Intermolecular n-Doping Nonconjugated Polymer Cathode Interfacial Materials for Organic Solar Cells

Abstract

Three alcohol-soluble nonconjugated polymers poly [p-(N,N-dimethylamino)­styrene] (PSN), poly­[p-(N,N-dimethylamino)­styrene] oxide (PSO), and poly­[p-(N,N-dimethylamino)­styrene] mesylate (PSM) were devised and synthesized for the application as cathode interlayers in the organic solar cells (OSCs) based on PBDB-T:IT-M. All of the polymers contain a highly polarized amino or ammonium group at the side chains, which can improve electron collection ability of the cathode interfacial layer of the OSCs. Both the amino and ammonium group with a negative ion of oxygen allow PSN and PSO to possess intermolecular n-doping effect with the IT-M acceptor at the interface. The understanding of the relationship between the n-doping effect and the cathode interlayer structures may offer additional insights to further develop novel cathode interfacial materials for OSCs.

Recent progress in cathode interlayer materials for non‐fullerene organic solar cells

“…While PFN‐Br eliminates the excessive doping effect and makes the electrons extraction easier (Figure 9E–H). Lv et al 190 explored the effect of the pendant polar group of CILs and the interface doping phenomena. They used nonconjugated polymers PSN, PSO, PSM having different pendant polar groups (amine, ammonium oxide, and ammonium mesylate) as CILs using PBDB‐T:IT‐M photoactive layer.…”

N-Type Self-Doped Hyperbranched Conjugated Polyelectrolyte as Electron Transport Layer for Efficient Nonfullerene Organic Solar Cells

“…N-type doping, as an approach to enhance the charge transmission of nonfullerene organic solar cells (NOSCs), mainly adopts adding external dopants, which will affect the stability of the devices. Consequently, the relatively stable n-type self-doping effect possesses great superiorities. − The interfacial control ability and the conductivity of the self-doped ETL materials will be improved due to the formation of the additional large dipoles generated by the self-doped effect, which will make them insensitive to the thickness. , Chen et al first designed an efficient n-type CPE PDPPNBr as ETL with a characteristic of thickness insensitivity. The PDPPNBr possessed high conductivity and superior electron mobility due to its n-type DPP conjugated backbone.…”

“…29−31 The interfacial control ability and the conductivity of the self-doped ETL materials will be improved due to the formation of the additional large dipoles generated by the self-doped effect, which will make them insensitive to the thickness. 32,33 Chen 34 et al first designed an efficient ntype CPE PDPPNBr as ETL with a characteristic of thickness insensitivity. The PDPPNBr possessed high conductivity and superior electron mobility due to its n-type DPP conjugated backbone.…”

Water–Alcohol-Soluble Hyperbranched Polyelectrolytes and Their Application in Polymer Solar Cells and Photocatalysis

“…Compared to most of the traditional organic semiconductors, which are soluble in nonpolar/low-polar solvents, WSCPs possess unique solubility in polar solvents, such as water, methanol, and so on, facilitating orthogonal processability to fabricate multilayer optoelectronic devices and prevent the solvent erosion problem. ,− The π-conjugated backbone of WSCPs provides a band structure, absorption and emission spectra, and good electron transporting characteristics, rendering wide application in optoelectronic devices. For example, WSCPs have been excellently used as interlayer materials in PSCs by improving the electron/hole collection in the electrode. ,− The multiple functions of WSCPs, including work function alternation, hole blocking, interface doping, and morphology optimization have contributed to the overall improvement in the photovoltaic performance of PSCs. − …”