criteria for these materials, however, remain elusive and so far material modifications have been focused primarily on the nature of the metal cation to tune the thermoelectric properties. Herein, an alternative approach is described by synthesizing new organic ligands for OMCPs, allowing modulation of the thermoelectric properties of the novel OMCP materials over several orders of magnitude, as well as controlling the polarity of the Seebeck coefficient. Extensive material purification combined with spectroscopy experiments and calculations furthermore reveal the charge‐neutral character of the polymer backbones. In the absence of counter‐cations, the OMCP backbones are composed of air‐stable, ligand‐centered radicals. The findings open up new synthetic possibilities for OMCPs by removing structural constraints and putting significant emphasis on the molecular structure of the organic ligands in OMCP materials to tune their thermoelectric properties.

Heteroleptic ruthenium (II) complexes were used for sensitizing ZnO surfaces in organic solar cells (OSCs) as mediators with photoactive layers. The complexes [Ru(4,4′-X 2 -bpy)(Mebpy-CN) 2 ] 2+ (with X = −CH 3 , −OCH 3 and −N(CH 3 ) 2 ; bpy = 2,2′-bipyridine; Mebpy-CN = 4-methyl-2,2′-bipyridine-4′-carbonitrile) were synthesized and studied by analytical and spectroscopical techniques. Spectroscopic, photophysical, and electrochemical properties were tuned by changing the electron-donating ability of the -X substituents at the 4,4′-positions of the bpy ring and rationalized by quantum mechanical calculations. These complexes were attached through nitrile groups to ZnO as interfacial layer in an OSC device with a PBDB-T:ITIC photoactive layer. This modified inorganic electron transport layer generates enhancement in photoconversion of the solar cells, reaching up to a 23% increase with respect to the unsensitized OSCs. The introduction of these dyes suppresses some degradative reactions of the nonfullerene acceptor due to the photocatalytic activity of zinc oxide, which was maintained stable for about 11 months. Improving OSC efficiencies and stabilities can thus be achieved by a judicious combination of new inorganic and organic materials.

A set of o-carborane appended π-conjugated fluorophores and their light-emitting properties in solid state are reported. The aggregation-induced emission enhancement (AIEE) exhibited for one of the fluorenyl derivatives paved the...