In Situ Formed Gradient Bandgap‐Tunable Perovskite for Ultrahigh‐Speed Color/Spectrum‐Sensitive Photodetectors via Electron‐Donor Control

Sun, Haoxuan; Tian, Wei; Wang, Xianfu; Deng, Kaiming; Xiong, Jie; Li, Liang

doi:10.1002/adma.201908108

Cited by 70 publications

(66 citation statements)

References 48 publications

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“…Such localized patterns of bandgap gradients possess major potential applications, including multicolour LEDs and complex designs of colour sensors. In addition to the rainbow perovskite, the device can also be obtained by using various compositionally graded semiconductors (such as Si 1− x Ge x (0.7–1.1 eV), V x Zn y O (0.6–3.3 eV), ZnO x N y (1.0–3.3 eV), In x Ga 1− x N (0.7–3.4 eV), and CdS x Se 1− x (1.7–2.4 eV)), multiple device configurations (including semiconductor films with vertical bandgap-gradient distributions, conducting films blended with bandgap-gradient semiconductor nanoparticles, and semiconductor nanowires with axial GBGs) and different fabrication technologies 14 , 15 , 39 – 42 , which can lead to a variety of device characteristics. For instance, arrays of devices with high photon energy responsivity can be obtained by using conducting films blended with bandgap-gradient CsPbX 3 quantum dots 43 .…”

Section: Discussionmentioning

confidence: 99%

“…x Se 1−x (1.7-2.4 eV)), multiple device configurations (including semiconductor films with vertical bandgap-gradient distributions, conducting films blended with bandgap-gradient semiconductor nanoparticles, and semiconductor nanowires with axial GBGs) and different fabrication technologies 14,15,[39][40][41][42] , which can lead to a variety of device characteristics. For instance, arrays of devices with high photon energy responsivity can be obtained by using conducting films blended with bandgap-gradient CsPbX 3 quantum dots 43 .…”

Section: Ev) and Cdsmentioning

confidence: 99%

“…Thus, none of the existing photodetectors are able to provide spectral information at the device level. It was recently reported that integrating dozens or hundreds of photodetectors with semiconductors presenting different bandgaps can reconstruct the spectral curves of incident light 14 , 15 . Nevertheless, such an approach already requires a chip-level device assembly and signal-processing system, and can generate redundant signals for applications that do not need detailed spectral information.…”

Section: Introductionmentioning

confidence: 99%

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Spectrum projection with a bandgap-gradient perovskite cell for colour perception

Zhang

Riaud

et al. 2020

Light Sci Appl

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Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications, including sensing, imaging, optical communications, and in situ characterization. However, existing photodetectors indicate only light intensities, whereas multiphotosensor spectrometers require at least a chip-level assembly and can generate redundant signals for applications that do not need detailed spectral information. Inspired by human visual and psychological light perceptions, the compression of spectral information into representative intensities and colours may simplify spectrum processing at the device level. Here, we propose a concept of spectrum projection using a bandgap-gradient semiconductor cell for intensity and colour perception. Bandgap-gradient perovskites, prepared by a halide-exchanging method via dipping in a solution, are developed as the photoactive layer of the cell. The fabricated cell produces two output signals: one shows linear responses to both photon energy and flux, while the other depends on only photon flux. Thus, by combining the two signals, the single device can project the monochromatic and broadband spectra into the total photon fluxes and average photon energies (i.e., intensities and hues), which are in good agreement with those obtained from a commercial photodetector and spectrometer. Under changing illumination in real time, the prepared device can instantaneously provide intensity and hue results. In addition, the flexibility and chemical/bio-sensing of the device via colour comparison are demonstrated. Therefore, this work shows a human visual-like method of spectrum projection and colour perception based on a single device, providing a paradigm for high-efficiency spectrum-processing applications.

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Section: Discussionmentioning

confidence: 99%

Section: Ev) and Cdsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectrum projection with a bandgap-gradient perovskite cell for colour perception

Zhang

Riaud

et al. 2020

Light Sci Appl

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“…© 2020 Wiley-VCH GmbH bandgap. [116] The unique composition of the perovskite film was realized by deposition between a temperature gradient from -20 °C to 210 °C. Encouragingly, a nanosecond response speed is achieved in all the ingredient photodetectors due to improved junction capacitance (vide supra).…”

Section: (14 Of 23)mentioning

confidence: 99%

Miscellaneous and Perspicacious: Hybrid Halide Perovskite Materials Based Photodetectors and Sensors

