Abstract
Two novel D-π-A-π-D type non-fullerene acceptors (FPTC and CPTC) composed of fluorene or carbazole as acceptor unit, benzene as intermediates and 2-(6-oxo-5,6-dihydro-4H-cyclopenta[c] thiophen-4-ylidene) malononitrile (TC) as terminal groups are synthesized through only two procedures. Also, their electrochemical behavior, photophysical properties and photovoltaic performance are systematically characterized and thoroughly studied. In consequence, the FPTC has better performance than C PTC, and the PCE of this device based on FPTC: PTB7-Th is nearly 1% higher than that of CPTC: PTB7-Th device, reaching up to 1.09% with a V OC of 0.71 V, a J SC of 3.42 mA cm − 2 . The higher PCE of the device based on FPTC is attributed to the fact that this molecular has a wider absorption spectrum and a higher molar extinction coefficient nearly four times than that of CPTC, a higher initial oxidation potential, and a lower onset reduction potential. Also, the higher electron mobility rate and hole mobility rate contribute to the device based on FPTC better performances. Compared with carbazole, the fluorene as the acceptor unit provides potential possibilities for the construction of high-performance organic solar cells.
Investigation on Film Quality and Photophysical Properties of Narrow Bandgap Molecular Semiconductor Thin Film and Its Solar Cell Application