Highly sensitive UVA and violet photodetector based on single-layer graphene-TiO2 heterojunction.

A highly sensitive ultraviolet A (UVA) and violet photodetector based on p-type single-layer graphene (SLG)-TiO2 heterostructure was fabricated by transferring chemical vapor deposition derived SLG on the surface of commercial single-crystal TiO2 wafer. Optoelectronic analysis reveals the as-fabricated Schottky junction PD was highly sensitive to light illumination in UVA and violet range, with peak sensitivity at 410 nm and excellent stability and reproducibility, but virtually blind to illumination with wavelength less than 350 nm or more than 460 nm. The on/off ratio of the device was calculated to be 6.8 × 104, which is better than the majority of previously reported TiO2 based PDs. What is more, the rise/fall time were estimated to be 0.74/1.18 ms, much faster than other TiO2 based counterparts. The totality of the above result signifies that the present SLG-TiO2 Schottky junction photodetector may have promising application in future high-speed, high-sensitivity optoelectronic nanodevices and systems.

Rhodium catalyzed C-C bond cleavage/coupling of 2-(azetidin-3-ylidene)acetates and analogs.

The C-C bond cleavage/coupling of 2-(azetidin-3-ylidene)acetates with aryl boronic acids catalyzed by a rhodium complex was studied with a "conjugate addition/ß-C cleavage/protonation" strategy.

High-Performance Red-Light Photodetector Based on Lead-Free Bismuth Halide Perovskite Film.

In this study, we developed a sensitive red-light photodetector (RLPD) based on CsBi3I10 perovskite thin film. This inorganic, lead-free perovskite was fabricated by a simple spin-coating method. Device analysis reveals that the as-assembled RLPD was very sensitive to 650 nm light, with an on/off ratio as high as 105. The responsivity and specific detectivity of the device were estimated to be 21.8 A/W and 1.93 × 1013 Jones, respectively, which are much better than those of other lead halide perovskite devices. In addition, the device shows a fast response (rise time: 0.33 ms; fall time: 0.38 ms) and a high external quantum efficiency (4.13 × 103%). It is also revealed that the RLPD has a very good device stability even after storage for 3 months under ambient conditions. In summary, we suggest that the CsBi3I10 perovskite photodetector developed in this study may have potential applications in future optoelectronic systems.

Graphene-ß-Ga2 O3 Heterojunction for Highly Sensitive Deep UV Photodetector Application.

A deep UV light photodetector is assembled by coating multilayer graphene on beta-gallium oxide (ß-Ga2 O3 ) wafer. Optoelectronic analysis reveals that the heterojunction device is virtually blind to light illumination with wavelength longer than 280 nm, but is highly sensitive to 254 nm light with very good stability and reproducibility.

Broadband photodetector based on carbon nanotube thin film/single layer graphene Schottky junction.

In this study, we present a broadband nano-photodetector based on single-layer graphene (SLG)-carbon nanotube thin film (CNTF) Schottky junction. It was found that the as-fabricated device exhibited obvious sensitivity to a wide range of illumination, with peak sensitivity at 600 and 920 nm. In addition, the SLG-CNTF device had a fast response speed (τr = 68 µs, τf = 78 µs) and good reproducibility in a wide range of switching frequencies (50-5400 Hz). The on-off ratio, responsivity, and detectivity of the device were estimated to be 1 × 102, 209 mAW-1 and 4.87 × 1010 cm Hz1/2 W-1, respectively. What is more, other device parameters including linear performance θ and linear dynamic range (LDR) were calculated to be 0.99 and 58.8 dB, respectively, which were relatively better than other carbon nanotube based devices. The totality of the above study signifies that the present SLG-CNTF Schottky junction broadband nano-photodetector may have promising application in future nano-optoelectronic devices and systems.