Performance Improvement Of Rubrene/C₇₀ Based Organic Solar Cells With Buffer Layer

Organic solar cells(OSCs) have become a research hotspot because of their promising properties such as simple process, more material,high mechanical flexibility,low cost and large area. Improving the power conversion efficiency of OSCs is the current research focus and improving the electrode contact of OSCs is an effective means to improve the efficiency of OSCs. In this thesis, Rubrene/C70 based OSCs were fabricated. Performance improvement of the OSCs with anode buffer layer and cathode buffer layer was investaged:1. The performance improvement of Rubrene/C70 based OSCs with WO3 as buffer layer was studied in this thesis. The OSCs with the structure of IT0/WO3/Rubrene/C70/BCP/Al were fabricated. WO3 was used as anode buffer layer by inserting between ITO and Rubrene. The performance and mechanism of the OSCs was studied by inserting WO3 with different thicknesses as buffer layer.The experiments show that the characteristic parameters of the OSCs including the short-circuit current(Jsc), open-circuit voltage(Voc), filling factor(FF), series resistance(Rs)and power conversion efficiency(PCE) have a regular change with different WO3 thicknesses as buffer layers. The PCE of the device is as high as 1.03 % with 80 nm WO3 while the Jsc, Voc, FF and Rs of the OSCs is 2.81 m A·cm-2, 0.83 V, 43.85% and 45.3Ω·cm2, respectively.Compared with the device without buffer layer, the Jsc, Voc, FF and PCE of the OSCs are enhanced by 31%, 137%, 17% and 268%, respectively. Rs is reduced by 33%.2. The OSCs with the structure of ITO/ZnO/C70/Rubrene/Mo O3/Al were fabricated to study the performance improvement of Rubrene/C70 based OSCs with Zn O. Zn O was used as cathode buffer layer by inserting between ITO and C70. Simultaneously,the mechanism of the OSCs was studied by inserting Zn O with different thicknesses as cathode buffer layer. As can be seen from the experimental results,the characteristic parameters of the OSCs including the Jsc, Voc, FF,PCE and Rs show a regular change with different Zn O thicknesses. The PCE of the device are as high as 1.13 % with 53 nm Zn O while the Jsc, Voc, FF and Rs of the OSCs is 2.82 m A·cm-2,0.84 V, 45.86% and 66.2Ω·cm2, respectively. Compared with the device without Zn O, the Jsc,Voc, FF and PCE of the best OSCs are enhanced by 49%, 29%, 17% and 117%, respectively. Rs is reduced by 56%.