New Bithiazole‐Based Sensitizers for Efficient and Stable Dye‐Sensitized Solar Cells

Abstract

A series of new push-pull organic dyes (BT-I-VI), incorporating electron-withdrawing bithiazole with a thiophene, furan, benzene, or cyano moiety, as π spacer have been synthesized, characterized, and used as the sensitizers for dye-sensitized solar cells (DSSCs). In comparison with the model compound T1, these dyes containing a thiophene moiety between triphenylamine and bithiazole display enhanced spectral responses in the red portion of the solar spectrum. Electrochemical measurement data indicate that the HOMO and LUMO energy levels can be tuned by introducing different π spacers between the bithiazole moiety and cyanoacrylic acid acceptor. The incorporation of bithiazole substituted with two hexyl groups is highly beneficial to prevent close π-π aggregation, thus favorably suppressing charge recombination and intermolecular interaction. The overall conversion efficiencies of DSSCs based on bithiazole dyes are in the range of 3.58 to 7.51 %, in which BT-I-based DSSCs showed the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 81.1 %, a short-circuit photocurrent density (J(sc)) of 15.69 mA cm(-2), an open-circuit photovoltage (V(oc)) of 778 mV, and a fill factor (ff) of 0.61, which correspond to an overall conversion efficiency of 7.51 % under standard global AM 1.5 solar light conditions. Most importantly, long-term stability of the BT-I-III-based DSSCs with ionic-liquid electrolytes under 1000 h of light soaking was demonstrated and BT-II with a furan moiety exhibited better photovoltaic performance of up to 5.75 % power conversion efficiency.

Synthesis, Electrochemistry, Crystal Structures, and Optical Properties of Quinoline Derivatives with a 2,2′‐Bithiophene Motif

“…We found that 2-aminoacetophenone (1a) could be easily converted into quinoline 3a within two hours by using 1 mol-% [Ru 3 (CO) 12 ] and 3 mol-% HBF 4 . In the case of compound 3b and 3c, the use of 0.5 mol-% [Ru 3 (CO) 12 ] and 1.5 mol-% HBF 4 was optimal to obtain the desired compounds in moderate yield (50-63 %). It is worth mentioning that extending the reaction time or increasing catalyst loading, even up to 10 mol-%, did not raise the efficiency of the reaction.…”

“…[2] In addition, they have drawn attention for their application in bioanalytics as fluorescent sensors. [3,4] Besides their unquestionable medicinal properties, quinolines, and especially their substituted derivatives, are of major interest for their application in optoelectronic and organic electronics. [5][6][7][8] For the past few years, various quinoline derivatives have been used as ligands for transition-metal complexes, [9][10][11] which have found wide application in organic light-emitting diodes (OLEDs) [7,9,[12][13][14][15] and organic photovoltaics.…”

Effect of Thiophene in Bithiazole-Bridged Sensitizers on the Performance of Dye-Sensitized Solar Cells

“…[24][25][26] The synthesis of TBT-T3 are depicted in Scheme 2. The Suzuki coupling reaction of compound 1 with (4-(p-tolyl)-1, 2, 3, 3a, 4, 8b-hexahydrocyclopenta [b]indol-7-yl)-boronic acid produced compound 2.…”

“…In 2009, Li's research group reported that organic photovoltaics based on bithiazole copolymers achieved power conversion e±ciency of 3.0% with J sc ¼ 8:0 mAcm À2 and V oc ¼ 0:70 V. 23 In our previous studies, we designed and synthesized a series of bithiazole-bridged sensitizers. [24][25][26] High-performance and long-term stability were achieved. In this paper, we developed our research and investigated the e®ect of thiophene in bithiazole-bridged dyes: BT-T2, TBT-T2, BT-T3 and TBT-T3 (see Scheme 1) on the performance of DSSCs, in which two most common donors, triphenylamine and indoline, were adopted for comparison.…”

Metal‐Free Sensitizers Containing Hydantoin Acceptor as High Performance Anchoring Group for Dye‐Sensitized Solar Cells

“…The organic sensitizers based on donor-auxiliary acceptor-π-acceptor (D-A-π-A) have been widely explored in solar energy conversion applications. [2][3][4][5] Indeed, these organic sensitizers have demonstrated excellent light-harvesting ability and power-conversion efficiency (PCEs) of more than 12%. [6][7][8] Until now, the most widely used donor groups for DSSCs are based on triphenylamine and its derivatives, due to their for the first time as anchoring and acceptor group for DSSCs.…”