Calcium Titanate Orthorhombic Perovskite-Nickel Oxide Solar-Blind UVC Photodetectors with Unprecedented Long-Term Stability Exceeding 500 Days and Their Applications to Real-Time Flame Detection

In recent years, the rapid increase in fire frequency has led to demands for efficient fire monitoring systems. To realize sensitive and large-area fire monitoring, flame sensing based on an ultraviolet C (UVC) photodetector can be considered as a promising approach. However, the challenges such as the high-cost process, limited selection of photoactive materials with an appropriate band gap, inefficient power consumption, stability issues, and environmental noise interference restrict the development of UVC photodetectors (PDs) for practical flame safeguard applications. Here, we demonstrate flame detection with a UVC PD based on an ultrawide band gap calcium titanate (CTO) and nickel oxide (NiO) heterostructure. The proposed PD achieves a high solar-blinded rejection ratio (at UVC light/UVA light) of 2.9 × 104, on/off switching current ratio of 120 A/A under UVC light and dark state, robust and stable operation longer than 1 year (502 days), and specific detectivity as high as 4.44 × 1011 Jones under zero-voltage bias operation. During the flame combustion, the CTO/NiO UVC PD exhibits a systematic real-time output voltage change with flame intensity variation, which opens up new possibilities for rapid and accurate fire detection

Calcium Titanate Orthorhombic Perovskite-Nickel Oxide Solar-Blind UVC Photodetectors with Unprecedented Long-Term Stability Exceeding 500 Days and Their Applications to Real-Time Flame Detection

In recent years, the rapid increase in fire frequency has led to demands for efficient fire monitoring systems. To realize sensitive and large-area fire monitoring, flame sensing based on an ultraviolet C (UVC) photodetector can be considered as a promising approach. However, the challenges such as the high-cost process, limited selection of photoactive materials with an appropriate band gap, inefficient power consumption, stability issues, and environmental noise interference restrict the development of UVC photodetectors (PDs) for practical flame safeguard applications. Here, we demonstrate flame detection with a UVC PD based on an ultrawide band gap calcium titanate (CTO) and nickel oxide (NiO) heterostructure. The proposed PD achieves a high solar-blinded rejection ratio (at UVC light/UVA light) of 2.9 × 104, on/off switching current ratio of 120 A/A under UVC light and dark state, robust and stable operation longer than 1 year (502 days), and specific detectivity as high as 4.44 × 1011 Jones under zero-voltage bias operation. During the flame combustion, the CTO/NiO UVC PD exhibits a systematic real-time output voltage change with flame intensity variation, which opens up new possibilities for rapid and accurate fire detection

Calcium Titanate Orthorhombic Perovskite-Nickel Oxide Solar-Blind UVC Photodetectors with Unprecedented Long-Term Stability Exceeding 500 Days and Their Applications to Real-Time Flame Detection

In recent years, the rapid increase in fire frequency has led to demands for efficient fire monitoring systems. To realize sensitive and large-area fire monitoring, flame sensing based on an ultraviolet C (UVC) photodetector can be considered as a promising approach. However, the challenges such as the high-cost process, limited selection of photoactive materials with an appropriate band gap, inefficient power consumption, stability issues, and environmental noise interference restrict the development of UVC photodetectors (PDs) for practical flame safeguard applications. Here, we demonstrate flame detection with a UVC PD based on an ultrawide band gap calcium titanate (CTO) and nickel oxide (NiO) heterostructure. The proposed PD achieves a high solar-blinded rejection ratio (at UVC light/UVA light) of 2.9 × 104, on/off switching current ratio of 120 A/A under UVC light and dark state, robust and stable operation longer than 1 year (502 days), and specific detectivity as high as 4.44 × 1011 Jones under zero-voltage bias operation. During the flame combustion, the CTO/NiO UVC PD exhibits a systematic real-time output voltage change with flame intensity variation, which opens up new possibilities for rapid and accurate fire detection

Calcium Titanate Orthorhombic Perovskite-Nickel Oxide Solar-Blind UVC Photodetectors with Unprecedented Long-Term Stability Exceeding 500 Days and Their Applications to Real-Time Flame Detection

In recent years, the rapid increase in fire frequency has led to demands for efficient fire monitoring systems. To realize sensitive and large-area fire monitoring, flame sensing based on an ultraviolet C (UVC) photodetector can be considered as a promising approach. However, the challenges such as the high-cost process, limited selection of photoactive materials with an appropriate band gap, inefficient power consumption, stability issues, and environmental noise interference restrict the development of UVC photodetectors (PDs) for practical flame safeguard applications. Here, we demonstrate flame detection with a UVC PD based on an ultrawide band gap calcium titanate (CTO) and nickel oxide (NiO) heterostructure. The proposed PD achieves a high solar-blinded rejection ratio (at UVC light/UVA light) of 2.9 × 104, on/off switching current ratio of 120 A/A under UVC light and dark state, robust and stable operation longer than 1 year (502 days), and specific detectivity as high as 4.44 × 1011 Jones under zero-voltage bias operation. During the flame combustion, the CTO/NiO UVC PD exhibits a systematic real-time output voltage change with flame intensity variation, which opens up new possibilities for rapid and accurate fire detection

Role of Graphene in Reducing Fatigue Damage in Cu/Gr Nanolayered Composite

Nanoscale metal/graphene nanolayered composite is known to have ultrahigh strength as the graphene effectively blocks dislocations from penetrating through the metal/graphene interface. The same graphene interface, which has a strong sp2 bonding, can simultaneously serve as an effective interface for deflecting the fatigue cracks that are generated under cyclic bendings. In this study, Cu/Gr composite with repeat layer spacing of 100 nm was tested for bending fatigue at 1.6% and 3.1% strain up to 1,000,000 cycles that showed for the first time a 5–6 times enhancement in fatigue resistance compared to the conventional Cu thin film. Fatigue cracks that are generated within the Cu layer were stopped by the graphene interface, which are evidenced by cross-sectional scanning electron microscopy and transmission electron microscopy images. Molecular dynamics simulations for uniaxial tension of Cu/Gr showed limited accumulation of dislocations at the film/substrate interface, which makes the fatigue crack formation and propagation through thickness of the film difficult in this materials system

Additional file 1 of Exploring shared neural substrates underlying cognition and gait variability in adults without dementia

Additional file 1: Figure S1. Cortical thickness and gait variability in older adults with MCI (n = 39)