The Research Of Key Materials In Highly Efficient And Stable Perovskite Solar Cells

Organolead halide perovskite solar cells?PSCs?have drawn great attention due to their outstanding merits such as high power conversion efficiency?PCE?,simple preparation technology and low manufacture costs.In just a few years,the development is extremely rapid and the highest PCE has reached to 22.1%.It is the research focus to select and optimize their key component materials to achieve satisfied performance and stability.In this thesis,both the device performance and application potential were increased by optimizing the light-absorbing perovskite materials and hole-transporting materials.?1?Twonovelasymmetriccoumarinmodifiedasymmetric carboxyphthalocyanines,ZnPc-Cou and Pc-Cou,were synthesized from 7-?3,4-dicyanophenoxy?-4-methylcoumarin and 4,5-dicyano dimethyl phthalate by the template method.The synthesis of intermediates were optimized.We applied these two metallophthalocyanines on both interface modification and co-sensitization in a mesoporous PSC.The PCE of ZnPc-Cou and Pc-Cou-based solar cell give an increase of 3.41%and 3.00%to 13.96%and 13.55%compared to CH₃NH₃PbI₃-sensitized devices,respectively.The introduction of novel asymmetry metallophthalocyanines can not only favor crystal growth of CH₃NH₃PbI₃ leading to a better carrier collection and retardation of charge recombination but also improve the light harvesting ability of perovskite resulting in a faster electron injection.?2?Three kinds of small molecule hole transport materials,Z1011,Z1012 and Z1013,were designed and synthesized by Wittig-Horner reaction and Heck coupling reaction.The yields were 95.0%,91.0%and 57.1%,respectively.The HOMO levels of the compounds obtained by cyclic voltammetry were-5.21 eV,-5.39 eV and-5.14eV,respectively.In the presence of Z1011,Z1012 and Z1013 as HTM without dopants,PCE of 16.3%,13.0%and 15.3%were obtained,which are comparable to that of devices based on the well-known doped spiro-OMeTAD?16.5%?.Importantly,the PCE for devices based-on Z1011 dropped 10%after 500 h light soaking and dropped 24%after 200 h in ambient air without encapsulation at 80?,respectively,which is better than that of devices based on spiro-OMeTAD.?3?Two kinds of thiophene derivative hole transporting materials with methoxy thiophene as the core,Z25 and Z26,were synthesized by Suzuki cross-coupling reaction or Horner-Wadsworth-Emmons reaction.The hole mobility of the two compounds determined by time-of-flight measurements were 7.66×10^-5 cm² V^-1 s^-1and 1.34×10^-4 cm² V^-1 s^-1,respectively,at an electric field intensity of 1.5×10⁵ V cm^-1.The calculated initial cost of the two materials were 31.91$/g and 35.57$/g,respectively.The Z26 and Z25-based PSCs exhibited a remarkable PCE of 20.1%and16.9%,respectively,which were comparable to 20.6%obtained by spiro-OMeTAD-based device.Importantly,the PCE maintained 85.5%and 66.8%of the initial value after 800h in the Z26 and Z25-based perovskite solar cell when aged under ambient air of 30%relative humidity in the dark and there is 14%and 42%efficiency drop after 300 h under continuous full sun illumination and maximum power point tracking for Z26 and Z25-based PSCs,respectively.?4?The pure bis-PCBM isomer?-bis-PCBM was employed in antisolvent chlorobenzene as a templating agent to regulate the growth process of the perovskite crystals.?-bis-PCBM fills the vacancies and grain boundaries of the perovskite film,enhancing the crystallization of perovskites and addressing the issue of slow electron extraction.In addition,?-bis-PCBM passivates voids or pinholes generated in the hole-transporting layer.As a result,we obtain a PCE of 20.8%,which is significantly higher than that of control perovskite solar cells?18.8%?.The PCE of devcies dropped by less than 10%in ambient air?40%RH?after 44 days at 65?and by 4%after 600 h under continuous full sun illuminationand maximum power point tracking respectively.