Bulk Single Crystals of a Narrow Band Gap Three-Dimensional Hybrid Perovskitoid Enabling Ultrastable Photodetection

Motivated by the high performance of optoelectronic devices, organic–inorganic hybrid perovskites (OIHPs), particularly three-dimensional (3D) OIHPs, have taken a promising position in optoelectronic devices, owing to their high absorption coefficient, long carrier lifetime, and superior conversion efficiency. However, 3D OIHPs inevitably suffer from destruction under moisture operating conditions; it is a great struggle to synchronously realize high performance and long-term stability in optoelectronic devices. Herein, bulk single crystals (6 × 2 × 1.5 mm3) of the 3D hybrid perovskitoid (C6H10N2)Pb2Br6 (1, C6H10N22+ = N,N′-dimethyl-pyrazinium) have been grown successfully, which exhibit an excellent light absorption capacity (730 nm) and superior stability. Based on the bulk crystals of 1, photodetectors are fabricated with an extremely low dark current (3.5 pA), large current on/off ratio (>103), considerable responsivity (R, 4 mA W–1), and detectivity (D*, 4 × 1010 Jones). Strikingly, these devices possess excellent working stability (over 90 days) under ultralong air exposure, which are much better than most of the reported 3D OIHP devices. Furthermore, both experimental and computational investigations reveal that the excellent stability originates from the hydrophobic property of alkyl groups in C6H10N22+ cations. All of these results not only provide an efficient avenue to acquire 3D perovskitoid bulk single crystals but also inspire further exploration of ultrastable photoelectric devices.