This study elucidates how nitrogen functionalities influence the transition and transfer of photogenerated electrons in graphene‐based materials. Graphene oxide dots (GODs) and Nitrogen‐doped GODs (NGODs) are synthesized by thermally treating graphene oxide (GO) sheets in argon and ammonia, respectively, and then ultrasonically exfoliating the sheets in nitric acid. The nitrogen functionalities of NGODs are mainly quaternary/pyridinic/pyrrolic, and the nitrogen atoms in these functionalities are planar to the GO sheets and repair the vacancy defects on the sheets. Hydrothermal treatment of NGODs in ammonia yields ammonia‐treated NGODs (A‐NGODs), with some pyridinic/pyrrolic groups being converted to amino/amide groups. The nitrogen atoms in the amino/amide groups are not planar to the GO sheets and are prone to donate their lone pair electrons to resonantly conjugate with the aromatic π electrons. The promoted conjugation facilitates the relaxation of photogenerated electrons to the triplet states and prolongs the electron lifetime. When deposited with Pt as the co‐catalyst, the samples catalyze H2 production from an aqueous triethanolamine solution under 420 nm monochromatic irradiation at quantum yields of 7.3% (GODs), 9.7% (NGODs), and 21% (A‐NGODs). The high activity of A‐NGODs demonstrates that architecting nitrogen functionalities effectively mediate charge motion in carbon‐based materials for application to photoenergy conversion.

Temporal focusing multiphoton microscopy (TFMPM) has the advantage of area excitation in an axial confinement of only a few microns; hence, it can offer fast three-dimensional (3D) multiphoton imaging. Herein, fast volumetric imaging via a developed digital micromirror device (DMD)-based TFMPM has been realized through the synchronization of an electron multiplying charge-coupled device (EMCCD) with a dynamic piezoelectric stage for axial scanning. The volumetric imaging rate can achieve 30 volumes per second according to the EMCCD frame rate of more than 400 frames per second, which allows for the 3D Brownian motion of one-micron fluorescent beads to be spatially observed. Furthermore, it is demonstrated that the dynamic HiLo structural multiphoton microscope can reject background noise by way of the fast volumetric imaging with high-speed DMD patterned illumination.

In this study, a developed temporal focusing-based femtosecond laser system provides high-throughput multiphoton-induced reduction and ablation of graphene oxide (GO) films. Integrated with a digital micromirror device to locally control the laser pulse numbers, GO-based micropatterns can be quickly achieved instantly. Furthermore, the degree of reduction and ablation can be precisely adjusted via controlling the laser wavelength, power, and pulse number. Compared to point-by-point scanning laser direct writing, this approach offers a high-throughput and multiple-function approach to accomplish a large area of micro-scale patterns on GO films. The high-throughput micropatterning of GO via the temporal focusing-based femtosecond laser system fulfills the requirement of mass production for GO-based applications in microelectronic devices.

The multiconfiguration relativistic random-phase-approximation theory is applied to autoionizing levels of the neutral zinc atom between 4s, /, and 4p3/2 ionization thresholds. There are five Rydberg series of doubly excited states that manifest themselves as autoionization resonances in the 4s photoionization cross section. Theoretical predictions for the positions and profiles of the autoionization resonances are in excellent agreement with experiment.PACS number(s): 32.80.Dz, 32.80.Fb, 32.90.+a, 33.60.Cv