Benzo[a]carbazole-Based Donor−π–Acceptor Type Organic Dyes for Highly Efficient Dye-Sensitized Solar Cells

Abstract

A novel class of metal-free organic dyes based on benzo[a]carbazole have been designed, synthesized, and used in dye-sensitized solar cells for the first time. These types of dyes consisted of a cyanoacrylic acid moiety as the electron acceptor/anchoring group and different electron-rich spacers such as thiophene (JY21), furan (JY22), and oligothiophene (JY23) as the π-linkers. The photophysical, electrochemical, and photovoltaic properties, as well as theoretical calculations of these dyes were investigated. The photovoltaic performances of these dyes were found to be highly relevant to the π-conjugated linkers. In particular, dye JY23 exhibited a broad IPCE response with a photocurrent signal up to about 740 nm covering the most region of the UV-visible light. A DSSC based on JY23 showed the best photovoltaic performance with a Jsc of 14.8 mA cm(-2), a Voc of 744 mV, and a FF of 0.68, achieving a power conversion efficiency of 7.54% under standard AM 1.5 G irradiation.

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

“…Upon chromatography (9-hexylcarbazole-3-yl)boronic acid pinacol ester (5) was obtained as a liquid in good yield. (9-Hexylcarbazole-3-yl)boronic acid pinacol ester (5) was subjected to Suzuki-Miyaura reaction either with 2-bromopyridine-4-carbaldehyde (6a) or 2-bromopyridine-5carbaldehyde (6b) in the presence of potassium carbonate and bis(triphenylphosphine)palladium(II) dichloride in tetrahydrofuran [2]. Upon repeated purification by chromatography, compounds 7a and 7b were obtained as liquids in good yields (Scheme 1).…”

“…Carbazole derivatives have found many different applications in a variety of technologically important areas, such as organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), dye synthesised solar cells (DSSCs) and sensors [1,2]. In OLEDs, carbazole derivatives are frequently used as host materials [3][4][5].…”

“…It is therefore essential that one should design a molecule that has multifunctional usage in many different areas of technology [24]. Since carbazole is a relatively inexpensive material with unique properties such as high hole-transporting mobility [12,[25][26][27], pronounced thermal stability [2] and high fluorescent quantum yields [28,29] our attention was focused on carbazole derivatives. In addition to that, carbazole is a rigid ar-omatic molecule [30] with many different modification sites for multifunctionalisation [31].…”

Size-controllable synthesis of NiCoSe2 microspheres as a counter electrode for dye-sensitized solar cells

“…A smaller value of R ct stands for a smaller value of the overpotential needed for the electron transfer from CE to electrolyte. 32,33 The low-frequency semicircle (right-hand side) represents the Warburg diffusion resistance (ZW) within the bulk electrolyte and the electrocatalyst lm. The abovementioned parameters were extracted by tting the EIS spectrum with an equivalent circuit (the inset of Fig.…”

Effects of structural optimization on the performance of dye-sensitized solar cells: spirobifluorene as a promising building block to enhance Voc

“…9 A complete DSSC is made of photoanode, sensitizer, electrolyte and counter electrode. [20][21][22] Through the continuous efforts and exploration of the researchers, many new frameworks such as D-D-π-A, D-π-A-π-A, D-π-(A) n and D-A-π-A have been explored. D-π-A (donor-π-acceptor) is the most common framework for efficient dyes.…”