A Hyperbranched Conjugated Polymer as the Cathode Interlayer for High‐Performance Polymer Solar Cells

Abstract

An alcohol-soluble hyperbranched conjugated polymer HBPFN with a dimethylamino moiety is synthesized and used as a cathode interlayer. A PCE of 7.7% is obtained for PBDTTT-C-T/PC71 BM based solar cells. No obvious interfacial dipole is found at the interface between the active layer and HBPFN however, an interfacial dipole with the cathode could be one of the reasons for the enhanced performance.

An alcohol-soluble perylene diimide derivative as cathode interfacial layer for PDI-based nonfullerene organic solar cells

“…Alternatively, a variety of water/alcohol-soluble organic electron collection materials have been successfully used as the cathode interfacial layer in OPVs, such as poly(ethylene oxide) (PEO) [16], conjugated polyfluorene derivatives with side chains containing amino end groups (PFN) [17,18] or metal ion-intercalated crown ether (PFCn6:K + ) [19], and insulating polymers with amine group such as polyethylenimine (PEIE) [20,21]. Such kind of organicbased interfacial layers that can be created via solution-processed method may be desirable for the realization of low-cost and large-area OPV devices.…”

Insights into the working mechanism of cathode interlayers in polymer solar cells via [(C8H17)4N]4[SiW12O40]

“…[1][2][3][4][5] One of the efficient strategies to achieve such a high efficiency was the application of an alcohol/ water soluble cathode interlayer (CIL). Alcohol/water-soluble CILs reported so far mainly consist of conjugated polymers [6][7][8][9][10][11][12][13][14] and small molecules. [15][16][17][18][19][20][21][22][23][24][25][26] However it is difficult to massively utilize the materials for low cost and large-area roll to roll production of PSCs because the CIL molecules containing complicated p conjugated units require difficult and complicated synthetic procedures resulting in high cost in terms of production and environment.…”

The effect of interfacial diffusion on device performance of polymer solar cells: a quantitative view by active-layer doping

“…The power conversion efficiency of iPSCs, which has rapidly increased, has already reached efficiencies of up to 9.2% with good ambient stability [5]. One key advance in the achievement of such efficiency values is the use of an alcohol-soluble conjugated polymer (PFN; Figure 1(a)) as the cathode interlayer [17,18]. Using PFN as the cathode interlayer can significantly reduce the contact barrier between electrode and active layer and facilitate the charge transport [19].…”