Self-Cleaning Perovskite Single Crystals Fabricated with Bis(trifluoromethylsulfonyl)imide Derived Ionic Liquid Toward High-Performance Photodetection

Surface defects are crucial to perovskite single crystals (SCs) for versatile optoelectronic applications, whereas suffers from the intricate post-treatments and unsatisfactory reproducibility within solution growth strategy due to the residue solvent corrosion and adsorbed precursors deposition. Here, an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMITFSI) is demonstrated, assisted solution growth approach for fabricating high-quality self-cleaning perovskite single crystals with no need for any post-treatment. Benefiting from the in situ assembling in crystalline surface, BMITFSI can effectively decrease the crystallographic trap density by simultaneously introducing the self-cleaning effect and optimizing the crystalline growth process. Particularly, as fabricated MAPbI₃ single crystal exhibits an impressive photodetection performance with a specific detectivity of 2.83 × 10¹² Jones in visible-IR spectrum and a sensitivity of 7.24 × 10⁴ µC Gy_air⁻¹ cm⁻² in X-ray detection, which is as good as the conventionally fabricated crystal with elaborate post-treatments. Based on the chemical composition independent universality, this work paves an easy but efficient route to improve the current crystallization methodology toward high-quality perovskite SCs fabrication.