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2025

Design and Development of Full-Spectrum Photodetectors

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In recent years, the rapidly developing optoelectronic industry has changed the world and extended into many aspects of life. Among them, photodetectors (PDs) with deep ultraviolet-visible-near-infrared full-spectrum detection response bandwidth play a key role in daily life as important optoelectronic components. Typically, commercial full-spectrum PDs are mainly based on traditional semiconductor materials, such as silicon (Si) based PDs for visible-near-infrared selection and indium gallium arsenide (InGaAs) based PDs for visible-shortwave infrared. However, the aforementioned PDs require complex deposition preparation processes, and the dark current and noise signals during device operation are relatively large, making the detection performance in need of further improvement. Meanwhile, due to the high light reflection coefficient and shallow ultraviolet light penetration depth of traditional semiconductor materials, it is difficult for the prepared PDs to achieve high sensitivity detection of ultraviolet light. Currently, the most mature method for preparing deep ultraviolet-visible-infrared full-spectrum PDs is mainly based on the high integration of ultraviolet PDs and visible-infrared PDs. However, issues such as system volume, cost, and differences in response capabilities of different types of PDs hinder further commercialization. Therefore, exploring and developing deep ultraviolet-visible-infrared high detection sensitivity full-spectrum PDs has become one of the research hotspots in the current field.

Research on constructing heterojunction strategies to utilize the synergistic effect of materials responsive to different wavelengths to broaden the detection range, suppress device dark current, and improve detection sensitivity has been widely reported. However, the aforementioned research mainly aims to broaden the infrared response of PDs, lacking theoretical and systematic in-depth exploration in aspects such as the interaction at the interface after constructing the heterojunction, charge transport relationships, device mechanical performance and stability, and the impact of heterojunction layer thickness on device performance. In addition, strategies that utilize fluorescent conversion materials to absorb deep ultraviolet-ultraviolet light and emit visible or infrared photons consistent with the PDs' response wavelength, thereby enhancing the device's ultraviolet detection performance, have received considerable attention.

To achieve efficient and stable deep ultraviolet-visible-near-infrared II region full-spectrum broadband response PDs, this paper mainly conducts research in the following three aspects:

1,By doping rare earth holmium ions (Ho³⁺) into CsPbI₃PQDs to improve the response performance in the visible light region and device stability (400-700 nm);

2,By combining near-infrared absorbing PbS quantum dots with the visible light layer to achieve visible-near-infrared II region wavelength response (400-1700 nm);

3,By doping rare earth ions (Ce³⁺, Yb³⁺, Er³⁺) into CsPbCl₃:Cr³⁺PQDs, achieving efficient near-infrared (900-1700 nm) quantum cutting emission with a fluorescence quantum efficiency of 179%. Further, constructing it as a fluorescent concentrator (LC) applied to the outer layer of the device achieves high-performance ultraviolet wavelength response (200-400 nm). Ultimately, the prepared PDs achieved full-spectrum response from 200-1700 nm, while the overall device detection performance exceeded 10¹²Jones, and exhibited good operational stability.

Research Highlights

a) Firstly, by doping Ho³⁺into CsPbIPQDs, through the study of the optoelectronic performance of the material, it can be concluded that Ho₃doping improves the³⁺PQDs' luminous quantum efficiency (>>93.5%) and radiative transition rate, reducing its own lattice defects, and obtaining efficient electron transport characteristics. At the same time, the ultraviolet light irradiation and thermal stability of thePQDs, through the study of the optoelectronic performance of the material, it can be concluded that Ho₃PQDs material have also been greatly improved.PQDs, through the study of the optoelectronic performance of the material, it can be concluded that Ho₃b) By combining PbS quantum dots with

PQDs, broadband light absorption from visible light to near-infrared II region (400-1700 nm) was achieved; at the same time, the luminescence intensity decreased after the combination, proving that effective charge transfer was realized between the two; further, through first-principles calculations, the accuracy of the experimental results was theoretically verified.PQDs, through the study of the optoelectronic performance of the material, it can be concluded that Ho₃c) The preparation of CsPbCl

: Cr₃, Ce³⁺PQDs for ultraviolet absorption and near-infrared quantum cutting emission fluorescent conversion materials, where³⁺, Yb³⁺, Er³⁺doping can reduceCr³⁺the defects of CsPbClPQDs itself, improving material stability;₃Ceserves as an intermediate energy level, facilitating³⁺the charge transfer fromPQDs itself, improving material stability;₃PQDs toYb³⁺, Er³⁺for better charge transfer, while it has deep ultraviolet absorption of 4f-5d, which can broaden its overall absorption to 200 nm;Yb³⁺, Er³⁺as a near-infrared light-emitting ion, achieving quantum cutting light emission from 900-1700 nm, which is then absorbed by the heterojunction layer. Preparing it in a concentrator improves the effective utilization of near-infrared light, achieving efficient ultraviolet response (200-400 nm).

d) The combination of the three achieved high sensitivity detection from 200-1700 nm, with detection responses at wavelengths of 260 nm, 460 nm, and 1550 nm reaching 3.19×10¹²Jones, 1.05×10¹³Jones, and 2.23×10¹²Jones, respectively. At the same time, the device exhibits high stability and cyclic usage characteristics.