Metal-free phthalocyanine (H2Pc) has been widely used as photosensitive semiconductors in the organic optoelectronics field because of its unique planar molecular structure and high photocarriers’ generation efficiency. Herein, this paper related to a new facile and efficient one-step method for preparing specific crystal form of H2Pc with high crystallinity through ball-milling process, in which α-H2Pc can be prepared directly by dry ball-milling, and β-H2Pc and X-H2Pc can be simply obtained through wet ball-milling in butanone solvent at different temperatures. X-ray diffraction (XRD) was used to characterize the crystal stability of α-H2Pc, β-H2Pc, and X-H2Pc, which revealed that all the three crystalline H2Pc prepared had excellent crystal stability under different mechanical conditions.
The stability problem of pulse-width-modulated feedback systems with time-varying delays and stochastic perturbations is studied. With the help of an improved functional construction method, we establish a new Lyapunov-Krasovskii functional and derive several stability criteria aboutpth moment exponential stability.
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