Flexible Microspectrometers Based on Printed Perovskite Pixels with Graded Bandgaps

Abstract

Miniaturized spectrometers have attracted much attention due to their capability to detect spectral information within a small size. However, such technology still faces challenges including large-scale preparation and performance repeatability. In this work, we overcome these challenges by demonstrating a microspectrometer constructed with a series of pixelized graded-bandgap perovskite photodetectors fabricated with inkjet printing. High-quality perovskite films with minimal pinholes and large grains are deposited by optimizing printing conditions including substrate temperature and surface modification. The resulting perovskite photodetectors show decent photosensing performance, and the different photodetectors based on perovskite films with different bandgaps exhibit various spectral responsivities with different cutoff wavelength edges. Microspectrometers are then constructed with the array of the pixelized graded-bandgap perovskite photodetectors, and incident spectra are algorithmically reconstructed by combining their output currents. The reconstruction performance of the miniaturized spectrometer is evaluated by comparing the results to the spectral curve measured with a commercial bulky spectrometer, indicating a reliable spectral reconstruction with a resolution of around 10 nm. More significantly, the miniaturized spectrometers are successfully fabricated on polymer substrates, and they demonstrate excellent mechanical flexibility. Therefore, this work provides a flexible miniaturized spectrometer with large-scale fabricability, which is promising for emerging applications including wearable devices, hyperspectral imaging, and internet of things.

Recent progress in construction methods and applications of perovskite photodetector arrays

“…51 Huang et al fabricated a microspectrometer with a pixelated photodetector array based on the graded-bandgap CsPbX 3 perovskite, which exhibited a reliable spectral reconstruction performance with a resolution of about 10 nm. 52 So far, significant breakthroughs in perovskite-based photodetector arrays have been achieved in flexibility, large-scale integration, multispectral imaging, etc. Therefore, a review is urgently imperative to demonstrate the development of perovskite photodetector arrays.…”

“…These commonly available materials are polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polynaphthalene dimethyl ethylene glycol (PEN), textile materials, etc. 52,[118][119][120][121] Huang et al introduced a flexible 10 Â 10 perovskite photodetector array on the PI substrate by developing inkjet printing technology for color detection. 93 Each pixel with a photoconductor structure of Au/ perovskite/Au consisted of three sub-pixels.…”

Emerging Computational Micro‐Spectrometers — From Complex System Integration to Simple In Situ Modulation

“…The strong data processing software capabilities compensate for potential compromises in device performance arising from reduced hardware sizes. Table 1 , [ 16,19,24–26 ] Table 2 , [ 27–33 ] Table 3 , [ 15,34–66 ] and Table 4 [ 67–71 ] compare the performance indicators such as footprint, spectrum range and resolution of spectrometers based on conventional, mapping of spectrum to space, spectrum response modulation, and single detector strategies, respectively. Although miniaturized spectrometers based on spectrum‐to‐space mapping strategy generally achieve spectrum resolution comparable to conventional spectrometers, their footprints still cannot meet the miniaturization requirements.…”

“…Reproduced with permission. [ 64 ] Copyright 2023, American Chemical Society. d) Structurally colored silicon nanowires.…”

“…Recently, Wu et al prepared micro-spectrometers comprising gradient bandgap perovskite quantum dot photodetector arrays on flexible substrates as shown in Figure 5c. [64] This work enables the large-scale manufacture of flexible miniature spectrometers with a competitive spectrum resolution as low as 10 nm, which will considerably impact future spectrometer applications, including wearable devices, hyperspectral imaging, and the Internet of Things. [75] Although detector arrays with different performances can be constructed through bandgap engineering, the biggest disadvantage is the integrated design and that a single detector alone cannot achieve multispectral response.…”