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Abstract: The development of new anchoring groups is important to facilitate effective co‐sensitization in dye‐sensitized solar cells (DSSCs). Herein, stable organic D–π–A dyes that contain new heterocyclic hydantoin‐based anchoring groups have been designed, synthesized, and used in DSSCs. These dye sensitizers were evaluated in terms of their absorption spectra, electrochemical properties, and performance in DSSC devices. Although only one‐third of the amount of hydantoin‐containing dyes adsorbed onto TiO2 relative to their cyanoacrylic‐acid‐containing analogues, they exhibited effective photoexcited electron‐transfer properties. External quantum efficiencies of over 80 % was observed, which were comparable to those of the cyanoacrylic‐acid‐containing dyes. In addition, the new hydantoin‐containing dyes exhibited significant robustness, which could allow improved stability of their corresponding photovoltaic devices under harsh conditions, such as high temperature and humidity. [ABSTRACT FROM AUTHOR]

Twenty-four D-A′-π-A dyes were rapidly synthesized through a one-pot three-component Suzuki-Miyaura coupling reaction, which was assisted by microwave irradiation. We measured the absorption spectra, electrochemical properties, and solar-cell performance of all the synthesized dyes. The D5 πA4 dye contained our originally designed rigid and nonplanar donor and exerted the highest efficiency at 5.4 %. The short-circuit current ( Jsc) was the most important parameter for the conversion efficiency ( η) in the case of the organic D-A′-π-A dyes. Optimal ranges for the D-A′-π-A dyes were observed for high values of Jsc/ λmax at λ=560-620 nm, an optical-absorption edge of λ=690-790 nm, and EHOMO and ELUMO values of <1.14 and −0.56 to −0.76 V, respectively. [ABSTRACT FROM AUTHOR]

We demonstrate herein the divergent synthesis of six dyes containing our originally developed rigid and nonplanar donor with three different secondary electron donors (SEDs), namely thiophene, 4-methoxybenzene, and diphenylethene. Evaluation of the photophysical properties of the synthesized dyes revealed that the introduction of the SEDs resulted in an increased absorbance in the 350-450 nm region. The influence of the SEDs on the electrochemical and photovoltaic properties depended on their structure and position of attachment. The introduction of the thiophene SED to D4π4A2, which we previously reported to be our best dye, resulted in an increased Jsc. The dye-sensitized solar cell (DSSC) prepared by using dye 2b, which contains the thiophene SED, shows a higher power conversion efficiency (PCE; η = 4.62 ± 0.02 %) and a higher incident photon-to-current conversion efficiency (IPCE) in the region 300-600 nm than D4π4A2. [ABSTRACT FROM AUTHOR]

Quasi-solid dye-sensitized solar cells (QDSCs) consisting of amylose/porous Al2O3 film/ionic liquid films (Am-Al/IL film) are reported. The surface of straight nanopores in the Al2O3 film was modified with amylose and these nanopores were filled with ionic-liquid-type electrolytes. The ionic liquid did not leak from these nanopores of the film. The photovoltaic performance of the QDSC consisting of Am-Al/IL films was almost the same as that before the solidification, despite that the film was occupied with 50% of electrochemically inactive Al2O3 wall. It was found that the iodine was adsorbed on the straight wall of Am—Al films and the apparent diffusion coefficient of I3- species was almost the same as that in the parent liquid electrolyte. From these results and our previous reports, we propose QDSC structures consisting of two-carrier-density layers (I-/I3-) with low and high carrier concentrations for high-efficiency cells. A bulk area between a counter electrode and a TiO2 electrode is occupied with a high-carrier-density medium (I-/I3-), and TiO2 nanopores are filled with a low-carrier-density medium (I-/I3-). The former increases the conductivity and the latter suppresses the back electron transfer from the TiO2 layer to redox species. [ABSTRACT FROM AUTHOR]