Synthesis Of Novel Hole Transport Materials And Their Application In Perovskite Solar Cells

Organic-inorganic halide perovskite solar cells(PSCs)have witnessed rapid development of photovoltaic efficiency in the past decade,attracting a large number of researchers to constantly explore its photoelectric conversion efficiency from the initial 3.9% in 2009 to the current 25.2%,surpassing that of multicrystalline silicon solar cells.Compared with other solar cells,PSCs have a simple fabrication procedure,a low preparation cost,a good thermal stability,a high light absorption coefficient,a long charge diffusion distance and so on.However,for the commercialization of PSCs,there are still a series of shortcomings that need to be addressed,such as the toxicity of raw materials,the poor stability of materials,and the short life of the whole devices.At present,the PSC is mainly composed of cathode and anode electrodes,hole transport layer,perovskite layer and electron transport layer.Among them,the hole transport play important roles in the PSC.In this thesis,hole transport materials(HTMs),as well as the design,synthesis and application of new HTMs in PSCs are studied.Starting from the working principle of PSCs,this paper introduces the working processes of PSCs in detail,then explores the HTMs in PSCs.On the basis of the working principle of PSCs,we have obtained the requirements required for the hole transport material,designs the molecular structure and synthetic route of new HTMs,conducts their syntheses,and applies them in the device with a comparison with other HTMs.The research content of this paper is polymer HTMs,we additionally add a thiophene unit into the main chain of the polymer DTB that was previously designed by our group to construct a new polymer TTB,and use thiophene as electron donor group to improve the overall performance of the material and device performance.At the same time,the introduction of thiophene can increase the interaction between HTM and perovskite,and thus improve the hole extraction ability.Moreover,this new hole-transporting material achieves a higher hole mobility,ultimately leading to a photoelectric conversion efficiency of 18.2% for its perovskite solar cell,exceeding the efficiency of DTB and P3 HT based devices.With this high efficiency as well as a simple fabrication process and low cost,TTB is expected to be able to replace other hole transport materials.