Solar Energy Materials and Solar Cells, Vol.109, 33-39, 2013
Donor-acceptor small molecule with coplanar and rigid pi-bridge for efficient organic solar cells
A novel donor-acceptor (D-A) donor molecule, 1, comprising of two di-p-tolylamino donors and a dicyanovinylene acceptor bridged by a planar and rigid fluorene moiety has been synthesized and characterized. The molecular structure and crystal packing of 1 was characterized by single-crystal X-ray crystallography. Such molecular configuration endowed 1 with an efficient D-A interaction, rendering an intense ICT absorption band for efficiently light-harvesting and retain low-lying HOMO for generating sufficient open-circuit voltage (V-oc). The vacuum-deposited hybrid planar-mixed heterojunction (PMHJ) photovoltaic devices utilizing 1 as donor and C70 as acceptor to achieve power conversion efficiencies (PCEs) of 4.04 and 5.31% for the single- and tandem-cell photovoltaic devices under simulated AM 1.5 illumination (100 mW cm(-2)). (C) 2012 Elsevier B.V. All rights reserved.