Transparent Laminated Electrode Applied To Perovskite Optoelectronic Device

Perovskite nanomaterials have excellent physical properties due to their strong photoluminescence ability,tremendous harmonic oscillator strength,and little non-radiative recombination loss.Moreover,the perovskite material has a simple process,low production cost,and is suitable for large-area preparation.These attractive features make perovskite materials have extensive application prospects in the field of display and lighting devices.The future display device will develop in the direction of flexible,transparent and portable,so it is of considerable significance to study new electrodes suitable for perovskite optoelectronic devices.We proposed a composite electrode with a laminated structure to replace traditional conductive materials for perovskite electroluminescent devices,hoping to improve the performance of the device.In this paper,the optical and electrical properties of laminated electrodes are studied,and all-inorganic perovskite electroluminescent devices with good thermal stability are prepared by evaporation method.We have improved the performance of the device from the perspective of device design.The research content includes the following two aspects:1.First,we studied a flexible transparent electrode based on ZnO/Ag/ZnO structure.First,we briefly discussed the growth process of ZnO and then explored the optical and electrical properties of ZAZ electrodes with different silver thicknesses.We found that the thickness of silver has a substantial impact on the overall performance of the structure,and this phenomenon was analyzed combined with the growth model of the metal.After that,we determined the appropriate thickness range of the silver metal layer and obtained electrode performance close to that of ITO.It has also been found that although the transmittance of 20nm silver electrode is slightly lower,the loss of light is little.Therefore,ZAZ electrode is suitable for device structures with optical resonators.2.Second,we have prepared a CsPbBr₃ perovskite electroluminescent device with an optical resonant cavity,which consists of a semi-transmissive and semi-reflective ZAZ electrode and a fully reflective aluminum electrode.We try to improve the performance of perovskite light-emitting devices through the microcavity effect.We first characterized the CsPbBr₃ perovskite film grown by evaporation,and then successfully fitted the refractive index and extinction coefficient of CsPbBr3 with an ellipsometer.We used the measured CsPbBr₃ optical constants to design a perovskite electroluminescent device,calculating the appropriate thickness of each layer of the device structure.Combining a couple of the electric field strength and dipole,the influence of the position of the perovskite layer on the spontaneous emissivity was analyzed.Finally,we successfully fabricated the designed CsPbBr₃ light-emitting device with improved performance using the Fabry-Perot cavity system.The current efficiency was increased by 24%compared to the ITO device,and a weak couple of the dipole and the microcavity was proved by experiment.