Narrow-spectrum Perovskite Light-emitting Device Controlled By Resonant Cavity

Inrecent years,emerging metal halide perovskite materials have become a research hotspot in the field of advanced displays,due to their advantages over III-V inorganic semiconductors such as GaN,InGaN,and organic materials such as BBEHP-PPV and ADS233YE.These advantages include high Photoluminescence Quantum Yield（PLQY）of 50%-100%,narrow Full-Width Half-Maximum（FWHM）of 15 nm-35 nm,easily tunable bandgap（temperature and composition）,low cost（simple and readily available raw materials）,simple preparation process（solution-based preparation）,and high carrier mobility.However,with the introduction of the BT.2020new standard for ultra-high-definition displays,the color purity of perovskite materials alone is insufficient to cover the Rec.2020 color gamut proposed by the new standard.Therefore,the perovskite light-emitting devices with narrower emission spectra are needed,with laser-based devices being the most superior.However,traditional commercial semiconductor lasers are bulky and can only be used for laser projection displays.For wider applications such as flat-panel displays,the development of on-chip integrated electrically-pumped lasers is needed.For display applications,where the demand for beam quality is not high,the device with narrowed spectrum through a resonant cavity represents a potential means to achieve ultra-high-definition displays.Therefore,this article aims to achieve the following objectives:（1）Synthesis of red,green and blue emitting perovskite quantum dots.By selecting a specific mixed halogen ratio and using a thermal injection method,we successfully synthesized and characterized red,green,and blue emitting all-inorganic perovskite quantum dots,with emission peaks at 628 nm,527 nm,and 467nm,PLQY of 80%,90%,16%,FWHM of 30 nm,18 nm,and 17 nm,respectively.The emission wavelengths of perovskite quantum dots are close to the three primary color wavelengths（630 nm,530 nm,and 467 nm）required by the Rec.2020 color gamut,which lays the foundation for subsequent device fabrication.（2）Optimization of the performance of blue perovskite quantum dots.We optimized the blue emitting Cs Pb(Cl_0.43Br_0.58)₃ quantum dots with low PLQY by using phenyl trifluoromethanesulfonate（PTFMS）,and analyzed their morphology,optoelectronic properties,and stability.We found that the morphology and crystal phase of blue Cs Pb(Cl_0.43Br_0.58)₃ quantum dots remained unchanged after PTFMS passivation,but their PLQY increased from 16%to 85%,and their spectral stability was improved,which will help improve the performance of subsequent devices.（3）Fabrication of narrow-spectrum perovskite LED based on resonant cavity.We first fabricated the Distributed Bragg Reflector（DBR）resonant cavity and narrow-spectrum devices,and performed their performances.Then,the spectral and color coordinate changes of LED devices with and without resonant cavities were compared.It can be seen that the LEDs with dual DBR resonant cavity show narrower spectrum and wider the color gamut range compared to the devices without resonant cavity,which can effectively cover the Rec.2020 color gamut.