| Institution: | 1. School of Environment and Energy, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510000 China
Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong, China;2. School of Environment and Energy, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510000 China;3. Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong, China;4. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 China;5. Center of Excellence in Nanoscience (CAS), Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS), National Center for Nanoscience and Technology, Beijing, 100190 China;6. Energy Centre, Council for Scientific and Industrial Research (CSIR), P O Box 395, Pretoria, 0001 South Africa |
| Abstract: | All-inorganic n-i-p perovskite solar cells (PSCs) using doped Spiro-OMeTAD as hole transport material (HTM) suffer from photothermal stability due to ionic diffusion and radical-induced degradation by the dopants. In this article, dopant-free starlike molecule (N2, N2-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-N5,N5-bis(4-methoxyphenyl)pyridine-2,5-diamine (BD)) is synthesized to engineer the stacking properties and delivered higher hole mobility than doped Spiro-OMeTAD (3.2 × 10−4 versus 1.76 × 10−4 cm2 V−1 s−1) as dopant-free HTM. Starlike BD HTM has a twisted acceptor unit and strong dipole, forming crystalline and ordered packing film to ensure intramolecular charge transfer and improve mobility. The BD CsPbI3 PSCs deliver the maximum efficiency of 19.19%, which is the highest performance for all-inorganic PSCs based on dopant-free HTMs. Meanwhile, the ordered molecules-packing blocks the migration channel of I− ions to metal electrodes and improves the device stability. BD-based devices maintain more than 93% and 80% of the initial efficiency after 85 °C storage for 35 days and maximum power point (MPP) tracking at 85 °C for 1000 h, respectively. |
