Hybrid halide perovskite solar cells (PSCs) have enormous potential to provide energy for future space exploration and aerospace due to their unique advantages in harsh environments. Unfortunately, it is challenging to fabricate robust PSCs that are insensitive to low temperatures. This study presented the performance evolution of methylammonium triiodide (MAPbI 3 ) PSCs across a temperature range of 290 to 90 K and highlighted the decisive impact of interfacial defects on the devices’ low-temperature performance. The introduction of polymethyl methacrylate (PMMA) as interface modification layer, efficiently passivated the interface defects, released the interfacial stress, and thus decreased the phase transition temperature. As a result, the PMMA-modified device achieved a maximum efficiency of 22.4% at 90 K which was one of the highest efficiencies reported for MA-based PSCs at low temperatures. Remarkably, the PMMA-modified device retained nearly 100% of initial efficiency after 26 temperature cycling tests between 290 and 90 K, whereas the control device maintained only 62% of initial efficiency. This work demonstrated that interface engineering is a promising strategy for improving the low-temperature performance of PSCs.
Mengyuan Liu,Le Ma,Kehan Xie,Piaopiao Zeng,Shijing Wei,Feng Zhang,Chao Li,Feijiu Wang
Cesium lead halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) have attracted enormous attention because of their great potential for optoelectronic applications, such as light-emitting diodes (LEDs). However, the photoluminescence and surface ligands of CsPbX3 NCs have a great impact on their device applications. Herein, we report a molecular superacid of bis(trifluoromethane)sulfonimide (TFSI), which could boost the photoluminescence in the metal halide perovskite nanocrystals. In particular, the photoluminescence quantum yield (PLQY) of CsPbI3 nanocrystals could be greatly improved from 28.6% to near 100% with the superacid treatment. The improved PLQY in CsPbX3 nanocrystals is mainly contributed from the surface passivation based on the characterizations. The CsPbX3 nanocrystals were further modified with PMMA, which could greatly improve their stability while preserving high photoluminescence and good dispersion. The use of superacid combined with a polymer for improving the photoluminescence and stability in CsPbX3 provides an alternative strategy for optoelectronics.