A detailed investigation of the effect of hole transport material (HTM) pore filling on the photovoltaic performance of solid‐state dye‐sensitized solar cells (ss‐DSCs) and the specific mechanisms involved is reported. It is demonstrated that the efficiency and photovoltaic characteristics of ss‐DSCs improve with the pore filling fraction (PFF) of the HTM, 2,2’,7,7’‐tetrakis‐(N, N ‐di‐ p ‐methoxyphenylamine)9,9’‐spirobifluorene(spiro‐OMeTAD). The mechanisms through which the improvement of photovoltaic characteristics takes place were studied with transient absorption spectroscopy and transient photovoltage/photocurrent measurements. It is shown that as the spiro‐OMeTAD PFF is increased from 26% to 65%, there is a higher hole injection efficiency from dye cations to spiro‐OMeTAD because more dye molecules are covered with spiro‐OMeTAD, an order‐of‐magnitude slower recombination rate because holes can diffuse further away from the dye/HTM interface, and a 50% higher ambipolar diffusion coefficient due to an improved percolation network. Device simulations predict that if 100% PFF could be achieved for thicker devices, the efficiency of ss‐DSCs using a conventional ruthenium‐dye would increase by 25% beyond its current value.

We report a pump−probe spectroscopy study of electron injection rates in dye-sensitized solar cell (DSSC) devices. We examine the case of working devices employing an N719 ruthenium sensitizer and an iodide electrolyte. Electron injection is found to occur mainly on a sub-100 fs time scale, followed by a slower component with a lifetime of 26.9 ps, in accordance with previous reports on model samples. The amplitude of this latter component varies with electrolyte composition from 25 to 9%. The appearance of slower components in the electron injection dynamics may be attributed to an aggregated or weakly bound state of the surface-adsorbed N719 sensitizer. Further measurements are reported varying the cell light bias and load conditions, revealing no influence on electron injection dynamics. No other electron injection event is found to occur up to 1 ns. These results show no evidence for a slowdown of electron injection under working conditions compared to model systems for the electrolytes examined in this study. SECTION: Kinetics and Dynamics D ye-sensitized solar cells (DSSCs) can efficiently convert solar radiation into electricity by means of a molecular or quantum dot light harvester anchored on a wide-band-gap mesoporous semiconductor film. Electron injection from the photoexcited light harvester into the conduction band of the semiconductor, typically TiO 2 , is the first reaction in the photoconversion process.

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Conjugated organic polymers, small molecules, and transition metal organometallic complexes are used as active semiconducting materials in electronic and optoelectronic devices including organic solar cells (OSCs), organic field effect transistors (OFETS), organic light emitting diodes (OLEDs). While some of these technologies are mature and already available on the market, research is still very active in academic and industrial laboratories to gain better performances. Major drawbacks which still limit large industrial production of some of these devices are not only the non‐optimized performances, but also stability issues and cost. In fact, wide applicability of organic electronic technology largely relies on the development of efficient, durable and cost‐effective materials. Properties of molecular and polymeric semiconductors can be properly engineered and finely tuned by the design of the conjugated molecular structure and the selective introduction of various functional groups as substituents. Selective functionalization of the conjugated backbone with fluorine atoms and fluorinated substituents has been largely demonstrated to be an effective structural modification not only for tuning optoelectronic properties, but also to affect solid state organization and to improve stability. This review covers the most important classes of materials (conjugated polymers, small molecules, and organometallic complexes) reporting for each of these classes the applications in OSCs, OFETs, and OLEDs and highlighting the role of fluorine functionalization on the properties. The literature shows intriguing results that can be achieved by fluorine functionalization, and it also points out that this research field is still promising for future progress.

Direct arylation of 5-octylthieno[3,4-c]pyrrole-4,6-dione with a series of functionalized aryl iodides via C-H bond activation is demonstrated in a deep eutectic solvent made of choline chloride and urea in non-anhydrous conditions and without exclusion of air. This is the first demonstration of a thiophene-aryl coupling via direct arylation in deep eutectic solvents.

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This is the peer reviewed version of the following article: Photonics and optoelectronics with bacteria: making materials from photosynthetic microorganisms (Adv. Funct. Mater. 2019, 1805521), which has been published in final form at https://doi.org/10.1002/adfm.201805521. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditionsfor Use of Self-Archived Versions.

Direct arylation of thienopyrrolodione, diketopyrrolopyrroles, benzodithiophene derivatives, and fluorinated heteroarenes with functionalized aryl iodides is proven in solvent-free and non-anhydrous conditions. The reaction is performed in the presence of air and tolerates several functional groups on both the coupling partners, enabling a convenient synthesis of extended heteroaromatic conjugated molecules.