Publication Date:
2015-06-11
Description:
Polymer solar cells (PSCs) based on aliphatic-amino-functionalized materials presented low performance with negligibly small efficiency, the prime mechanism of which is found to be hole trapping induced by the amine end groups. We propose that such hole trapping behavior depends on the relative energetic position of the hole transport states and the trapping states. Herein, we comparatively study the photovoltaic properties of PSCs based on amino-functionalized fullerene derivative blended with poly [N-9′-heptadecanyl-2, 7-carbazole-alt-5, 5-(4′, 7′-di-2-thienyl-2′, 1′, 3′-benzothiadiazole)] (PCDTBT) or poly (3-hexylthiophene) (P3HT). The former polymer has a lower-positioning highest occupied molecular orbital (HOMO) level, whereas the latter has a comparable HOMO level relative to the ionization state of tertiary aliphatic amine in energy. Our investigation confirms our proposition, revealing an ultrafast trapping process in PCDTBT:amino-group-functionalized fullerene derivative film, which seriously crippled hole transport, consequently results in very poor device performance. In contrast, trapping process is almost negligible in P3HT systems.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
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