The Research Of Ternary Blend Organic Solar Cells And Tandem Organic Solar Cells

Polymer solar cells with the features of light weight,environmental protection,low consumption have attracted much attention in new energy photovoltaic field.The power conversion efficiency?PCE?of polymer solar cells?PSCs?has reached 14%.The spectral absorption range of binary polymer solar cells is narrow,photon acquisition ability is bad,the power conversion efficiency of solar cells are largely affected by these limiting factors.Prepare ternary polymer solar cells and tandem polymer solar cells by blending two different band gap of donor materials and overlay batteries of different band gap materials to broaden the characteristic of spectral absorption,to complement the absorption spectral range of solar cell,to improve the utilization rate of solar energy spectrum.In this thesis,we study the effect of the device performance that use PBT-T-DPP and PTT-DTNT-DT as the complementary electron donor in poly?3-hexylthiophene??P3HT?and PCBM[6,6]-phenyl-C61-butyricacid methyl ester(PC₆₁BM)blend to construct the ternary PSCs.And study the device performance of the tandem solar cells with the P3HT:PC₆₁BM as active layers of bottom solar cells and PT-DTNT-DT:PCBM[6,6]-phenyl-C71-butyric acid methyl ester(PC₇₁BM),DPPT-TT:PC₇₁BM as active layers of top solar cells.Firstly,Study the influence of the devices by using PBT-T-DPP as the third complementary electron donor in P3 HT and PC₆₁BM blend to construct the ternary PSCs.The PCE of the optimized ternary blend PSCs reached 3.68%by adding 5wt%PBT-T-DPP,which is 16.46%higher than that of the PSCs of binary blends of P3HT:PC₆₁BM,with the highest open-circuit voltage(V_OC),short-circuit current density(J_SC)and a fill factor?FF?.Further increasing the PBT-T-DPP content yield a decreased solar cell performance with inferior J_SCC and FF compared with the P3HT:PC₆₁BM devices.under the short-circuit current condition,The P?E,T?of ternary solar cells with 5%PBT-T-DPP is 84.37%compared with the binary polymer battery increased by 3.8%.Next,we focus on the study of PTT-DTNT-DT as the electron-cascade donor materials in organic solar cells based on P3HT:PC₆₁BM blend.When the ratio is 20%of PTT-DTNT-DT,we obtained the highest PCE is 4.66%with the optimum device performance.Increasing the proportion of PTT-DTNT-DT,the performance of ternary device is decrease continuously.The J_ph/J_satat of ternary solar cells with 20%PTT-DTNT-DT is 94.60%and the P3HT:PC₆₁BM blend device is 90.82%at short-circuit current conditions.About the surface morphology of the device,we find that the film surface morphology with the 20%PTT-DTNT-DT is optimal.The tandem polymer solar cells structure is an efficient method to improve the power conversion efficiency,PT-DTNT-DT and DPPT-TT are low bandgap polymers.P3HT:PC₆₁-BM as the active layers of bottom cells and PT-DTNT-DT:PC₇₁BM,DPPT-TT:PC₇₁BM as active layers of top cells respectively.MoO₃/Ag/PFN as intermediate link layer of tandem device,which obtain the superimposed open-circuit voltage?1.30V?,the highest PCE of3.83%,but J_SCis restricted to the smallest battery current density,if the current density can be improved,the power conversion efficiency of tandem solar cells will be higher than before.The results demonstrate that PBT-T-DPP and PTT-DTNT-DT as complementary electron donor in P3HT:PC₆₁BM to fabricate ternary polymer device can broaden spectral absorption,which improving the performance of ternary polymer solar cells.Prepare the tandem solar cells with PT-DTNT-DT:PC₇₁BM,DPPT-TT:PC₇₁BM as the active layers of top cells to fabricate tandem solar cells,the absorption spectrum of batteries complementary,so it's also an excellent method to improve efficiency.