Integration of microbattery with thin-film electronics for constructing an integrated transparent microsystem based on InGaZnO

Abstract

A full integration of miniaturized transparent energy device (lithium-ion battery), electronic device (thin-film transistor) and sensing device (photodetector) to form a monolithic integrated microsystem greatly enhances the functions of transparent electronics. Here, InGaZnO is explored to prepare the above devices and microsystem due to its multifunctional properties. A transparent lithium-ion battery with InGaZnO as anode (capacity~9.8 μAh cm^-2) is proposed as the on-chip power source. Then, thin-film transistor with InGaZnO as channel (mobility~23.3 cm² V^-1 s^-1) and photodetector with InGaZnO as photosensitive layer (responsivity~0.35 A W^-1) are also prepared on the substrate for constructing an fully integrated transparent microsystem. Each device displays acceptable performance. Moreover, alternating-current signals can be successfully charged into the lithium-ion battery by using the thin-film transistor as the on-chip rectifier and also the photodetector works well by using the charged battery as the on-chip power, demonstrating collaborative capabilities of each device to achieve systematic functions.

Fig. 1. Illustration of the integrated transparent microsystem as well as each component.

a Schematic diagrams of the integrated microsystem and its components. b Equivalent circuit diagram of the integrated microsystem. c Photograph of the complete integrated microsystem. d Transmittance of each component and the integrated microsystem. The inset is the optical image of the complete integrated microsystem placed onto a logo.

Fig. 2. Electrochemical performance of the 400-nm IGZO anode films prepared at different P_O2 measured based on the coin half cells.

a–c CV curves, d–f GCD curves, g cycling curves, and h rate performance. (Open symbol − charge; solid symbol − discharge.).

Fig. 3. Characterization of the all-solid-state thin-film LIB with 80-nm IGZO as the anode.

a Cross-sectional SEM image as well as the EDX elemental mappings. GCD curves of the LIB (b) for the initial three cycles at 1 μA cm⁻² and 25 °C, c under different current densities at 25 °C, and d under different temperatures at 14 μA cm⁻². e Cycling performance of the LIB at 14 μA cm⁻² and 25 °C. f Self-discharge curve of the LIB at 25 °C. The LIBs are activated at a low current density of 1 μA cm⁻² for three cycles firstly before testing in Fig. 3c–f.

Fig. 4. Characterization of the TFT, TFTR and PD at P_O2 = 0.04 Pa.

a Transfer curve, b output characteristics, and c rectification curve of the TFT device. The inset of Fig. 4a shows areal capacitance (C_i, μF cm⁻²) and leakage (I_i, A) as a function of applied voltage for the HfLaO-based capacitor. d AC sinusoidal signals generated by a signal generator as the TFTR input. e Half-wave DC output signals of the TFTR under different-amplitude AC sinusoidal in put signals with a fixed frequency of 100 Hz. f Half-wave DC output signals of the rectifier under different-frequency AC sinusoidal input signals with a fixed amplitude of 7 V. g Dependence of photocurrent and responsivity on the 405-nm light intensity for the PD device. h Current-time curve measured under a 405-nm light intensity of 2.3 mW cm⁻² at a bias of 5 V for the PD device. i High-resolution current-time curve under a 405-nm light intensity of 2.3 mW cm⁻² at a bias of 5 V used for measuring the rise time and decay time of the PD device.

Fig. 5. Collaborative operation of each component in the integrated transparent system.

a Test setup of LIB charging process by using TFTR as the on-chip rectifier. In this case, the switch S1 is turned-on and the switch S2 is turned-off. LIB charging process under AC sinusoidal input signals with (b) different voltage amplitudes and (c) different frequencies. d Test setup of PD photoresponse by using the charged LIB as the on-chip power. In this case, the switch S1 is turned-off and the switch S2 is turned-on. e PD photoresponse under light illumination with different power densities at a fixed wavelength of 405 nm. f Evaluation of operating time for the charged LIB used in the test setup displayed in Fig. 5d.