Synthesis And Photovoltaic Performance Study Of Heteroatom-fused Perylene Diimides(PDIs) Acceptors

The sun provides the largest source of energy known to man,and people use a variety of ways to convert light energy to use solar energy.At present,solar energy conversion is still committed to the research and development of new materials and new equipment.The most potential related field is solar photovoltaic materials.Improving efficiency,reducing costs,stability and commercialization issues are the current research priorities in the field of solar photovoltaic materials.Continued progress is strategic for mitigating climate change impacts and energy security.Perylene Diimides?PDIs?are cheap and readily available organic dyes with strong absorption in the visible region,good thermal and light stability,and have been widely used in near-infrared dyes and organic field-effect transistors in recent years.The perylene diimide has a higher electron affinity?lower LUMO energy level?and has a high electron mobility in the stacking direction due to its?-?stacking between the conjugated large?bonds.However,large planar structures tend to form excessive crystalline domains,limiting their use in organic solar cells?OSCs?.In order to suppress the aggregation tendency of PDIs,hetero atoms such as O,S,and Se may be incorporated into the bay position of the PDIs unit,thereby changing the photoelectric properties of the perylene diimides.The nature of the excited states in organic molecules determines their numerous optical properties,and rational design of organic materials to achieve excited states with custom optical properties remains a major challenge.The two-photon?TPA?process is a nonlinear optical?NLO?phenomenon that can be evaluated by accessing the TPA.One of the molecules can absorb two photons with the same or different frequencies to excite from one state to a higher energy state.Organic molecules with high two-photon absorption characteristics have attracted the attention of researchers due to their potential applications in three-dimensional?3D?fluorescence imaging,laser upconversion and 3D optical data storage.Organic?-conjugated compounds have been widely used as NLO materials to enhance the TPA absorption cross section due to their clear structural diversity,flexibility and functionality,fast response and variable band gap.Based on the above reasons,we designed and synthesized a series of organic materials for organic solar cells and nonlinear optics.The main work is as follows:???A new propeller-shaped PDIs acceptor material was designed,with tetraphenyl styrene?TPE?as the core and S/Se heterocyclic fused PDIs at the bay,and suitable donor materials were selected to prepare battery devices.Achieve higher battery efficiency.The TPE-PDI₄-Se device with PBDB-T1 as donor has a photoelectric conversion efficiency?PCE?of 7.63%,a V_OC of 1.08 V,a J_SC of 10.28mA cm^-2,and a fill factor of 68.8%,compared to TPE-PDI-S device,PCE increased by 11.4%?6.85%?.???In order to study the effect of the same oxygen elements O,S,Se on the photoelectric properties of solar cells after modification of the PDIs,we designed a PDI with spirulina as the core and fused with different oxygen atoms.The peripheral group obtained the target receptor material?SF-PDI-O,SF-PDI-S,SF-PDI-Se?.Cell materials were prepared by selecting the donor materials with spectra and energy levels matching,and the effects of PDIs doped with different oxygen atoms on the photoelectric properties were investigated.???Three new types of azaheterocarbons with tetraazaphthalene units as the core,namely,SDNU-1,SDNU-2 and SDNU-3,were designed and synthesized.Four triisopropylsilyl-acetylene?TIPS?groups are attached to the backbone,which ensures that the prepared azaarrene is readily soluble in common organic solvents.The solid-state luminescence quantum efficiency?PLQEs?of the compound SDNU-2 is as high as 75.3%,which is the highest efficiency of the current aza-aromatics.This result provides valuable guidance for designing new azole-based aromatic materials.