Fig. 1: Establishing the measurement method of relative triboelectric series for inorganic–organic ML materials.
a Structure of inorganic–organic composite ML materials, interfacial movement between inorganic and organic phases under mechanical actions, and the electron transfer between ML ceramics and organic films in the case of interface amplification. b Schematic diagram of the relative triboelectric series measurement system for ML. The triboelectric charge density (TECD) between inorganic ceramics and organic films was measured to evaluate the interfacial movement between inorganic phosphors and the organic matrix in composites under mechanical actions. c Schematic diagrams of a full cycle of mechanical actions. The generation and transition of charges due to the coupling effect of triboelectrification and electrostatic induction (in the open-circuit mode) are depicted in the figure by using the pair of the BPC ceramic and PMDS film as an example. d Variations in triboelectric charge (in nC) between BPC and PDMS in the pressing-releasing cycles as a typical example of TECD tests. e Changes in voltage (in V) in the pressing-releasing cycles. f TECD between inorganic phases (top) and organic phases (bottom) determined under the same mechanical action. The abbreviations of ceramics are described in the Experimental Section. Positive TECD values indicate that the inorganic phases lose electrons (i.e., the organic phases gained electrons) during friction, and negative values indicate that the inorganic phase gains electrons. MPX [M = C (Ca), S (Sr), B (Ba); X = C (Cl), B (Br)] are abbreviations for M5-x(PO4)3 X:Eux ceramics, ZnS is short for ZnS:Mn (reference phosphor) and SC stands for silicone. g Relative triboelectric series S of tested materials calculated from the results of (f) and Eq. (2). The relative triboelectric series S of PDMS was set as the zero point. The data presented in (f) are shown as the mean ± 2 SD (standard deviation).
