Research of Organolead Halide Perovskite Electronic Devices

Abstract

In the past ten years the efficiency of organolead halide perovskite solar cells has jumped from 3 8% in 2009 to 25 2% in 2019 It has adjustable and good optoelectronic properties variable but low temperature non-vacuum process and poor water-oxygen resistance These properties make organolead halide perovskite of research value in both academic and commercial applications This thesis studies solar cells and resistive memory made by organolead halide perovskite as the main material When water and potassium halide simultaneously doped in the perovskite precursor lead iodide solution of two-step method there is no significant change in the surface of the perovskite film but the photovoltaic conversion efficiency(PCE) increased caused by open-circuit voltage(VOC) short-circuit current(ISC) and fill factor(FF) increased Through photoluminescence(PL) measurement it can be seen that doping of only potassium iodide or potassium chloride can effectively improve the non-radiative recombination defects in the film or interface From Auger electron spectroscopy(AES) depth analysis it can be seen that the potassium signal penetrates into the hole transport layer and the electron transport layer Compared with the above analysis it can be confirmed that the potassium ion improves the efficiency of the perovskite solar cell after improving the interface Potassium iodide was also doped in the perovskite resistive memory of ITO/PEDOT:PSS/MAPbI3/PMMA/Al structure Appropriate potassium iodide doping can increase cycle endurance and retention time Excessive potassium iodide doping made the film pores and damaged memory characteristics It can be seen that the potassium iodide doping mainly enhances the crystallinity of the perovskite film from consistent PL and X-ray diffraction(XRD) analysis X-ray photoelectron spectrum(XPS) depth analysis indicated that the potassium ions mainly act on the PEDOT:PSS/MAPbI3 interface and the reduction in defects makes devices difficult to be permanently opened or shorted for the path in the resistive memory In order to make less defects in the perovskite film high preferring orientation and large-grain perovskite film is a possible research direction Three-step method was applied to make perovskite film First voided lead sulfide grains were deposited by chemical bath method And then flaky lead iodide grains were formed after heating with the iodine sheet Finally after annealing with methylammonium iodide(MAI) a high preferring orientation and large-grain perovskite film was obtained Comparing with perovskite film of similar thickness made by two-step method the memory on/off ratio is slightly higher but the operating current is 103 times lower by lead sulfide method It represented lower power consumption and longer lifetime In summary this study uses doped potassium halide and high preferring orientation organolead halide perovskite film to repair defects in the film and its interface of layers making it a better application in electronic components

Date of Award	2020
Original language	English
Supervisor	Chuan-Feng Shih (Supervisor)