Epitaxial Perovskite Single-Crystalline Heterojunctions for Filter-Free Ultra-Narrowband Detection with Tunable Spectral Responses

Abstract

Narrowband photodetectors (NPDs) with the capability of detecting light within a selective wavelength range are in high demand for numerous emerging applications such as imaging systems, machine vision, and optical communication. Halide perovskite materials have been developed for eliminating the current complex filtering systems in NPDs due to their beneficial properties, while currently NPDs using perovskite materials are limited by hardly fully eliminated short wavelength response, low charge collection efficiency (CCE), complex fabrication process, and so forth. Herein, a series of perovskite single-crystalline heterojunctions (PSCHs) with a structure of Bi-MAPbX3/MAPbY3 are fabricated by liquid phase epitaxy for filter-free narrowband detection. By varying the halide component in the PSCH, the PSCH-based NPDs can realize continuously tunable spectral response range from blue to NIR regions and ultra-narrow full width at half-maximum (FWHM) of <20 nm. Specifically, the PSCH-based NPD with a high CCE under a large electric filed shows a high spectra rejection ratio of >1000, a fast response speed with rise/fall time of ∼160/∼225 μs, and long-term stability more than 3 months in ambient air. This work provides a simple strategy for designing low-cost and high-performance filter-free NPDs with a tunable spectral response.

Quasi-Tandem Photodetector with Tunable Narrowband Response and Submicrosecond Response Time: Charge-Selected Transmitting Narrowing

“…This can be attributed to the extraction of a small number of carriers near the electrode. Previously used strategies have been found to be less effective in terms of response time than the strategy reported herein. ,,, Figure b illustrates the process of achieving a narrowband response in the presence of a thick active layer. The thickness of the perovskite layer increased gradually from 0 (without) to 1700 nm when the thickness of the organic blend was kept unchanged, resulting in the gradual generation of a narrowband spectral response.…”

Visible-Blind Narrowband Near-Infrared Photodetector for Precise Real-Time Photoplethysmography Measurement

“…The EQE max value is one of the highest ones among the NIR NPDs ever reported (Table S3). ,,,− Although the thick perovskite layer weakens the intensity of incident NIR light (Figure S5), the maximum EQE values in the NIR region of PD-Br-IT4F present almost the same NIR response as the PM6:IT4F-based OPD. PD-MA-Y6 and PD-FA-C9 even present higher NIR EQE values than the corresponding OPDs (Figure S12).…”

Visible Elimination, Ultraviolet and Near-Infrared Dual-Band Photodetector Based on Single-Crystal Perovskite Heterojunctions Toward Secure Optical Communication

“…As a class of equipment with the ability to convert optical signals into electrical signals, photodetectors (PDs) are crucial components in modern optical-electrical interconnect systems, such as optical communication, digital imaging, remote sensing, medical and biological analysis, etc. The present commercially available PDs based on mature semiconductors as sensitive layers, such as silicon and some compounds (InGaAs, HgCdTe, ZnO...), belong to broadband photodetectors (BPDs), which are sensitive to a wide range of wavebands corresponding to their absorption spectra. − Some PDs have the ability to selectively detect a specific range of wavebands and belong to narrowband photodetectors (NPDs) by adopting various strategies, including adding dedicated bandpass filters, using narrowband absorbing photoactive materials, microcavity structure design, , charge collection narrowing concept, , charge injection narrowing concept, , and heterostructure PD design. − However, traditional BPDs and NPDs still hardly satisfy the needs of application scenarios. Because BPDs may face severe signal interference due to their response to a wide range of wavelengths of light outside of the desired detection band, using NPD responding only to a single waveband may face the risk of signal leakage if the wavelength of the propagating signal is leaked .…”

“…One of the important issues to realize dual-band detection using perovskite as a photosensitive layer is how to eliminate photoelectric response out of the target detection waveband. The incorporation of bismuth ions into perovskites will change their optical and electrical properties due to the introduction of defects, − which has been proven to be an efficient way to adjust the photoelectric response of perovskite based PDs. , …”

“…The incorporation of bismuth ions into perovskites will change their optical and electrical properties due to the introduction of defects, 37−39 which has been proven to be an efficient way to adjust the photoelectric response of perovskite based PDs. 15,40 Herein, we developed a novel perovskite single crystal heterojunction (SCPH), which tandem vertically combined four different bandgap single-crystalline perovskite layers (pristine MAPbCl 3 , Bi 3+ doped MAPbBr 3 , Bi 3+ doped MAPbI 2.5 Br 0.5 , and pristine MAPbI 3 ) without serious lattice mismatch between different perovskite layers, through a facile and low-cost liquid-phase epitaxial (LPE) method proposed in our previous works. 15,41−43 Attributed to the well-designed energy band engineering and discontinuous electric field distribution in the SCPH, we successfully obtained broad UV and narrow NIR dual-band spectral response detectors with visible waveband response elimination.…”