Study On The Effect Of Er And Mn Co-doping On The Photovoltaic Effect Of BFO

As a single-phase ferroelectric material,barium ferrite?BFO?can simultaneously have ferroelectricity and ferromagnetism at room temperature,and the open circuit voltage is not limited by the forbidden band width,which provides a breakthrough point for the upper limit of solar cell conversion efficiency.Utilizing the regulation of photovoltaic performance,many devices with specific functions have been developed,which are widely used in optoelectronic information sensing,optoelectronic information storage and microelectronic devices,and have great potential in the application of photovoltaic industry.In this thesis,BFO film was prepared by sol-gel method,and Er element and Mn element were selected for doping to improve the photovoltaic performance of BFO film.The main research contents of the thesis are as follows:1.The precursors with a concentration of 0.3mol/L were prepared by sol-gel method.The BFO films were prepared on the FTO substrate.The effects of thickness and annealing conditions on the photovoltaic performance of the samples were investigated.The results show that the six-layer BFO film annealed at 550 °C for 15 min has the best photovoltaic performance and good crystallinity.The SEM results show that the film thickness is about 530 nm.2.An Er-doped thin film sample device was prepared.The results show that Er element doping can promote phase transition,refine grains and reduce lattice spacing.The sample with 12.5% Er doping has the best photovoltaic performance,the short-circuit current density reaches 3.658 m A/cm2,the open circuit voltage is 0.45 V,the optical band gap is reduced to 2.55 e V,and the conversion efficiency is increased by 26.91 times,showing good light sensitivity and Device stability.3.A Mn doped film sample device was prepared.The experimental results show that Mn element affects the crystallization process of BFO,which increases the crystal grains,increases the defects,and increases the lattice spacing.The absorption light spectrum shows that the optical band gap of BFMO and BFO is close,and the decrease of photovoltaic performance may be related to the increase of oxygen vacancy defects.4.The Bi_0.875Er_0.125Fe_0.975Mn_0.025O₃ thin film device was prepared.The results show that the photovoltaic performance is improved compared with the Mn doped sample.Further analysis and characterization showed that the surface defects of the sample decreased,the crystallinity increased,and the optical band gap decreased to 2.52 e V,which greatly reduced the optical band gap of BFO,which provided a new idea for subsequent research.