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

Abstract

The electron transport layer (ETL) exerts a dramatic influence on the power conversion efficiency (PCE) of the nonfullerene organic solar cells (NOSCs). Currently, the majority of the organic ETLs possess a relatively poor conductivity, which is not conducive to carrier transport and collection. Herein, we design and develop a novel hyperbranched conjugated polyelectrolyte (CPE) based on n-type perylene diimide (PDI) as the center core and quaternary ammonium salt as the side polar groups. The lone pair electrons of the nitrogen atoms can transfer to the electron deficient PDI core and endow the molecule with an efficient n-type self-doping effect. Moreover, the hyperbranched structure makes the molecule functionalized with more side polar groups, favoring forming more dipoles and stronger dipole moments. Therefore, the CPE PTPAPDINO possesses a high conductivity and can notably decrease the work function (WF) of the electrode, contributing to the carrier transport and collection of the device. The NOSC with PTPAPDINO as ETL delivers an excellent PCE of 15.62%, which is even superior to the device using the classical PDINO ETL. Moreover, the PCE can retain 82.6% of the optimal device when the thickness has been increased to 28 nm. These results manifest that it is a feasible strategy to design an n-type self-doping hyperbranched CPE as efficient ETL, and PTPAPDINO is a promising alternative ETL for high performance NOSCs.

Perylene‐diimide‐based cathode interlayer materials for high performance organic solar cells

“…Based on the classical CIM PDINO , a hyperbranched conjugated polyelectrolyte, PTPAPDINO (Figure 7), was synthesized by Chen et al . in 2021 73 . This result revealed that PTAPAPDINO had high conductivity, benefitting from a significant n ‐type self‐doping effect.…”

“…Based on the classical CIM PDINO, a hyperbranched conjugated polyelectrolyte, PTPAPDINO (Figure 7), was synthesized by Chen et al in 2021. 73 This result revealed that PTAPAPDINO had high conductivity, benefitting from a significant n-type self-doping effect. The research also indicates that PTAPAPDINO has a strong WF modifying ability due to more dipoles and stronger dipole moments constructed by the 3D structure.…”

Hole/Electron Transporting Materials for Nonfullerene Organic Solar Cells

“…Chen et al developed a hyperbranched conjugated polyelectrolyte, named PTPAPDINO, which possessed a high conductivity and could notably decrease the WF of the electrode, contributing to high carrier transport and collection of the device. [56] The n-type self-doping effect of PTPAPDINO also made the devices thickness-insensitivity. The chemical structures of the ETLs based on NDI and PDI derivatives are shown in Figure 7, and the corresponding photovoltaic properties are summarized in Table 5.…”

“…Chen et al. developed a hyperbranched conjugated polyelectrolyte, named PTPAPDINO, which possessed a high conductivity and could notably decrease the WF of the electrode, contributing to high carrier transport and collection of the device [56] . The n ‐type self‐doping effect of PTPAPDINO also made the devices thickness‐insensitivity.…”

Improving charge transport and reducing non-radiative energy loss via a nonacyclic carbazole-based third component for over 18% efficiency polymer solar cells

“…[1][2][3] Such achievements can be attributed to the rapid development of non-fullerene acceptors (NFAs), novel interfacial materials, and rened morphology optimization of active layers. [4][5][6][7][8][9][10] The ternary strategy of introducing a third component to extend the absorption of the solar spectrum is an effective and simple approach to realize a better device performance. [11][12][13][14] The third component could be a donor or an acceptor, and it should have good miscibility with the host binary blend.…”