Study On The Regulation And Mechanism Of Organic Encapsulation On The Luminescence Behavior Of CsPbX₃ Perovskite Quantum Dots

In recent years,perovskite materials have become the focus of photovoltaic and optoelectronic research because of their excellent photoelectric properties.Solar cells based on organic-inorganic hybrid perovskite materials have developed rapidly,and the energy conversion efficiency has reached 23.7%.The inorganic cesium lead perovskite halide is formed by replacing the organic group with the inorganic Cs⁺cation.The external quantum efficiency of led devices based on CsPbX₃nanocrystals?NCs?is up to 20%.However,the instability of perovskite materials,especially the instability of heat and humidity,brings great trouble to the design and application of optical devices.In order to improve the stability of CsPbX₃ NCs and its applications in light emitting devices,different polymers are developed to wrap the CsPbX₃ NCs.However,there is still a lack of in-depth understanding of the influence of polymer encapsulation on the luminescence and electron transition of CsPbX₃ NCs.This work explores this issue by incorporating CsPbX₃ NCs with bright emission and broad color gamut into OSTE.And absorption spectra,photoluminescence?PL?,and time-resolved photoluminescence are compared before and after OSTE packaging.In this paper,it is found that the absorption band edge of CsPbX₃ NCs in hexane corresponds to the position of emission peak,while the optical absorption band edge of different CsPbX₃ NCs after OSTE packaging is independent of the luminous color.In addition,the bandwidth of PL peak increases significantly after OSTE packaging,while the position of PL peak shifts blue.Further spectral analysis shows that OSTE encapsulation can weaken the dielectric and the binding energy of excitons decreases and the spectrum moves towards short wave.FWHM inhomogeneous broadening is due to the dipole-dipole interaction between the CsPbX₃ NCs and OSTE bases.There is a transfer of energy between CsPbX₃ NCs and OSTE.The emergence of new lifetime parameters in TRPL of CsPbX₃ NCs-OSTE further validates the energy transfer model.This work systematically studies the regulation of CsPbX₃luminescence behavior by OSTE encapsulation,and further explains the effect of OSTE encapsulation on electron transition.