Dopant Free Donor-Acceptor Type Polymer Hole Transport Materials for Efficient and Stable Perovskite Solar Cells

OpenAlex İngilizce

A new donor–acceptor type polymers containing benzothiadiazole (HB1) and benzoselenidiazole (HB2) as acceptor units were prepared or use as hole transport layers in perovskite solar cells (PSCs). It was observed that the electrochemical HOMO–LUMO band gap narrowed from 2.74 to 1.88 depending on the variation in the acceptor unit. In addition, the charge-transfer band at 580 nm undergoes a 30 nm red-shift and broadens to the near-infrared region. HB1 and HB2 were introduced as dopant-free HTMs to replace the commonly used 2,2′,7,7′-tetrakis[ N, N -di(4-methoxyphenyl)amino]-9–9′-spirobifluorene (spiro-OMeTAD) in planar heterojunction n-i-p type of PSCs. Compared with HB2, HB1 exhibited better film morphology and mobility, resulting in improved charge-carrier extraction and transport. Dopant-free HB1 devices fabricated using the Cs0.05FA0.79MA0.16-Pb (IxBr1-x)3 triple cation perovskite displayed a champion power conversion efficiency of 11.69% under one sun illumination (100 mW cm -2 ) which is higher than the efficiency of HB2-based devices. The inflated performance was attributed to the reduced charge recombination and improved conductivity. In addition, these new HTMs exhibited higher hydrophobicity and thermal stability than their doped spiro-OMeTAD counterpart, making it possible to achieve good stability.