The Research On Novel Heterostructure Based Light-emitting Devices And Generators

Based on the heterostructure,optoelectric and energy conversion devices such as lasers,light-emitting diodes,photodetectors,solar cells and generators can be realized.Due to the excellent electrical and optical properties of graphene and perovskite,using them in heterostructures can enrich the physical mechanism of the heterostructure and combine structure characteristics and material advantages.The junction region of the graphene/semiconductor heterojunction locates on the surface,and the performances of the device can be effectively improved through electrical and chemical control methods.The heterostructure formed by combining perovskite and energy-level matched materials can achieve selective transport of electrons and holes,thereby improving the efficiency of carrier transport.Therefore,based on the heterostructure of graphene or perovskite,through appropriate control methods,light-emitting devices and generators with high performances and new physical mechanisms can be constructed.In this paper,through the surface plasmon resonance effect and gate effect,the luminescence of graphene/Ga N heterostructure based light-emitting diodes is improved;through nonlinear photo-enhanced effect of rebound carriers and photo-generated carriers,the dynamic metal/perovskite Schottky junction based direct-current generator co-harvesting mechanical energy and light energy is realized,and its application as flexible devices is explored.The main contents of this paper are as follows:?1?Ag nanoparticles with a diameter of about 100 nm were spin-coated on the surface of graphene/P-Ga N light-emitting diode.Under the work current of 2.5 m A,the luminous intensity of the Ag nanoparticles/graphene/P-Ga N light-emitting diode was twice that of graphene/P-Ga N light-emitting diode.The enhancement effect originated from the surface plasmon resonance effect of Ag nanoparticles,which could improve the radiation recombination process of carriers and enhanced the luminous intensity of the light-emitting diode.?2?Based on the introduction of Ag nanoparticles,the graphene/PMMA/graphene sandwiched structure was designed.When the gate voltage was applied on the top-layer graphene,through the carrier injection process between the top-layer graphene and the bottom-layer graphene,the Fermi level of the bottom-layer graphene was changed and the luminous intensity of graphene/Ag nanoparticles-PMMA/graphene/P-Ga N light-emitting diode was adjusted.When the gate voltage changed from 0 V to-10 V,the luminous intensity of the light-emitting diode was 4 times the original.?3?The MA_0.5FA_0.5Pb_0.5Sn_0.5I₃ perovskite film prepared by the low-temperature spin-coating process was contacted and moved relatively with the metal,forming the dynamic metal/perovskite Schottky based direct-current generator,which could convert mechanical energy to direct-current electric energy.In the dark environment,the output voltage and current density of the the dynamic Al/perovskite Schottky based direct-current generator were-0.70 V and-41.1 A/m²,respectively.?4?Due to excellent optical properties of perovskite,such as wide spectral absorption range and high light absorption coefficient,a large number of photo-generated carriers could be produced in perovskite under illumination.Under the built-in electric field of dynamic metal/perovskite Schottky based direct-current generator,the photo-generated carriers could interact with the rebound carriers to promote the separation and acceleration of the photo-generated carriers,resulting in a nonlinear photo-enhanced effect.Through this effect,mechanical energy and light energy could be collected synergistically and the output current of the dynamic metal/perovskite Schottky based direct-current generator could be enhanced.In the dark environment,the output current of the dynamic Al/perovskite Schottky based direct-current generator was-0.55?A,while the output current was-1.80?A under AM1.5G illumination,showing a three-fold enhancement.?5?A dynamic Al film/perovskite flexible generator was prepared on the ITO/PET flexible substrate,which could produce an output voltage of-0.37 V without bending.When the benting angles were 60°and 120°,the dynamic Al film/perovskite flexible generator could still maintain 87%and 70%of the original output voltage,indicating good flexibility of the device.