| dc.description.abstract | A series of new organic optoelectronic materials were synthesized and characterized for organic thin film transistors (OTFTs), organic photovoltaic cells (OPVs), and hole transporting layers (HTLs).
For the OTFTs, CDTS-based quinoidals with three different alkyl chains, CDTSQ-8 (1), CDTSQ-10 (2) and CDTSQ-12 (3) were synthesized. At the same time, the electron withdrawing group INCl was connected to the core (CDTS) to give INClCDTS-10 (4). Single-crystal X-ray diffraction of CDTSQ-10 (2) and CDTSQ-12 (3) have obtained and reveal intermolecular interaction between S and N, which promote a tight molecular stacking. Currently, via solution shearing, CDTSQ-10 (2) exhibits the best n-channel transport with the highest mobility up to 0.1 cm2V-1s-1. Optoelectronic devices based on these new developed small molecules are under examination and optimization.
For the organic photovoltaics, 2-bromo-3-thioalkylthiophene were formylated to give isomeric 4- and 5-CHO-TSRBr in two different reaction conditions. Further, both new units were coupled with CDT and CDTS to give four new cores, TCDT and TCDTS. Lastly, the above four cores were end-capped with two electron withdrawing groups, IN and INCl, to give IN-TCDT (5), INCl-TCDT (6), 4-IN-TCDT (7) and 4-INCl-TCDT (8) for the TCDT series and IN-TCDTS (9), INCl-TCDTS (10), 4-IN-TCDTS (11) and 4-INCl-TCDTS (12) for the TCDTS series.
Finally, one new CDTS-based hole transporting molecule was developed, where the CDTS core was end-capped with triphenylamino (TPA) unit. For comparison, CDT-based hole transporting molecule CDT-2D (13) was synthesized. It is found that the energy gap of CDTS-2D (14) is much smaller than CDT-2D (13). Currently, CDTS-2D (14) as additive exhibits power conversion efficiency of 14.04% in Pb-based PSC.
The optical and electrochemical properties (HOMO and LUMO) of these new materials were characterized by UV-vis and DPV. Thermal properties were investigated by DSC and TGA. Optoelectronic devices used these new developed small molecules are under optimization. | en_US |