Flower-like In2O3/ZnO heterostructure with accelerated multi-orientation electron transport mechanism for superior triethylamine detection

Triethylamine Gas Sensors Based on BiOBr Microflowers Decorated with ZnO Nanocrystals

“…In addition, the energy spectrum of Zn is shown in Figure e. The peaks at 1044.77 and 1021.78 eV correspond to Zn 2p 1/2 and Zn 2p 3/2 , respectively, indicating the existence of the Zn 2+ oxidation state in BiOBr/ZnO composites . From the energy spectrum of O 1s in Figure f, the characteristic peaks at 532.07 and 530.37 eV binding energies can be obtained by Gaussian fitting, corresponding to the lattice oxygen (Zn–O) and oxygen vacancy (V O ), respectively.…”

“…The gas sensing mechanism of semiconductors mainly depends on a series of chemical and physical reactions of gas molecules on nanostructure surfaces. The excellent TEA sensing performances of the BiOBr/ZnO sensor can be explained by the space charge depletion layer theory. , As shown in Figure a, when the BiOBr/ZnO sensor is exposed to air, oxygen molecules will capture electrons and form oxygen anions (O – , O 2– , and O 2 – ). Among them, the dominant oxygen species at T opt.…”

“…Second, the enhanced carrier migration caused by the heterogeneous nanostructure contributes to the sensitive properties of BiOBr/ZnO composites. Abundant heterojunctions can effectively improve the interfacial electron transport and enhance the gas sensitivity . For n–n heterojunctions, electrons act as carriers for the transfer from the conduction band (CB) of n-type semiconductors with a high Fermi level to the CB of another n-type semiconductor with a relatively low Fermi level.…”

“…The work functions of ZnO and BiOBr are 5.2 and 5.91 eV, respectively, and the Fermi level of ZnO is higher than that of BiOBr, which may lead to the migration of charge carriers at the interface of the composites. , When ZnO NCs are in contact with BiOBr, electrons may transfer from ZnO to BiOBr, as shown in Figure b. Then, an internal electric field emerges at the interface of BiOBr and ZnO, ZnO loses electrons, and the energy band is bent upward, while the band of BiOBr is bent downward until the Fermi level reaches a new equilibrium. , Therefore, an EDL will form in the ZnO layer, while an electron accumulation zone may form in BiOBr. Moreover, a large number of oxygen species are adsorbed at the interface of n–n heterojunctions. , In addition, when the BiOBr/ZnO sensor is exposed to TEA, TEA will react with oxygen anions and release electrons, which narrows the EDL and reduces the resistance value.…”

Ambient Stable CsPbBr3/ZnO Nanostructures for Ethanolamine Sensing

“…The work function of ZnO (5.2 eV) is lower than that of CsPbBr 3 (5.79 eV). , After the n–n heterojunction is formed, electrons transfer from ZnO to CsPbBr 3 . As portrayed in Figure d, an internal electric field forms at the interface of CsPbBr 3 -2MPA and ZnO NPs, and the energy bands of both materials are bent until a new equilibrium is reached. , Therefore, the surface of CsPbBr 3 is the electron-rich region. The CsPbBr 3 -2MPA/ZnO heterostructures provide more abundant electrons and active adsorption sites for oxygen species, which is conducive to the formation of chemisorbed oxygen anions on the surface of heterogeneous semiconductor CsPbBr 3 -2MPA/ZnO, thus significantly improving the gas-sensitive characteristics.…”