Upconverting Near‐Infrared Light Detection in Lead Halide Perovskite with Core–Shell Lanthanide Nanoparticles

Abstract

Human eyes cannot detect near-infrared (NIR) light in the wavelength region of 780-2500 nm. As NIR light can penetrate many substances and is safe for the human body unlike X-ray and UV light, it is used routinely in various applications such as infrared cameras for night vision, infrared or wireless communication, optical fibers, remote controls, and biometric authentication. [1][2][3][4] Therefore, highly sensitive detection of light in the NIR region is indispensable for the advancement of optical communication technologies, medical diagnosis, and environmental measurement. Compound semiconductor devices (e.g., InGaAs with an absorption band of 900-1700 nm) have been used mainly for light detection in the NIR region. [5][6][7][8][9] However, the technology for detecting NIR light has not yet reached the accuracy of visible light detection using Si-based devices. This is because existing materials for NIR detection have the small bandgap for NIR absorption and increase dark current (noise). Therefore, these materials are fundamentally more difficult to detect light with high sensitivity than visible light detecting materials like Si.Recently, the development of photodetectors based on lead halide perovskite materials, which exhibit excellent optical absorption properties and can be deposited by a wet process, [10] has been proceeding actively. More sensitive photodetection in the visible wavelength region comparable to Si has been reported. [11][12][13][14][15] However, only a limited region of light (i.e., <800 nm visible light) can be detected due to the bandgap in these materials. It is possible to extend the detection wavelength to the NIR region by replacing Pb 2þ with Sn 2þ to narrow the bandgap; [16][17][18][19][20] however, many issues such as significant decrease in thermal stability and lower photoelectric conversion efficiency in tin-than lead-based devices have been encountered.In this study, a new NIR detection method for lead halide perovskites by the use of upconversion (UC) materials, which can convert NIR light to visible light, is presented. High optical absorption coefficients (10 5 cm À1 ) of lead halide perovskites enable efficient detection of visible light on perovskite-based photodetectors. Therefore, the detection of weak NIR signals in perovskite-based photodetectors would be possible if the energy transfer from UC materials to perovskite occurs after NIR light irradiation. The occurrence of energy transfer from UC materials to perovskites has been demonstrated in the previous reports. Pérez-Prieto et al. showed the first example of an energy transfer from the UC to the perovskite in the UC-perovskite nanohybrid, in which perovskite nanoparticles (NPs) anchored at about 1 nm from the UC NPs (UCNPs) surface by means of a macromolecule (cucurbituril). [21] They also reported that the sensitized emission

Parallel Diffractive Multi‐Beam Pulsed‐Laser Ablation in Liquids Toward Cost‐Effective Gram Per Hour Nanoparticle Productivity

“…[22] Producing NPs with a surfactant-free surface is a highly desirable property in the field of biomedicine and catalysis [27] as the surface composition of the NPs strongly influences the biocompatibility and the cytotoxicity of the NPs, [28] the specific surface area of the nanocatalysts, [2,10,29,30] and generally the active surface sites for light conversion, harvesting, and sensing. [31][32][33] In addition, PLAL complies with the green chemistry principles [34] compared to chemical synthesis routes as it is performed in an ambient atmosphere, requires less or no hazardous solvents and chemicals, produces less waste, and favors efficient reactant employment (atom economy). [35] Despite the advantages offered by PLAL, its industrial use is still limited due to the low production rate compared to the chemical synthesis routes.…”