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A surface photovoltaic effect-related high-performance photodetector based on a single CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> micro/nanowire
摘要： With the decrease of materials to the nanoscale, their surface states will play a crucial role in their performance. Here, an individual CH3NH3PbI3 micro/nanowire-based photodetector can show excellent sensitivity and responsivity to light with a wide wavelength range from 200 to 850 nm. A surface state-related photovoltaic effect associated with a surface barrier can be formed due to a depletion of majority carriers (holes) in the surface space charge region. At a low operation voltage, the photodetector can exhibit a low dark current. Upon illuminating near the end connected to the positive electrode, the light-induced decrease of the surface barrier leads to enhanced conduction, showing a large photocurrent. At zero bias, additionally, the photodetector can show a relatively large photogenerated voltage and current when only the vicinity of one end is illuminated. Based on the CH3NH3PbI3 micro/nanostructure performance herein, surface photovoltaic-controlled photodetectors with superior performance will have important applications in new-generation optoelectronic devices.
关键词： CH3NH3PbI3,optoelectronic devices,photodetector,surface photovoltaic effect,micro/nanowire
更新于2025-09-23 15:19:57
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Effect of doping mechanism on photogenerated carriers behavior in Cu-doped ZnSe/ZnS/L-Cys core-shell quantum dots
摘要： Cu-doped ZnSe/ZnS/L-Cys core–shell QDs are prepared by both nucleation doping and growth doping in an aqueous synthesis method. Transport of photogenerated free charge carriers (FCCs) in these Cu-doped QDs is probed via a combination of surface photovoltaic (SPV), photoacoustic (PA), and electric-field-induced SPV techniques, supplemented by the UV–VIS absorption spectrum and Raman spectrum. The results confirm that the two doping mechanisms result in different doping locations and microelectronic structures of the Cu-doped QDs. The distinctive microelectronic structure of the QDs prepared by nucleation doping, as compared with those prepared by growth doping, results in a number of favorable SPV characteristics. For example, the QDs prepared by nucleation doping exhibit a higher SPV response intensity at 600 nm because of a higher concentration of photogenerated FCCs. The ratio of the strongest SPV response and the strongest PA signal of the QDs prepared by nucleation doping is up to 2.41 times greater than those of the QDs prepared by growth doping. This is because the greater numbers of photogenerated FCCs in the QDs prepared by nucleation doping generate the PV effect rather than the PA effect that is caused by a nonradiative de-excitation process. The position of the shoulder peak of the SPV response at a long wavelength of the QDs prepared by nucleation doping is significantly red-shifted compared with that of the QDs prepared by growth doping, leading to a broader SPV response range in the visible region. The QDs prepared by nucleation doping have a more obvious donor feature than those prepared by growth doping.
关键词： photogenerated carriers,Cu-doped ZnSe/ZnS/L-Cys,quantum dots,photoacoustic,surface photovoltaic,nucleation doping,growth doping
更新于2025-09-11 14:15:04