Improvement in Power Conversion Efficiency and Performance of P3HT/PCBM Solar Cells Using Dithiafulvalene‐Based π‐Conjugated Oligomers

Abstract

The improvement in the power conversion efficiency (PCE) and performance of poly(3‐hexylthiophene) (P3HT)/[6,6]‐phenyl‐C61butyric acid methyl ester (PCBM) solar cells are reported by using dithiafulvalene (DTF)‐based conjugated oligomers ((poly[2‐(9H‐fluoren‐9‐ylidene)‐4,5‐bis(hexylthio)‐1,3‐dithiole‐ran‐(2,1,3‐benzothiadiazole)] (PTBT) and poly[2,7‐(9,9‐dihexyl­fluorene)‐ran‐(2‐(9H‐fluoren‐9‐ylidene)‐4,5‐bis(hexylthio)‐1,3dithiole]‐ran‐(2,1,3‐benzothiadiazole)] (PFTBT)) that contain a DTF unit, which serves as an electron‐rich donor, and a benzothiadiazole group, which serves as an electron‐deficient acceptor in the main chain. A P3HT/PCBM device with 5 wt% PTBT exhibits an efficiency of up to 1.78%, which is higher than that of a device composed only of a P3HT/PCBM blend (1.01%). Introducing 2 wt% PTBT into the P3HT/PCBM blend substantially increases the charge‐carrier mobility from 2.01 × 10−4 to 4.59 × 10−4 cm2 V−1s−1. The improvement of the PCE is attributed to improved charge transport in the device and an increased open‐circuit voltage, suggesting that blending PTBT increases the intermolecular interaction of the molecules. In addition, doping the oligomer in ambient atmospheric conditions enhances the stability of these devices.

Ternary miscibility with specific interactions in novel blends comprising biodegradable polymers and a natural polyphenol

“…These polymers are widely applied in the daily life and investigated [1][2][3][4][5][6]. For example, they can be used in packing, electrical products, and composites [7][8][9][10][11][12].…”