Luminescence Modulation And Applications Of Rare Earth Doped All-inorganic Halide Perovskite Nanomaterials

All inorganic halide perovskite has controllable electronic configuration,unique crystal structure and diverse chemical composition,showing excellent optoelectronic properties,such as high photoluminescent quantum yield(PLQY)and color purity,narrow full width at half maximum(FWHM),and long carrier diffusion length.Among them,all-inorganic lead halide perovskite quantum dots(Cs Pb X3 PQDs)have been used in photodiodes(LEDs),photovoltaic(PV)devices,photodetectors(PDs),due to their unique optoelectronic properties.In recent years,despite the research of Cs Pb X3 PQDs has made great progress,there are still some problems to be solved.First of all,the blue-violet light PLQY of Cs Pb Cl3 PQDs is low,which hinders its application in optoelectronic devices;Secondly,the stability of Cs Pb X3 PQDs is poor,especially for Cs Pb I3 PQDs,which is easy to phase decompose under oxygen and water;In addition,the application of lead-based PQDs is limited,due to the presence of toxic lead ions.In order to improve the optoelectronic properties of lead-based perovskite,the strategy of ions doping was proposed.Rare earth ions have unique4f-4f level transition,wide luminescence wavelength range,long fluorescence lifetime and high luminescence stability.However,rare earth ions also suffer from small absorption cross-sections.Therefore,based on their unique properties,rare earth ions can be doped into Cs Pb X3 PQDs and lead-free perovskite for luminescence modulation,improving the optoelectronic performance.The specific work content is summarized as follows:(1)We successfully fabricated Cr3+ doped Cs Pb Cl3 PQDs for the first time by the hot-injection method,making the blue-violet light PLQY to 82%.On this basis,Cr3+,Ce3+ and Yb3+ doped into Cs Pb Cl3 PQDs lattice.Through the lattice modification of Cr3+,Ce3+ can absorb 4f-5d in the ultraviolet(UV)region and then transfer energy to Yb3+,enabling efficient quantum cutting emission in the NIR region with PLQY up to188%,which is the highest efficiency reported in PQDs materials.In the Si PDs integrating with Cr3+,Ce3+,Yb3+ tri-doped Cs Pb Cl3 PQDs,the UV performance of Si PDs is largely boosted,displaying wide detection range(200 nm-1100 nm),and outstanding UV detection performance.(2)We successfully fabricated Er3+ doped Cs Pb I3 PQDs by modified hot-injection method.According to experimental and theoretical results reveal that optoelectronic properties and stability of Cs Pb I3 PQDs are significantly improved through Er3+ doping.Due to the narrow band gap(1.81 e V)and excellent optoelectronic performance of Cs Pb I3: Er3+ PQDs,becoming a candidate for the broadband PDs(400 nm-700 nm).To further broaden the response range of PDs,the NIR(700 nm-1000 nm)light-absorbing of organic heterojunction(BHJ,BTP-4Cl:PBDB-TF)and the efficient UV(200 nm-400 nm)absorption and visible(500 nm-700 nm)emission Cs Pb Cl3: Cr3+,Ce3+,Mn2+ PQDs luminescent concentrators(LC)were introduced,respectively.Based on the above composite films,the DUV-NIR broadband PDs prepared with the response range of 200 nm-1000 nm,and the detectivity(D*)is two orders of magnitude for Si PDs.(3)In order to modulation the optoelectronic performance of PQDs,Cs Pb F3:Yb3+,Er3+ / Tm3+ PQDs up-conversion luminescent materials were prepared by thermal injection method,and Zn2+ was introduced to control its band structure and reduce the density of defect states,further improving the optoelectronic properties of PQDs.In addition,the vertical gold nanorod(Au NRs)array with plasma resonance effect(LSPR)is introduced into Cs Pb F3:Zn2+,Yb3+,Er3+ / Tm3+ PQDs film layer to further improve local field strength and photoelectric response performance.Finally,narrowband NIR PDs was prepared based on vertical Au NRs array and Cs Pb F3: Zn2+,Yb3+,Er3+ / Tm3+ PQDs composite film,and its D* value exceeds 1012 Jones.Detailed experiments imply that its mechanism originates from the direct photon-electric upconversion process,in which the NIR light initially is absorbed by Yb3+,followed by the excitation of the 4f electrons of Tm3+ or(Er3+)via energy transfer upconversion,and further the excited 4f electrons are ionized to the conduction band of PQDs.In this work,a direct photon-electric conversion process is proposed to avoid the energy loss in the up-conversion emission process.(4)Cs2Ag Bi Br6: Na+,Ce3+ was successfully prepared by anti-solution method,improving the stability and optoelectronic properties.Meanwhile,the charge extraction and transport of Cs2 Ag Bi Br6: Na+,Ce3+ LHPs films are obviously improved after integrating with Ag NPs film.By the synergistic effects of doping with Na+ / Ce3+ and coupling with the Ag NPs film,the UV-blue light wavelength PDs based on Cs2 Ag Bi Br6: Na+,Ce3+ / Ag NPs exhibit excellent performance with low dark current and high detectivity.Furthermore,the air-and UV-stability of PDs are also significantly boosted.