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AbstractThe synthesis and characterization of two related families of star‐shaped thiophene‐containing hole‐transporting materials (HTMs) based on fused tetrathienoanthracene and nonfused tetrathienylbenzene cores are reported. All of them are endowed with four terminal (4,4′‐dimethoxy)diphenylamino groups that are either linked directly to the core or showed a different type of bridges (i.e., thiophene‐phenyl or phenyl rings). The novel HTMs are tested in mixed‐ion perovskite (Cs0.1FA0.74MA0.13PbI2.48Br0.39) solar cells, and power conversion efficiencies of up to 18.8% are measured under 1 sun irradiation, comparable with the efficiency obtained for the reference cell using 2,2′,7,7′‐tetrakis(N,N′‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene as an HTM.

Two ruthenium sensitizers TT-230 and TT-232 based on cyclopenta[2,1-b:3,4-b']dithiophene (CDT) were tested in dye-sensitized solar cells (DSSCs) using,a tri-iodide/iodide redox couple, and their performances compared to the benchmark Z907. Both dyes of general formula Ru(LL')(NCS)(2) feature the same 4.4'-dicarboxylic acid 2,2'-bipyridine moiety acting as the anchoring group (L) to attach the dye on the TiO2 surface, and two CDT subunits as ancillary groups (L' either directly-linked (11-230) or vinylene-linked (TT-232) to the bipyridine moiety. In comparison with TT-230, the it-extended conjugation in TT-232 caused significant redshift and broadening of the absorption bands. However, despite better light-harvesting properties, the DSSC device sensitized with TT-232 strikingly underperformed compared to TT-230 under same conditions (PCE = 3.2% and 6.1%, respectively). The use of co-adsorbent (CHENO) or surfactants did not help to improve the photovoltaic properties of TT-230, and resulted in a degradation of the overall efficiency of the cell. (C) 2014 Elsevier Ltd. All rights reserved.