A.A. Ahmed, A.T. Nomaan, M. Rashid, Z. Yamani
King Fahd University of Petroleum and Minerals (KFUPM),
Saudi Arabia
Keywords: sustainable technology, energy harvesting, photovoltaic effect, ZnO D ETL, photodiodes
Summary:
As technology shifts toward the era of artificial intelligence (AI) and the Internet of Things (IoTs), self-driven photodiodes (PDs) are at the forefront of next-generation sensors for deploying such smart technologies. High-performance PDs, with high sensitivity, broadband detectivity, and ultrafast response, hold great promises for breakthroughs in autonomous systems, machine vision, image recognition, smart sensing, and quantum computing for next-generation AI technologies. This research reports on the fabrication of an all-low-temperature processed self-driven n-i-p organic-inorganic perovskite photodiode for multi-color detection. The fabricated device consists of aluminum oxide passivated ZnO quantum-dot (QD) electron transport layer (ETL), methylammonium lead iodide (CH3NH3PbI3) absorbing layer, and Spiro-OMeTAD hole transport layer. The PD follows ITO/ZnO QD/Al2O3/CH3NH3PbI3/Spiro-OMeTAD/Ag architecture, with ITO and Ag serving as current collectors. Low-temperature ZnO QD ETL was deposited over ITO substrate from ZnO QDs solution prepared at 60 oC and dried at 100 oC, which is advantageous for roll-to-roll perovskite solar cell fabrication. Due to the defect rich nature of ZnO QDs Al2O3 passivation was carried out to supress interfacial degradation issue of perovskite related to a direct contact with ZnO. The decomposition of perovskite photo-absorbing layer coated directly over ZnO QD ETL was inhibited by passivating perovskite/ZnO interface, as evident from XRD and XPS analyses. Interestingly, the fabricated PD revealed promising photo-characteristics in terms of open-circuit voltage (VOC), short-circuit current (ISC), photo-to-dark current ratio (PDCR), and stability upon exposing to different light sources (blue, green, orange, red, and white) at different intensities in the range of 3.7-10.5 mW/cm2. It showed VOC of ~ 0.94V, ISC above 1.0 mA, and PDCR of four orders of magnitude. These findings introduce self-driven n-i-p perovskite PDs as next-generation sensors to be integrated into the emerging sustainable technologies, such AI and IoTs.