Amphiphilic Diblock Fullerene Derivatives as Cathode Interfacial Layers for Organic Solar Cells

作者：Liu, Jikang; Li, Junli; Liu, Xiangfu; Li, Fu; Tu, Guoli^*

来源：ACS Applied Materials & Interfaces, 2018, 10(3): 2649-2657.

DOI：10.1021/acsami.7b18331

• organic solar cells
• amphiphilic diblock
• solvent annealing
• self-assembly
• water contact angle
• interfacial compatibility
• interface morphology

A new amphiphilic diblock fullerene derivative [6,6]-phenyl-C-61-butyricacid-4(9,9,9',9'-tetrakis(3-brompropropyl)-9H,9'H-[2,2'-bifluoren]-7-yl)phenol-(N,N,N-trimethylpropan-1-aminium) bromide (C-60-4TPB) was synthesized and applied in organic solar cells. Solvent annealing by toluene could obviously induce the self-assembly of the C-60-4TPB layer, which can be tested by the measurements of the water contact angle. After the treatment with toluene, a vertical-like arrangement in the ultrathin layer of the C-60-4TPB molecule will be formed between electron-collecting zinc oxide (ZnO) layers and the active layer (blend system. of PTB7:PC71BM), leading to the improvement of the interfacial compatibility between the active layer and the ZnO layer. On the top surface of the C-60-4TPB layer, the C-60 molecules can be expected to induce the enrichment of PC71BM and block the hole, resulting in further increase in the open-circuit voltage (V-OC) and fill factor(FE). After spin-coating the C-60- 4TPB solutions onto the ZnO layer with a concentration of 0.5 mg/mL in dimethyl sulfoxide, obviously improved performances were obtained with a power conversion efficiency of 8.07% which can be attributed to the optimized interface morphology between hydrophilic ZnO and hydrophobic PTB7:PC71BM.

• 出版日期2018-1-24
• 单位华中科技大学