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White quantum dot light-emitting devices (WQLEDs) are promising candidates for high-brightness, high-efficiency, and color-saturated displays. However, it is still challenging to integrate various quantum dot (QD) emitters into one device and overcome their low blue luminous efficiencies. In this paper, we report the design and fabrication of all-solution-processed WQLEDs using a trichromatic hybrid with red, green, and blue (RGB)-emitting colloidal QDs and a blue-emitting homopolymer (poly[9,9-dioctylfluorenyl-2,7-diyl]-end capped with N,N-Bis(4-methylphenyl)-aniline, ADS329BE) in the device emission region. The white emission results from the integration of the RGB emission from the QDs and the blue emission generated by ADS329BE. The obtained results indicate that the hybrid WQLEDs exhibit pure white emission with an optimized concentration and charge balance in the emission layer (EML) and the occurrence of fluorescent resonance energy transfer between ADS329BE and the RGB QDs. The proposed devices show excellent performance with a maximum luminance of 15,950 cd/m2, a current efficiency at maximum luminance of 1.43 cd/A, and a low turn-on voltage of ≤2.0 V, with Commission Internationale de l'Enclairage coordinates of (0.33, 0.34). These results indicate that the proposed method is an alternative and effective approach to achieve high performance in WQLEDs as well as other optoelectronic devices. Refereed/Peer-reviewed

We demonstrate the first-ever surface modification of green CdSe/ZnS quantum dots (QDs) using bromide anions (Br-) in cetyl trimethylammonium bromide (CTAB). The Br- ions reduced the interparticle spacing between the QDs and induced an effective charge balance in QD light-emitting devices (QLEDs). The fabricated QLEDs exhibited efficient charge injection because of the reduced emission quenching effect and their enhanced thin film morphology. As a result, they exhibited a maximum luminance of 71,000 cd/m2 and an external current efficiency of 6.4 cd/A, both significantly better than those of their counterparts with oleic acid surface ligands. In addition, the lifetime of the Br- treated QD based QLEDs is significantly improved due to ionic passivation at the QDs surface.