Fine-Tuning by Triple Bond of Carbazole Derivative Dyes to Obtain High Efficiency for Dye-Sensitized Solar Cells with Copper Electrolyte

Abstract

Three novel dyes consisting of a 5,8,15-tris(2-ethylhexyl)-8,15dihydro-5H-benzo [1,2-b:3,4-b′:6,5-b″]tricarbazole (BTC) electron-donating group and a 4,7-bis(4-hexylthiophen-2-yl)benzo [c][1,2,5]thiadiazole (BTBT) π-bridge with an anchoring group of phenyl carboxyl acid were synthesized and applied in dye-sensitized solar cells (DSCs).The AJ202 did not contain any triple bonds, the AJ201's ethynyl group was inserted between the BTC and BTBT units, and the AJ206's ethynyl group was introduced between the BTBT moiety and the anchor group. The inclusion and position of the ethynyl linkage in the sensitizer molecules significantly altered the electrochemical properties of these dyes, which can fine-tune the energy levels of the dyes. The best performing devices contained AJ206 as a sensitizer and a Cu(I/II) redox couple, which resulted in a power conversion efficiency (PCE) up to 10.8% under the standard AM 1.5 G illumination, which obtained PCEs higher than those from the devices that contained AJ201 (9.2%) and AJ202 (9.7%) under the same conditions. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels of the sensitizers were tuned to be well-suited for the Cu(I/II) redox potential and the Fermi level of TiO 2 . The innovative synthesis of a tricarbazole-based donor moiety in a sensitizer used in combination with a Cu(I/II) redox couple has resulted in relatively high PCEs.

Solar energy conversion using first row d-block metal coordination compound sensitizers and redox mediators

“…Over the 2020-2021 period, the number of publications focusing on DSCs which combine organic or zinc(II) porphyrin dyes with Cu 2+ /Cu + redox shuttles has increased signicantly, [127][128][129][130][131][132][133][134][135][136][137] with some record breaking DSC performances were also fabricated. In keeping with the more positive redox potentials of the copper-containing redox mediators, DSCs with the latter out-performed those with the cobalt-based couples.…”

“…Over the 2020–2021 period, the number of publications focusing on DSCs which combine organic or zinc( ii ) porphyrin dyes with Cu 2+ /Cu + redox shuttles has increased significantly, 127–137 with some record breaking DSC performances originating in extremely high V OC values. Colombo et al recently reviewed the field.…”

Structures, Properties, and Device Applications for [1]Benzothieno[3,2‐b]Benzothiophene Derivatives

“…Therefore, the BTBT derivatives have been extensively utilized in OFETs, photodetectors, synaptic devices, solar cells, and light emitting devices. [174][175][176][177][178][179] BTBT-based electronic and optoelectronic devices will be described as below.…”

Branched Methoxydiphenylamine-Substituted Carbazole Derivatives for Efficient Perovskite Solar Cells: Bigger Is Not Always Better

“… 17 , 18 Therefore, carbazole-based derivatives have been employed in organic light-emitting diodes 19 , 20 and dye-sensitized solar cells. 21 − 23 In recent years, carbazole has also attracted much attention in PSCs. 24 − 29 …”