A research group led by Prof. GE Ziyi at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS), has developed three isomeric bisphosphonate-anchored self-assembled molecules (SAMs), achieving high-efficiency and stable inverted perovskite solar cells (PSCs). 

This work was published in Advanced Materials.

PSCs have attracted extensive attention as a promising green energy technology, owing to their low fabrication cost, extraordinary power conversion efficiencies (PCEs).

The wettability, adsorbability and compactness of SAMs, which are employed as hole-transporting layers (HTLs) for PSCs, exert critical influence on the efficiency and stability of the devices. Thus researchers at NIMTE proposed a molecular strategy to synthesize three bisphosphonate-anchored indolocarbazole (IDCz)-derived SAMs, namely IDCz-1, IDCz-2, and IDCz-3. The three SAMs with different positions of the two nitrogen atoms in the IDCz unit were employed on conductive oxide substrates for inverted PSCs respectively.

Compared with IDCz-1 and IDCz-2, IDCz-3 exhibited larger dipole moment, higher energy level and bigger water contact angles, contributing to the hole extraction and electron blocking.

Consequently, the inverted PSC using IDCz-3 as HTL achieved a record high PCE of 25.15%, which is the highest value reported to date for multipodal SAMs-based PSCs.

When stored in a nitrogen environment at room temperature for 1,800 h, the IDCz-3-based device can almost maintain its initial efficiency, indicating its excellent long-term stability.

This work was supported by the National Science Fund for Distinguished Young Scholars (No.21925506), the National Natural Science Foundation of China (No.U21A20331), etc.

Fig. The high-performance inverted perovskite solar cells with bisphosphonate-anchored SAMs (Image by NIMTE)

Contact
YANG Daobin
Ningbo Institute of Materials Technology and Engineering
E-mail: yangdaobin@nimte.ac.cn