High resistive switching current ratio, excellent endurance and stability for bistable non-volatile memristor and photosensing devices based on perovskite/titanium dioxide embedded in polyvinyl alcohol matrix

Abstract

This study demonstrates the excellent endurance and stability of a high resistive switching current ratio for bistable non-volatile memristor and photosensing of a fabricated CH₃NH₃PbBr₃-TiO₂/PVA/FTO-coated glass substrate. Structural, optical, and electrical properties of fabricated devices TiO₂/PVA/FTO-coated glass substrate (D1), CH₃NH₃PbBr₃/PVA/FTO-coated glass substrate (D2), and CH₃NH₃PbBr₃-TiO₂/PVA/FTO-coated glass substrate (D3) were examined in detail. The current-voltage (I-V) characteristic of device D3 shows the bistable non-volatile resistive switching memory having an ON/OFF current ratio of ∼10⁷ for over 5000 sweeping cycles. Device D3 exhibited a significantly higher ON/OFF current ratio compared to devices D1 and D2. Additionally, its operating voltage was substantially lower than that of the control samples D1 and D2, making it highly suitable for low-power electronic applications. Moreover, the stability and retention measurements were performed for device D3 in terms of resistance; the ON/OFF resistance ratio was found to be ∼10⁷ at a read voltage of 1V. The device D3 maintained excellent stability even after continuous operation for ∼10⁵ s, with no significant signs of degradation. Hence, the device D3 has good endurance, stability, and a high resistive switching current ratio, which is suitable for rewriteable non-volatile memristors. Furthermore, the photocurrent, photo-detectivity, and photoresponsivity of the same devices D1, D2, and D3 were studied under broadband light illumination with an intensity of 100 mW/cm². Interestingly, it has been observed that the three devices show a good response of photocurrent at different voltages. The device D3 exhibited superior performance compared to D1 and D2. The values of current density under dark and light of device D3 are found to be ∼1.98 × 10⁻⁸ A/cm² and ∼2.53 × 10⁻⁵ A/cm², respectively, with the corresponding ON/OFF current ratio as ∼1277. This is due to the combination of perovskite CH₃NH₃PbBr₃ and TiO₂ and enhanced electron-hole pair generation, resulting in increasing the concentration of the charge carrier. The responsivity and photodetectivity of devices exhibit a similar trend as photocurrent. The maximum values of responsivity and photodetectivity of device D3 have been obtained at 1V and found to be ∼2.52 × 10⁻² A/W and ∼3.15 × 10¹¹ Hz^1/2/W, respectively. Therefore, this device D3 also has the potential to be used for photosensing devices. Hence, the fabricated device D3 has excellent endurance, stability, high resistive switching current ratio, and photoresponse, which makes it an outstanding candidate for non-volatile memristor and photosensing applications.