Synthesis And Photovoltaic Properties Of Small Molecule Receptor Materials Based On Noncovalent Organic Boron Fused Ring

Organic solar cell have many advantages,such as small limitation of raw materials,simple process and so on.Compared to traditional fullerene receptor materials,the A-D-A type fused ring receptor small molecule substances in non fullerene composite materials are easier to modify,and the spectral wavelength is also easier to adjust.Therefore,their photoelectric conversion efficiency can reach over18%,which has broad commercial prospects.However,the synthesis process of most fused ring receptors is complex and the reaction yield is not ideal,so the preparation cost is high,which will greatly limit the future application of organic solar cell.In practical applications,the energy conversion efficiency and stability of organic solar cell need to be further improved.To solve this problem,the use of fused ring backbone or fused ring building blocks in molecular design can obtain rigid and coplanar structures through non covalent bond,which is conducive to the construction of fused ring electron acceptor structures.Based on the above research background,this topic proposed the design,synthesis and photovoltaic performance research of A-π-A′-π-A type organic boron fused ring small molecule electron acceptor materials.（1）In Chapter 3,we designed and synthesized two new non fused ring receptors MBN-Th and MBN-Tz by introducing thiophene and thiazole asπbridges between BNBP and IC groups.Thiazole has electron deficient properties and is a widely used heterocyclic unit that accepts electrons.Negatively charged nitrogen atoms can lower the LUMO energy level of thiazole unit molecules.The nitrogen atom of the thiazole unit and the hydrogen atom on the BNBP unit can form a non covalent bond conformation lock to enhance the rigidity and flatness of the molecular skeleton,thereby reducing the recombination energy and improving the charge transfer mobility.（2）In Chapter 4,we designed and synthesized a new A-π-A′-π-A type fused ring receptor for MBN-3Th by introducing tri thiophene as aπbridge between BNBP and IC groups.The introduction of electron rich tribithiophene as aπbridge can effectively improve the intramolecular charge transfer and electronic structure,thus effectively increasing the band gap of A-π-A′-π-A type receptor,and red shifting the absorption spectrum of the material,thus improving the optical properties of the receptor.The introduction of electron rich tri bithiophene as aπbridge can improve the flatness of the molecular skeleton,and successfully reduce the energy level of the receptor body material by expanding the conjugated fused ring,thus improving the V_OC of the device.MBN-3Th can be used as the electron acceptor in organic solar cell.