Ternary Blend Polymer Solar Cells

Organic solar cells?OSCs?have been widely regarded as a kind of promising green and renewable energy technology,because they can be solution-processed,light-weight,and easily fabricated on the flexible substrates.The prospective advance of OSCs into the PCE range of 15-20%is suggested lie on the innovative design of photoactive layer to a large extent.This thesis mainly do the research of the following three aspects:First,Inverted organic solar cells?OSCs?have been fabricated using the photoactive blend thin films based on regioregular poly?3-hexylthiophene??P3HT?,[6,6]-phenyl C₆₁-butyric acid methyl ester?PCBM?,and leuco crystal violet?LCV?.It was found that the LCV as an efficient n-dopant could significantly increase intrinsic electron concentration of PCBM zone.The electron mobility of P3HT:PCBM:LCV blend thin film was measured 0.75 times higher than that of P3HT:PCBM blend thin film,as a result of LCV-induced trap filling in the bandgap of PCBM.Compared to the inverted device using the conventional photoactive layer of P3HT:PCBM,the one using the photoactive layer of P3HT:PCBM:LCV showed an increase of 0.22 times in power conversion efficiency.Secondly,LiF,Alq3 and BCP were used as cathode buffer layer in the heterojunction organic photovoltaic based on ITO/P3HT:PCBM/cathode buffer layer/Al,and their effects on the performance of the devices were investigated.Results showed that the device performance was best when the cathode buffer is 5 nm BCP.When the structure of cathode buffer is BCP/Alq3/LiF,the devices performance depended on the thickness of BCP.With the increase of thickness of BCP,the performance of devices increase.Finally,The sandwiched-p-doped-layer hole injection structure of CBP:MoO₃ 10nm/NPB:MoO₃ 5 nm/CBP:MoO₃ 5 nm/Al showed increased device performance via enhancing hole current into the CBP,compared to the single-p-doped-layer hole injection structure of CBP:MoO₃ 20 nm/Al;it also improved device current and thereby performance than the double-p-doped-layer hole injection structure of CBP:MoO₃ 10 nm/NPB:MoO₃ 10 nm/Al,mostly attributed to that the hole injection from Al to CBP:MoO₃ was more efficient than that from Al to NPB:MoO₃.