A Soluble Ladder‐Conjugated Star‐Shaped Oligomer Composed of Four Perylene Diimide Branches and a Fluorene Core: Synthesis and Properties. Issue 32 (26th June 2014)

• Record Type: Journal Article
• Authors: Zhang, Youdi; Chen, Lingcheng; Zhang, Kaichen; Wang, Helin; Xiao, Yi
• Is Part Of: Chemistry. Volume 20:Issue 32(2014)
• Page Start: 10170
• Page End: 10178
• Publication Date: 2014-06-26
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201402100
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A new ladder‐conjugated star‐shaped oligomer electron‐transporting material <bold>TetraPDI‐PF</bold>, with four perylene diimide (PDI) branches and a fluorene core, was efficiently synthesized. The oligomer is highly soluble in dichlorobenzene with a solubility of 155 mg mL<sup>−1</sup>, which is higher than those of PDI (35 mg mL<sup>−1</sup>) and <bold>PDI‐Phen</bold> (70 mg mL<sup>−1</sup>). Demonstrated by thermogravimetric analysis (TGA), the oligomer exhibits excellent thermal stability with the decomposition temperature (<italic>T</italic><sub>d</sub>) of 291.2 °C, which is 65 °C higher than that of PDI. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed to investigate the electrochemical properties. Although the CV curves of <bold>TetraPDI‐PF</bold> are successively scanned for 15 cycles, they still remain invariable reduction potentials. The oligomer also shows outstanding photostability, even better than PDI, which maintains 99 % fluorescence intensity after irradiation for 10 min using maximum laser intensity. In the steady‐state space‐charge‐limited current (SCLC) devices, <bold>TetraPDI‐PF</bold> exhibits higher intrinsic electron mobility of 2.22×10<sup>−5</sup> cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup>, three orders of magnitude over that of PDI (3.52×10<sup>−8</sup> cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup>). The bulk heterojunction (BHJ) organic solar cells (OSCs) using <bold>TetraPDI‐PF</bold> as non‐fullerene acceptors and P3HT as donors give optimum power conversion efficiency (PCE) of 0.64 %, which is 64 times that of the PDI:P3HT BHJ cells.</p> </abstract>