A series of asymmetric squaraine small molecules containing indoline derivative structures and their applications

Abstract

The invention provides a series of novel asymmetric squaraine small molecules and their application. By introducing different electric-rich aromatic units at both ends of the squaraine four-membered ring as donor units, a series of low-bandgap asymmetric squaraine small-molecule photovoltaic materials were designed and synthesized, which have strong photoelectric properties in the visible and near-infrared regions. The absorption spectrum covers 400‑900 nm; its HOMO and LUMO match well with the energy level of the acceptor material PCBM, and a high open circuit voltage is obtained, and these compounds have good solubility and film-forming properties, making them suitable for Application to low-cost solution-processed bulk heterojunction organic solar cell devices. The performance of organic solar cells using asymmetric squarylium small molecules as donor materials can reach: under white light 1.5 G (100 mw / cm2) irradiation, open circuit voltage (Voc) = 0.72‑1.05V, short circuit current (Jsc) = 8.80 ‑12.67 mA / cm2, fill factor (FF)=0.38‑0.55, photoelectric conversion efficiency (PCE)=2.41‑6.10%.

Description

1. Technical field [0001] The invention relates to a series of asymmetric squaraine small molecules containing indoline derivative structures and a preparation method, as well as the application of the squaraine small molecules in the field of organic solar cells. 2. Background technology [0002] At present, the energy crisis and environmental problems are becoming more and more severe, and solar energy, as an inexhaustible clean energy, has attracted everyone's attention. Solar cells are one of the important means of utilizing solar energy, and are mainly divided into inorganic solar cells and organic solar cells (OPV). Compared with inorganic solar cells, organic solar cells have significant advantages such as light weight, low cost, and good flexibility. In recent decades, great progress has been made in the design and synthesis of new organic photovoltaic materials and the design and optimization of device structures. Compared with polymer photovoltaic materials, smal...

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Problems solved by technology

However, because the synthesis steps of asymmetric squaraine small molecules are slightly more, and the performance is relatively low, it is not widely studied in OPV.

Currently, there are only 6 literatures on the application of small asymmetric squaraine molecules in the field of organic solar cells (Angew.Chem.Int.Ed.2009, 48, 8776-8779; Sol.Energy Mater.Sol.Cells 2012, 98, 224-232; ACS Nano 2012, 6, 972-978; J.Mater.Chem.2012, 22, 6704-6710; Phys.Chem.Chem.Phys.2012, 14, 8382-8334; Chem.Commun. 2013,49,10465-10467.), the material performance reported in ACS Nano is the best, but the optical energy gap is about 2.0eV, which is relatively high and does not match well with the solar spectrum

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