Coexistence of Contact Electrification and Dynamic p–n Junction Modulation Effects in Triboelectrification

Abstract

The triboelectric effect occurs when two dissimilar materials are in physical contact, attributed to the combination of contact electrification (CE) and electrostatic induction. It has been extensively explored for the development of high-performance triboelectric nanogenerators (TENGs). In this paper, we report on, besides the CE-related charge generation, an additional charge generation phenomenon associated with the modulation of the p–n junction when two semiconductor materials [methylammonium lead iodide (MAPI) and poly­(3,4-ethylenedioxythiophene)–poly­(styrenesulfonate) (PEDOT:PSS)] are put in contact and separated dynamically. The electrical outputs generated by the CE effect are determined by the surface potential difference between the two friction materials, while the ones induced by the p–n junction modulation are determined by the dynamic variations in the depletion widths of the two semiconductor friction materials. The outputs generated by the CE effect and the p–n junction effect are well separated in time scale; the p–n junction modulation contributes ∼20% of the total charge generated and could be varied by changing the chemical composition of the semiconductors. The results may provide an alternative method for the development of high-performance TENGs by utilizing this additional p–n junction modulation effect.

A United Triboelectrification Mechanism for Contacts between All Types of Materials

“…The charge transfer process for the P–S TENG is similar to that of the S–S TENGs discussed in previous work. [ 39 ] When the separation distance of the friction materials is larger than L MAX ( d > L MAX > 0), negative and positive charges will stably accumulate on E#1 and E#2, respectively, owing to the ESI effect, as shown in Figure 4f. When the distance gets close to d < L MAX , the negative and positive charges on the surfaces of the friction materials shield each other.…”

“…This is estimated to be about 0.1–0.2 eV according to the I–V measurements in previous study. [ 39 ] The change of barrier height due to the contact–separation with polymer is much lower, at about 10–50 meV. The depletion width is given by $$$$\begin{eqnarray}{x}_{\rm{p}} = \sqrt {\frac{{2{\varepsilon }_{\rm{r}}{\varepsilon }_0{V}_{\rm{D}}}}{{q{N}_{\rm{A}}}}} \ \end{eqnarray}$$$$where ɛ r is the relative dielectric constant, ɛ 0 is the vacuum dielectric constant, V D is the barrier height, and N A is the carrier concentration of semiconductor.…”

“…[35][36][37][38] Previous works have demonstrated that the contact electrification induced current and dynamic p-n junction modulationinduced current coexist and can be well separated in time scale when two organic semiconductor materials (methylammonium lead iodide [MAPI] and poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) [PEDOT:PSS]) were used as the friction materials. [39] Figure 1d(iii) presents a typical current output with distinct four peaks for the S-S triboelectrifications. These are different from the outputs of the only contact electrification currents for the typical P-P and P-M triboelectrifications.…”

Roadmap on energy harvesting materials

“…Varying composition ratio or percentage of metal ions of a perovskite could distinctly modify conductivity, electron affinity, piezoelectric property etc. These are anticipated to bring extra degrees of freedom to design new types of triboelectric nanogenerators and self-driven sensors, and they are very effective in altering material properties [251]. However, the lack of systematic investigation and fundamental research have inhibited its progress, and most of the research relied on the trial-and-error approach with no theoretical guidance for material and device development.…”

Highly Flexible Tribovoltaic Nanogenerator Based‐on P‐N Junction Interface: Comparative Study on Output Dependency Dominated by Photovoltaic Effect in Freestanding‐Mode

“…At the first stage of the TVNG development, various conventional semiconductors, e.g., Si, [ 8b,c,9b,11 ] GaAs, [ 9d ] and GaN, [ 9b,c ] have been employed as the main frictional layer of the TVNG. The series of halide perovskite, e.g., methylammonium lead iodide (MAPI), [ 10 ] Cs 0.175 FA 0.750 MA 0.075 Pb(I 0.880 Br 0.120 ) 3 (CsFAMA), [ 12 ] and CsPBr 3 , [ 9a ] were then selected alternatively for the TVNG. Due to excellent optoelectronic performance of perovskite, experiments have confirmed that the tribovoltaic effect can work synergistically with the photovoltaic effect.…”