Enhancing the Energy‐Conversion Efficiency of Solid‐State Dye‐Sensitized Solar Cells with a Charge‐Transfer Complex based on 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone

Abstract

As a champion hole‐transporting material (HTM), 2,2′7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (Spiro‐OMeTAD) has been widely used in solid‐state dye‐sensitized solar cells (ssDSCs). Owing to the low conductivity of Spiro‐OMeTAD, a chemical doping strategy is commonly used to enhance its hole‐transporting properties. In this study, we report a strong electron acceptor, 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) as an additive for Spiro‐OMeTAD along with its application in ssDSCs. We show that the conductivity of Spiro‐OMeTAD increases from 5.31×10−5 to 2.22×10−4 S cm upon the addition of 0.04 % DDQ, and the power conversion efficiency (PCE) of the ssDSCs also increases. By utilizing a donor–π–acceptor sensitizer with a high coefficient and an HTM with an optimized doping ratio, we were able to achieve a high PCE of 6.37 % for the ssDSCs under 100 mW cm−2 AM1.5G simulated illumination, in comparison to the PCE of the pristine device, which was only 3.50 %. An increase in the application of benzoquinone‐based materials for organic electronics is expected, especially for solar‐cell applications.

Strong electron acceptor additive based spiro-OMeTAD for high-performance and hysteresis-less planar perovskite solar cells

“…37 As the charge-transfer complex is generated, it would leave holes in spiro-OMeTAD and increase the electrical conductivity as well as hole mobility of nal HTL in devices for better photovoltaic performance. 41 Therefore, the doping mechanism may be described as follows:…”

Dye-sensitized solar cells strike back

“…Photovoltaic efficiencies improved from 3.50 to 6.37% when an small quantity of the dopant was introduced. 510 …”

The researcher's guide to solid-state dye-sensitized solar cells

“…The most recent work on p-dopants in ssDSCs was published by Sun and coworkers, who studied the effects on spiro-OMeTAD of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), another oxidant widely used in organic synthesis. 298 The most notable result of their work is that only a very tiny 0.04% DDQ addition to spiro-OMeTAD was required to maximize solar cell efficiency. Conductivity of the oxidized HTM film increased from 5.31 Â 10 À5 to 2.22 Â 10 À4 S cm À1 and the device efficiency was boosted from 3.50 to 6.37%.…”