Quantum dot light enhancement substrate and lighting device including same
摘要
說(shuō)明書(shū)
In certain embodiments, QDs comprise cadmium-free materials. Examples include, without limitation, QDs comprising InP or InxGax-1P. In certain embodiments utilizing these materials, three to four distinctly different peak emission wavelengths can be used to simulate a white light spectrum optimized for high CRI. In certain embodiments, the QD emission spectra in combination with the sky-blue Ph-OLED spectrum exhibit a full-width-at-half-maximum (FWHM) in the range of 45-50 nm or less. In certain embodiments, a predetermined CRI is achieved with 3-4 specifically tuned QD emission spectra. In certain embodiments, core/shell QD comprise a core comprising InP or InxGax-1P. In certain embodiments, an InP/ZnSeS core-shell system can be tuned from deep red to yellow (630-570 nm), preferably with efficiencies as high as 70%. For creation of high CRI white QD-LED emitters, InP/ZnSeS QDs are used to emit in the red to yellow/green portion of the visible spectrum and InxGax-1P is used to provide yellow/green to deep green/aqua-green emission.
In certain embodiments, QD cores comprising InP or InxGax-1P will have a shell on at least a portion of the core surface, the shell comprising ZnS. Other semiconductors with a band gap similar to that of ZnS can be used. ZnS has a band gap that can lead to maximum exciton confinement in the core. As discussed above, in certain embodiments utilizing ZnS, InP, and/or InxGax-1P, a sphalerite (Zinc Blende) phase is adopted by all four semiconductors. The lattice mismatch between GaP and ZnS is less than 1%, while the lattice mismatch between InP and ZnS is about 8%, so doping of Ga into the InP will reduce this mismatch. Further, the addition of a small amount of Se to the initial shell growth may also improve shell growth, as the mismatch between InP and ZnSe is only 3%.
