Air Induced Formation of Cs₃Bi₂Br₉/Cs₃BiBr₆ Bulk Heterojunction and Its Dual‐band Photodetection Abilities for Light Communication

Abstract

Metal-halide perovskites have long carrier diffusion lengths, low trap densities, and high carrier mobilities, and are therefore of value in the development of photodetectors (PDs). However, the research on dual-band lead-free perovskite bulk heterojunction has not been well developed. Here, a novel air induced formation of Cs 3 Bi 2 Br 9 /Cs 3 BiBr 6 bulk heterojunction, reaching a high-performance dual-band photodetecting performance with an ultraviolet main band (360 nm) peak responsivity of 5.6 mA W −1 and a blue sub-band (450 nm) peak responsivity of 0.6 mA W −1 at 2 V, is reported. The bulk heterojunction exhibits superior photodetecting performance than that of lateral heterojunction. Furthermore, the PD exhibits a fast response speed (rise time 1.4 µs and decay time 2.0 µs) and good cyclic stability. Theoretical and experimental characterizations suggest Cs 3 Bi 2 Br 9 exhibits a more stable structure in air than that of Cs 3 BiBr 6 . The dual-band photodetection abilities of Cs 3 Bi 2 Br 9 /Cs 3 BiBr 6 bulk-heterojunction demonstrate great application prospects in light communication. These state-of-the-art findings shed light on the fabrication of novel dual-band high-performance PDs based on leadfree perovskite bulk-heterojunction.

Photoimaging with Color-Sensing Abilities by Tuning the Band Gap of a Single-Crystal Lead-Free Perovskite

“…A total of 1 μL of the solution was transferred to the center of the glass, which was covered by the target substrate. The growth temperature was maintained at 70 °C for 24 h. The detailed fabrication process is given in Figure b and our previous report …”

“…The growth temperature was maintained at 70 °C for 24 h. The detailed fabrication process is given in Figure 1b and our previous report. 6 2.2. Characterization of MA 3 Bi 2 I 3x Br 9−3x (x = 0, 1, 2, and 3).…”

“…With the development of modern society, automatic driving and object interaction play an increasingly important role in today’s scientific and technological life. , Therefore, it is necessary to develop sensors with multiple functionalities to satisfy our daily demands. Photodetectors (PDs), as one of the most important sensors that can convert light signals to electric signals, have aroused great interest due to their applications in fields such as information exchange, space exploration, imaging, and so forth. − PDs with different functionalities have been well developed; for example, dual-band PDs have been fabricated for light communication, and ultraviolet (UV) PDs have been fabricated for imaging, issuing UV warnings, and wide-angle field-of-view cameras. − Yet, little research has been conducted on PDs with color-recognition abilities. Commercial Si PDs realized color-sensing abilities but require expensive filters or complex algorithms.…”

Recent Progress on Wavelength‐Selective Perovskite Photodetectors for Image Sensing

“…Recently, Fang et al reported dual-band PDs by using Cs 3 Bi 2 Br 9 /Cs 3 BiBr 6 perovskite bulk heterojunction. [89] The device presented two spectral response peaks located at 360 and 450 nm, with responsivities of 59.4 and 3.09 mA W −1 , respectively. Remarkably, this device exhibited excellent optoelectronic performances in the UV band, including high detectivity of 1.2 × 10 12 Jones, a high on/off current ratio of 18 881, and a fast response speed (rise and fall times: 1.4 and 2 μs), respectively.…”

FACILE AND CONTROLLED SYNTHESIS OF 2D ORGANOMETAL HALIDE PEROVSKITE PURE BA2MAPb2I7 AND HETEROSTRUCTURED BA2PbI4/BA2MAPb2I7 SINGLE CRYSTALS

“…Nowadays, researchers have succeeded in synthesizing various 2D perovskite heterostructures such as (BA) [16]. Moreover, 2D OHP single-crystal heterostructures are of great importance for dual-band high-performance photodetectors due to the tunable optical bandgap allowing high absorption coefficients over multiple spectral regions [15,17]. It is of great importance to synthesize high-quality 2D OHP pure single crystals and their heterostructures instead of widely used polycrystalline films for higher detector performances [15].…”