| dc.description.abstract | A series of new organic optoelectronic materials based on benzoselenadiazole (BT) were developed and characterized for the applications in perovskite solar cells (PSCs).
In this work, four newly developed HTMs (DTPBT-2D (1), DTBTN-2D (2), DTPBT-SBT (3), DTBTN-SBT (4)) were synthesized by conjugating DTPBT and DTBTN core to triphenylamine (TPA) or polymerizing with dithioalkylbithiophene (SBT). So far, the state-of-the-art hole-transporting materials (HTMs) with benzothiadiazole unit have been widely used in high effiency PSCs. Benefit from the strong electron withdrawing ability which derived from nitro groups, DTBTN core can afford good intramolecular charge transfer phenomenon. Intermolecular - interaction is enhanced due to the fused ring structure of DTPBT core, and the good solubility is maintained by introducing branched alkyl chain to the planar core. For the development of polymeric HTMs, highly planar structures can be obtained due to the intramolecular S---S interactions between thioalkyl chain and sulfur atom on the adjacent thiophene. Furthermore, the presence of electron rich sulfur and nitro atoms exhibit a good interaction with undercoordinated Pb2 ions and passivate the trap states in the perovskite films. Based on the above advantages, these newly developed compounds are expected to perform well in PSCs.
Currently, DTPBT-2D (1) and DTBTN-2D (2) have been applied in tin-based perovskite solar cell, and the devices exihibited power conversion efficiency of 6.2% and 5.6%, respectively.
The chemical structures of these newly developed materials were characterized by NMR spectroscopy and mass spectrometry. Further, the optical properties of these compounds were investigated by UV-Vis spectroscopy, electrochemical analyses were analyzed by DPV, and the thermal stabilities were determined by DSC and TGA. Optoelectronic devices made from these newly developed small molecules are under optimization. | en_US |