Dual narrowband photodetectors based on halide perovskite single crystal heterojunctions with solution-processed epitaxial growth

Abstract

Dual-band photodetectors (PDs), which can sense two specific bands simultaneously or alternately, have great applications in spectral analysis, imaging, optical communication, and so on. However, some studies on dual-band PDs are mostly limited by drawbacks such as high cost, fixed dual-band range, and lattice mismatches between interfaces. Herein, we propose organic–inorganic halide perovskite single crystal heterojunctions (PSCHs) for dual-band detection via solution-processed epitaxial growth, with a structure of bismuth doped MAPbCl₃/intrinsic MAPbBr_xCl_3−x/bismuth doped MAPbI_yBr_3−y/intrinsic MAPbI_zBr_3−z (where x, y, and z are between 0 and 1). The peak position and the full-width at half maximum (FWHM) value of dual-band PDs can be adjusted by changing the proportion of halide in the perovskite single crystal layers in the device, achieving different dual-band spectral response ranges. Eventually, a device exhibits two farthest peaks at 465 nm and 820 nm of visible (Vis)/near-infrared (NIR) range with the corresponding FWHM values of 22.6 nm and 19.4 nm under 2 V. The PSCH-based device can be called dual narrowband PD exhibiting good stability and a response speed of hundreds of microseconds, attributed to the small lattice mismatch and heterostructure. It also shows a high spectral rejection ratio (∼360). In conclusion, this article proposes an approach for customizing dual narrowband PDs with tunable spectral response ranges based on solution-processed epitaxial growth.