Enhanced blue-green response of nanoarray AlGaAs photocathodes for underwater low-light detection

Crystal Violet-Loaded Bi(III)-Based Metal-Organic Framework Boosting Enhanced Photothermal Effect for Breast Cancer Treatment

Recently, metal-organic frameworks (MOFs) have emerged as promising platforms to fabricate photothermal therapeutic materials to cure tumors, but the toxic heavy metals in many MOFs may pose great threats to normal cells. In consideration of the low toxicity of bismuth, herein we made great efforts to synthesize porous bismuth-based MOFs (Bi-MOFs) to construct photothermal conversion materials for cancer treatment. By the reaction of 4,4',4''-tricarboxylic triphenylamine (H3TCA) and Bi(NO3)3 under solvothermal conditions, a porous Bi-MOF was obtained with the formula of {[Bi2(TCA)2(H2O)3]·6DMF·21H2O}n (Bi-TCA). Structural analysis revealed that complex Bi-TCA displayed a three-dimensional (3D) coordination framework featuring abundant accessible channels and cages with a porosity of 73.3% according to the calculating results of PLATON. Due to the high porosity, complex Bi-TCA could effectively encapsulate the dye crystal violet (CV) into the voids and the resulting dye-loaded composite CV@Bi-TCA exhibited extended red-shifted light-absorbing property and enhanced photothermal conversion capability under 455 nm laser irradiation. Further anticancer experiments demonstrated that composite CV@Bi-TCA could efficiently inhibit the growth of breast cancer cells both in vitro and in vivo under 455 nm laser irradiation. This work may promote investigations on the low-toxicity Bi-MOFs for photothermal cancer therapy.

Quantitative study on the photoemission of AlGaN nanoarrays based on the three-dimensional transportation within a four-step process

Photocathodes play a crucial role in photoelectronic imaging and vacuum electronic devices. The quantum efficiency of photocathodes, which determines their performance, can be enhanced through materials engineering. However, the quantum efficiency of conventional planar photocathodes remains consistently low, at around 25%. In this paper, we propose what we believe is a novel structure of AlGaN nanowire array to address this issue. We investigate the photoemission characteristics of the nanowire array using the "four-step" process, which takes into account optical absorption, electron transportation, electron emission, and electron collection. We compare the quantum efficiency of nanowire arrays with different structure sizes and Al components. After studying the effect of incident light at various angles on the nanowire array photocathode, we identify the optimal dimensional parameters: a height of 400∼500 nm and a wire width of 200∼300 nm. Furthermore, we improved the collection efficiency of the photocathode by introducing a built-in/external electric field, and obtained a 104.4% enhancement of the collection current with the built-in electric field, meanwhile the photocurrent was increased by 87% compared to the case without the external electric field. These findings demonstrate the potential of optimizing photocathode performance through the development of a novel model and adjustment of parameters, offering a promising approach for photocathode applications.