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Photoelectrochemical (PEC) sensors have emerged as a promising candidate for biochemical detection. However, PEC sensors based on bulk semiconductors are limited by sensitivity and detection varieties, though they can provide uniform imaging; PEC sensors based on nanomaterials can meet the requirements of various analytes and sensitivity, but the inhomogeneity of their surface poses a challenge to imaging uniformity. In this work, metal-assisted chemical etching (MACE) and sputtering processes were used to directly fabricated PEC sensors with fireworks-like silicon nanowires (F-SiNWs) and their heterojunctions with excellent performance. Through regulating the etching and sputtering times, the structure and nanomaterials attachment of F-SiNWs can be well controlled. The photoelectric and sensing properties of F-SiNWs with different morphologies were investigated and optimized. Then, the sensor fabricated by optimal F-SiNWs can directly detect H 2 O 2 and indirectly detect glucose under negative bias, while directly detect dopamine (DA) under positive bias. The detection of these three analytes do not interfere with each other, contributing to an excellent multichannel detection system. Subsequently, the multichannel detection of various secretions (H 2 O 2 , DA and glucose) of PC-12 cells was achieved by the sensor. Finally, the imaging uniformity of the sensor was demonstrated in different solutions. PEC bioimaging was successfully applied to monitor enzyme activity by bioimaging gradients and cell survival by bioimaging distribution. These results demonstrate the high sensitivity in multichannel detection and excellent stability and homogeneity in bioimaging of the sensor. Therefore, MACE and sputtering process can be a promising tool for constructing PEC sensor. • MACE and sputtering processes were used for fabricating highly sensitive PEC sensor. • The structure of F-SiNWs/Ag was optimized by the etching and sputtering time. • The mechanism of MACE and sputtering processes enhancing PEC performance was studied. • Multichannel detection of H 2 O 2 , DA and glucose secreted by PC-12 cells was achieved. • PEC sensor achieved uniform bioimaging to study enzyme activity and cell survival. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) additive manufacturing, as a novel technique provides broad benefits in thermoelectric materials synthesis, such as enhanced printing speed, reduced waste materials, and customized dimension design. The high energy density of laser could potentially balance the synthesis rate and thermoelectric figure-of-merit zT , but the correlations between laser energy and material performance are still vague. Herein, Bi 0.5 Sb 1.5 Te 3 bulks are directly synthesized by LPBF with a recorded synthesis rate of 254 g h−1. The maximum zT , without any post-processing, reaches 1.1 at 75 °C. Induced nanoscale pores by high laser energy printing, obtain a comparable diameter to phonon mean free path, leading to reduced lattice thermal conductivity and enhanced TE performance. We found that input laser energy critically affected thermoelectric performance and concluded the correlation between volumetric energy density E V and power factor PF , PF = 9.05 E V 2 – 30.01 E V + 48.84. It potentially predicts thermoelectric performance with inputted laser energy density. [ABSTRACT FROM AUTHOR]