Rare Earth Luminescence Materials In The Application Of Perovskite Solar Cells

Rare earth luminescent materials have unique electronic structure that showed dramaticluminescent effect,which can implement various spectral emission through the mixed of different rare earth element theoretically.Meanwhile,rare earth luminescent material has large absorption cross section,high luminous efficiency,long decay time,stable photophysic output and strong spectral adjustment,which be widely used in biology,imaging,medical,solar cells and other fields.The perovskite solar cells as a kind of clean and low-consumed environment friendly energy bewidely attended.As a new generation leader of solar cells,perovskite solar cells（PSCs）have been highly regarded for its adjustable direct semiconductor bandgap,longer carrier lifetime,excellent conductivity and efficient photovoltaic conversion performance.In the last few years,the PSCs photovoltaic conversion efficiency（PCE）make a breakthrough that jumped from 3.8%to 22.1%as a new super star.Meanwhile,the mesoporous TiO₂ has semiconductor and skeleton as a leader that break many record in many structure of PSC.However,we discovered that MAPbI₃ perovskite can only efficiently utilize spectrum between400nm to 800nm,while as much as 44%near-infrared light would be wasted because of the energy bandgap mistake.Furthermore,the hetero-interface connect TiO₂ with perovskite be decomposed easily under UV light by reason of high efficient catalytic performance of TiO₂.Therefore,we carried out the following work:First section:We synthesized uniform size,monodisperse NaYF₄:Yb³⁺,Tm³⁺@TiO₂ nanoparticlesin solvothermal,which possess excellent upconversion luminescence,upconversion luminescence and semiconductor performance.Next,we mixed the core-shell upconversion luminescence particles with TiO₂paste for spin-coating mesoporous layer.After assemble PSCs,we find the significant enhancement in the performance of the PSCs is attributed to light scattering,NIR light upconversion and electron injection from the UCNPs to the conduction bandgap of TiO₂,which achieve about 18.77%PCE higher than the reference.The mechanism of enhancement of efficiency have been proved by UV-Vis-NIR spectrum,near-infrared upconversion luminescence spectrum and scatter spectrum.And the NaYF₄:Yb³⁺,Tm³⁺@TiO₂mesoporous layer performance get an obvious elevation compared with pure TiO₂.Second section:During to the distinct decomposition of UV light for MAPbI₃,we design theNaGdF₄:Eu³⁺as a new type luminous mesoporous film.The luminous mesoporous film not only possess high-efficient luminescence but also can’t take decomposition for perovskite layer.Firstly,we synthesized high down-conversion luminous efficiency monodisperse nanoparticles in solvothermal,and we prepare paste use the NaGdF₄:Eu³⁺nanoparticles whose surface oil molecule be stripped by hydrochloric acid in the procession of protonation.Scan electron microscope shown that the luminous mesoporous film have obvious mesoporous structure.In the meantime,we test the absorption spectrum,excitation spectrum and emission spectrum of the luminous mesoporous film,which possess high efficient down conversion luminescence and rarely absorb the visible light.Finally,we optimize the electrical performance of the luminous mesoporous layer,which would obtain high PCE and long-term stability under UV.