Synthesis And Properties Of Highly Efficient Acceptor Organic Photovoltaic Materials

Organic solar cells,a new photovoltaic technology,has become the focus of academia and industry at home and abroad because of its low cost,light quality,simple preparation process and large area of flexible devices and so on.Especially for photovoltaic devices based on polymer donors and small molecule acceptor materials,the power conversion efficiency has exceeded 19%,which is benefited from the emergence of new photovoltaic materials and continuous progress of photovoltaic devices preparation technology.The efficiency of photovoltaic devices is closely related to the donor and acceptor materials used,this paper focuses on the organic photovoltaic acceptor materials,modifies the end group,and prepares a series of acceptor materials,and separately prepare binary and ternary devices to explore the properties of acceptor materials.The specific study contents and results were as follows:1.At present,the terminal modification of small molecule acceptor material mainly starts from the two aspects,broadening the conjugation length of the end group and halogenation.Expanding the conjugation length of terminal group can increase the electron delocalization,enhance intermolecular charge transfer,optimize the morphology of phase separation and blend film,and improve carrier mobility.Halogenation can be used to adjust the energy level,band gap,absorption,and reduce charge recombination of materials.In this thesis,the materials were modified by fluorination and extended end group strategy,and the small molecule acceptor materials TN and TNF,IN and INF,AN and ANF were prepared.It is found that when the F atom was introduced at the end group of acceptor material,the electron withdrawing ability of the material increases,and the absorption spectrum has a red shifted,which is beneficial to the promotion of the power conversion efficiency of the device.2.Using the prepared small molecule acceptor material AN,the binary photovoltaic device was fabricated,and the device structure is glass/ITO/PEDOT:PSS/PM6:AN/PFN-Br/Ag.And the binary photovoltaic device achieved a10.63% power conversion efficiency with annealing temperature of 100 ℃ and additive of 0.5%CN.After adding AN as the third component to the PM6:Y6、PM6:BTP-e C9 and PM6:L8-BO,respectively,we found that the power conversion efficiency of the ternary photovoltaic device based on PM6:BTP-e C9:AN(1:1.2:0.1),with structure of Glass/ITO/PEDOT:PSS/PM6:BTP-e C9:AN/PFN-Br/Ag,was improved to 17.61%,indicating that the introduction of AN as the third component into the binary system is successful,and it can effectively improve the efficiency of the photovoltaic device.