Tsao

Zhang

et al. 2020

Advanced Optical Materials

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abbreviated as AMX 3 (A is an organic cation, e.g., CH 3 NH 3 + , HN=CHNH 3 + ; M is a metal cation, e.g., Sn 2+ , Pb 2+ ; X is a halide anion, e.g., Cl − , Br − , I −). In their crystal framework, corner-sharing BX 6 octahedrons form the 3D network with the A cations situated in the cuboctahedral interstices. [4,5] The inorganic components of the halide perovskite provide the conductive backbones required by the carrier's ordered transmission and also provide the thermal and mechanical stability of the material. The organic components, on the other hand, function as templates via hydrogen bonds during the perovskite film formation process. Different from 3D perovskites, layer-structured 2D perovskite materials follow the (RNH 3) 2 (A 3) n-1 M n X 3n+1 structure, where R is an alkyl or aromatic moiety larger than A, and n is the number of inorganic layers between the organic chains. [6,7] When n→∞, the structure converts to 3D perovskite. When n is a limited integer, quantum well structures form with layers of AX 4 2− separated and supported by a layer of organic cations via weak van der Waals forces. The inorganic components provide high carrier mobility and wide bandgap tunability. The organic components, being either large aliphatic or aromatic ammonium cations, can enhance hydrophobicity by preventing water molecules from penetrating and destroying the inorganic layers. Thus 2D perovskites usually demonstrate improved environmental stability against moisture. [8-10] Importantly, 2D perovskite crystals also showed unique optical properties such as deep blue emission and strong excitonic effect due to the strong quantum well effect. [11] Furthermore, targeting on the instability issue of hybrid perovskites under high-temperature and humid environments, scientists prompted all-inorganic perovskites (e.g., CsPbX 3) by replacing the organic component with inorganic ions. [12] Besides the rapid development of perovskite-based photovoltaics, [13-16] other perovskite-related devices including lightemitting diodes (LED), [17-20] laser, [21-23] transistors, [24] thermoelectric generators, [25] photodetectors for UV-NIR photons, [26-29] and various sensors for gas, chemical, and pressure have been widely studied. [30-33] Among all these potential applications, detectors and sensors became very active areas of research and even the third-largest application behind photovoltaics and LEDs (Figure 1). This trend could, again, be attributed to the favorable intrinsic properties of hybrid halide perovskites such as direct and tunable bandgaps with significant absorption coefficients, ultralong charge carrier lifetimes/diffusion lengths, high carrier mobilities, low charge carrier recombination, broad Optoelectronic devices based on perovskite materials have shown significant improvement due to the direct and tunable bandgaps, large absorption coefficients, broad absorption spectra, high carrier mobilities, and long carrier diffusion lengths. In addition to the excellent performance in solar cells, scientists have utilized per...

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“…For this reason, by combining with wave destructive interference, we introduce the design concept of GRIN PnCs to overcome the shortcomings of bandgap structure with a narrow frequency range. A similar method using gradient design to overcome narrow bandgaps can be found in Wang et al and Sun et al [34,36] However, with the gradient index, unlike the previous GRIN PnCs, we extend the original concept of gradient refractive index to the functionally graded structure, that is, the gradient arrangement of unit cells with different bandgaps. The remainder of this article is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

Functionally Graded Phononic Crystals with Broadband Gap for Controlling Shear Wave Propagation

Liu

Yoon

et al. 2020

Adv Eng Mater

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Metamaterials that can be used in manipulating wave propagation have been shown in previous research. However, existing methods for controlling the propagation of shear waves remain a challenge. By combining the principle of wave destructive interference and the design concept of the gradient‐index phononic crystals, here new functionally graded phononic crystals with broadband gap for controlling shear wave propagation are presented. The proposed functionally graded phononic crystals are formed by an array of unit cells with different topological geometries, where the topological geometries of the unit cell are tailored to obtain the frequency bandgap guided by the wave destructive interference. Meanwhile, the frequency bandgap with a target width is obtained by combining the design concept of the gradient‐index phononic crystals. This work presents an approach to control the propagation of shear waves, and the advantages of the method reported in this work can be useful in engineering applications, such as bridges, railways, and buildings.

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In Situ Formed Gradient Bandgap‐Tunable Perovskite for Ultrahigh‐Speed Color/Spectrum‐Sensitive Photodetectors via Electron‐Donor Control

Cited by 70 publications

References 48 publications

Spectrum projection with a bandgap-gradient perovskite cell for colour perception

Spectrum projection with a bandgap-gradient perovskite cell for colour perception

Miscellaneous and Perspicacious: Hybrid Halide Perovskite Materials Based Photodetectors and Sensors

Functionally Graded Phononic Crystals with Broadband Gap for Controlling Shear Wave Propagation

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