Sr570 low noise current preamplifier

All I–V and current–time curves measurements are carried out with a home‐build system at room temperature which consisted of the optical and electrical parts. The optical part includes SC‐pro and AOTF‐PRO produced by OYSL and can produce 430–1450 nm light which provide the illumination needed by photodetectors. The electrical part consists of probe and Keithley 2600B and can detect the photodetectors’ current. The noise current was tested by SR830 lock‐in amplifier (Stanford research systems) and SR570 low‐noise current preamplifier (Stanford research systems). The response time was extracted from oscilloscope. The frequency spectra were tested by oscilloscope with signal‐amplifier and the LED light source adjusted by signal generator.

The EQE, responsivity, specific detectivity, noise current frequency spectra, and current–voltage (J–V) curves were recorded using an Enlitech PD‐QE system calibrated with standard Si and Ge photodetectors. LDR was measured under the illumination of a 660 nm‐LED light source equipped with neutral‐density filters, using a Keithley 2400 source meter. A network analyzer (Keysight N5227A) was used to measure the modulation bandwidth of the OPDs. The noise current was tested by an SR830 lock‐in amplifier (Stanford research systems) and an SR570 low‐noise current preamplifier (Stanford research systems). An analog front‐end evaluation board from Texas Instrument (AFE4490EVM) and its GUI software were used to process the acquired PPG signals and power the dual LEDs (660/940 nm, TE Connectivity).

We purchased the PVDF with 0.1 mm of thickness from Fils co., LTD, the PI films with 0.25 mm of thickness from EDS system Inc., and PTFE film with 0.1 mm of thickness from EDS systems. The Au electrode with100 nm of thickness was deposited by on-axis mode with deposition rate of 0.2 nm/s, 5 × 10 − 6 Torr of the working pressure, 4.3 kV of the applying power, and 16.4 mA of current, whereas Al electrode with 200 nm of thickness was deposited on PTFE at room temperature for 5 min by DC sputter with 200 W of deposition power, 1 m Torr of working pressure, and 15 sccm of Ar flow rate. The total size of the hybrid generator was 7 × 3 cm². The measurement of the output voltage and current was performed using the DPO 4014B Oscilloscope (Tecktronix) and SR570 low-noise current preamplifier (Stanford Research Systems), respectively. To measure open-circuit voltage and short-circuit current of the piezo/triboelectric hybrid generator, we have used the load resistance of 1 MΩ and 1Ω, respectively. Supplementary Fig. S10 shows the measurement configuration with those instruments. The pressing force measurement was conducted using a digital force gauge (IMADA Inc.).