Synthesis and Characterization of a Soluble A-D-A Molecule Containing a 2D Conjugated Selenophene-Based Side Group for Organic Solar Cells.
A new acceptor-donor-acceptor (A-D-A) small molecule based on benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) is synthesized via a Stille cross-coupling reaction. A highly conjugated selenophene-based side group is incorporated into each BDT unit to generate a 2D soluble small molecule (SeBDT-DPP). SeBDT-DPP thin films produce two distinct absorption peaks. The shorter wavelength absorption (400 nm) is attributed to the BDT units containing conjugated selenophene-based side groups, and the longer wavelength band is due to the intramolecular charge transfer between the BDT donor and the DPP acceptor. SeBDT-DPP thin films can harvest a broad solar spectrum covering the range 350-750 nm and have a low bandgap energy of 1.63 eV. Solution-processed field-effect transistors fabricated with this small molecule exhibit p-type organic thin film transistor characteristics, and the field-effect mobility of a SeBDT-DPP device is measured to be 2.3 × 10-3cm2V-1s-1. A small molecule solar cell device is prepared by using SeBDT-DPP as the active layer is found to exhibit a power conversion efficiency of 5.04% under AM 1.5 G (100 mW cm-2) conditions.
Department of Chemistry, The Catholic University of Korea, Bucheon-si, Gyeonggido, 420-743, Republic of Korea.
Yurim
Y
Shin
Energy Materials Research Center, Korea Research Institute of Chemical Technology, Daejeon, 305-600, Republic of Korea.
Chang Eun
CE
Song
Department of Chemistry, The Catholic University of Korea, Bucheon-si, Gyeonggido, 420-743, Republic of Korea.
Woo-Hyung
WH
Lee
Energy Materials Research Center, Korea Research Institute of Chemical Technology, Daejeon, 305-600, Republic of Korea.
Sang Kyu
SK
Lee
Energy Materials Research Center, Korea Research Institute of Chemical Technology, Daejeon, 305-600, Republic of Korea.
Won Suk
WS
Shin
Department of Chemistry, The Catholic University of Korea, Bucheon-si, Gyeonggido, 420-743, Republic of Korea.
In-Nam
IN
Kang
D011211:Electric Power Supplies; D012993:Solar Energy; D012995:Solubility; D013472:Sunlight; D013876:Thiophenes / Q000737:chemistry
D013876:Thiophenes
benzodithiophene; bulk-heterojunction solar cells; diketopyrrolopyrrole; donor-acceptor materials; small molecule solar cells