Molecular structure-device performance relationship in polymer solar cells based on indene-C60 bis-adduct derivatives

Abstract

Interfacial tension between two materials is a key parameter in determining their miscibility and, thus, their morphological behavior in blend films. In bulk heterojunction (BHJ)-type polymer solar cells (PSCs), control of the interfacial tension between the electron donor and the electron acceptor is critically important in order to increase miscibility and achieve optimized BHJ morphology for producing efficient exciton dissociation and charge transport. Herein, we report the synthesis of a series of indene-C 60 bis-adducts (ICBA) derivatives by modifying their end-groups with fluorine (FICBA), methoxy (MICBA) and bromine (BICBA) functional units. We systematically studied the effects of their structural changes on the blend morphology with poly(3-hexylthiophene) (P3HT) and their performance in the PSCs. The end-group modification of ICBA derivatives induced a dramatic change in their interfacial tensions with P3HT (i.e., from 4.9 to 8.3 mN m −1 ), resulting in large variations in the power conversion efficiency (PCE) of the PSCs, ranging from 2.9 to 5.2%.

Improving Photovoltaic Properties of P3HT:IC60BA through the Incorporation of Small Molecules

“…The literature suggests that the surface tension of P3HT is much lower than that of IC 60 BA. These two factors are in accordance with the predominance of fullerene (IC 60 BA) rich phase at the P3HT:IC 60 BA:DHP surface [48]. The increased contact angle of the P3HT:IC 60 BA:DHP confirms the improved hydrophobicity and re-distributions of the polymer and fullerene components in the ternary blended film.…”

Block copolymer compatibilized polymer: fullerene blend morphology and properties

“…As a result of high surface tension the mixing kinetics of P3HT/FFNCPF and P3HT/NCPF will be different and we expect large scale phase separation and FFNCPF to form large aggregates. Similar phenomenon has been reported by Cho et al [34] Our optical images support this behavior because large aggregates are seen in P3HT/FFNCPF blend (data not shown) while P3HT/NCPF films remain homogenous. (see ref 27).…”

Synergistic Effects of Terpolymer Regioregularity on the Performance of All-Polymer Solar Cells

“…The S value of the RR-(D 1 –A–D 2 –A): P A blend (1.08) is lower than those of the D 1 –A: P A blend (1.33) and Ra-(D 1 –A–D 2 –A): P A blend (1.33), suggesting that monomolecular recombinations in the RR-(D 1 –A–D 2 –A): P A blend are significantly more inhibited. These beneficial features in the RR-(D 1 –A–D 2 –A)-based all-PSC device can be mainly attributed to the better charge transport capability and stronger crystalline behavior, resulting in the enhanced J sc and FF values. − …”