Search

High‐performance organic solar cells are deposited from eco‐friendly semiconductor dispersions by applying reversible electrostatic stabilization while omitting the need for stabilizing surfactants. The addition of iodine fosters the oxidation (p‐doping) of the light‐harvesting polymer, effectively promoting the electrostatic repulsion of the nanoparticles and hence the colloidal stability of the respective dispersions. The oxidation of polymers with iodine is reversible: after thin‐film deposition and after thermal evaporation of the iodine, the corresponding polymer:non‐fullerene solar cells yield power conversion efficiencies of up to 10.6%. [ABSTRACT FROM AUTHOR]

State‐of‐the‐art solvents for the fabrication of organic solar cells are mostly toxic or hazardous. First attempts to deposit light‐harvesting layers from aqueous or alcoholic nanoparticle dispersions instead have been successful on laboratory scale, enabling future eco‐friendly production of organic solar cells. In this work, a scalable high‐throughput continuous‐flow microfluidic system is employed to synthesize surfactant‐free organic semiconductor dispersions by nanoprecipitation. By adjusting the differential speed of the syringe pumps, the concentration of the initial solute and the irradiation of the microfluidic chip, the synthesis can be controlled for tailored dispersion concentrations and nanoparticle sizes. The resulting dispersions are highly reproducible, and the semiconductor inks are stable for at least one year. The synthesis of the dispersions is exemplified on a polymer/fullerene combination with large‐scale availability. [ABSTRACT FROM AUTHOR]

Organic semiconductor nanoparticle dispersions are electrostatically stabilized with the p‐doping agent 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ), omitting the need for surfactants. Smallest amounts of F4TCNQ stabilize poly(3‐hexylthiophene) dispersions and reduce the size of the nanoparticles significantly. The concept is then readily transferred to synthesize dispersions from a choice of light‐harvesting benzodithiophene‐based copolymers. Dispersions from the corresponding polymer:fullerene blends are used to fabricate organic solar cells (OSCs). In contrast to the widely used stabilizing surfactants, small amounts of F4TCNQ show no detrimental effect on the device performance. This concept paves the way for the eco‐friendly fabrication of OSCs from nanoparticle dispersions of high‐efficiency light‐harvesting semiconductors by eliminating environmentally hazardous solvents from the deposition process. [ABSTRACT FROM AUTHOR]

We report on solution-processed, semitransparent organic solar cells that are implemented as lenses in sunglasses. The electrical power provided by the lens-fitted solar cells sustains a microelectronic circuit that is used to read out temperature and illumination intensity sensors and to make this information available on two displays integrated into the temples of the 'Solar Glasses'. The microelectronic circuit is designed to operate at illumination intensities down to 500 lux, rendering the Solar Glasses suitable for outdoor and indoor use as well as for operation in diffuse light. Hence, this case study provides an example for consumer-oriented mobile applications, self-powered by integrated solar cells, which specifically exploit the unique properties of organic solar cells. [ABSTRACT FROM AUTHOR]

Solar Glasses: The clear view through lens‐fitted solar cells of smart glasses exemplifies the outstanding properties of organic solar cells. Their color, shape, and transparency can be tailored to match the specific requirements of self‐sustaining future mobile applications. Even under low light conditions, here down to 500 Lux, they still provide sufficient power output to operate a microcontroller and two liquid crystal displays integrated into the temples of the glasses. This work from Alexander Colsmann′s group at Karlsruhe Institute of Technology describes the Solar Glasses in detail and provides a fresh view on how organic solar cells may enable new applications. More details can be found in the Full Paper by Dominik Landerer et al. on page 1936 in Issue 11, 2017 (10.1002/ente.201700226). [ABSTRACT FROM AUTHOR]