Design And Synthesis Of Conjugated Amide Photomolecules And Study On Photovoltaic Solar Cell Devices

Acyl-imine n-type organic semiconductors have excellent electrical properties and chemical stability,and are widely applied in the fields of new solar cells,light-emitting diodes,and field-effect transistors.In the field of solar cells,molecules containing acyl-imine groups generally exhibit the following advantages: lower LUMO energy level,higher electron mobility,excellent stability,and good modifiability.However,the performance of photovoltaic devices based on acyl-imine n-type organic semiconductors still needs improvement.For example,the efficiency of perovskite solar cells using acyl-imine n-type organic semiconductors as electron transport materials is significantly lower than that of devices based on fullerene derivatives of the same type,and the efficiency of organic solar cells using acylimine n-type organic semiconductors as receptor materials is lower than that of devices using condensed ring receptor materials.In this study,two new types of acyl-imine n-type organic semiconductors were synthesized,aiming to enhance the material properties and device performance by introducing new structures.Finally,their photovoltaic performance as electron transport and receptor materials in perovskite solar cells and organic solar cells was investigated.(1)Electron transport materials(ETMs)play an important role in achieving high conversion efficiency(PCE)and long-term stability of inverted perovskite solar cells(p-i-n PSCs).[6,6]-Phenyl-C61-butyric acid methyl ester(PC61BM)is a representative ETM,but its cost is high and stability needs to be improved.In this study,a new soluble pyrrolo[3,4-c]pyrrole-1,4-dione derivative was synthesized and introduced as an ETM into p-i-n PSCs.Due to the different positions of the alkyl chains,the pyrrolo[3,4-c]pyrrole-1,4-dione derivative has three isomers,including two trans-isomers(named BBIN-1 and BBIN-3)and one cis-isomer(named BBIN-2).Photophysical studies showed that the cis-isomer BBIN-2 has a smaller bandgap,higher LUMO energy level,and higher electron mobility.Therefore,p-i-n PSCs using BBIN-2 as the ETM showed the highest PCE,with a champion value of 19.36%,significantly higher than the control device based on PC61BM(18.78%).In addition,due to the strong hydrophobicity of the BBIN series,devices using BBIN as the ETM exhibited good storage stability in air and nitrogen environments.This work not only demonstrates the potential of pyrrolo[3,4-c]pyrrole-1,4-dione dyes as ETMs in PSCs but also reveals the importance of molecular structure in modifying device behavior.(2)A new type of condensed acceptor material with acylimine as the end electronwithdrawing group was synthesized,and its performance in binary and ternary organic solar cells was studied.Condensed acceptor materials are currently the most promising acceptor materials in the field of organic solar cells,and halogen atoms are usually introduced to regulate their electrical and optical properties on the electron-withdrawing group of the end cyanideindanone group.The acylimine group has high stability and conjugation,and is expected to further improve the performance of condensed acceptor molecules such as Y6 and increase their application value in optoelectronic devices.In this paper,a condensed acceptor material BTPPIO-C4 with acylimine and indanone as the end electron-withdrawing group was synthesized,and its performance in organic solar cells was studied.The results showed that the PM6:Y6:BTP-PIO-C4 ternary BHJ device exhibited excellent photovoltaic performance(PCE= 16.53%),with a significant improvement in open-circuit voltage and short-circuit current,far surpassing the binary device.Further studies showed that the introduction of BTP-PIO-C4 not only improved the electron and hole mobility of the BHJ device,but also effectively improved the morphology of the blend film,promoted the separation and transfer of charges,and suppressed the recombination of carriers.This work successfully verified the possibility of modifying the Y6 end group with acylimine groups and obtained a new type of organic semiconductor material Y6-PIO-C4 with excellent electrical properties and good stability.This method is simple and efficient,and can provide new ideas and methods for the research and application of organic semiconductor acceptor materials.