A new approach to stabilize the CsPbX3 quantum dots by double chemical coupling with stress

Abstract

The instability of CsPbX3 QDs has been a natural barrier to their applications. We found a new approach to stabilize the CsPbX3 quantum dots by double chemical coupling, using both (3-aminopropyl) triethoxysilane (APTES) and ethylene cellulose (EC) through forming Si-O-Si coating during hydrolysis reactions. By this way, similar spherical perovskite CsPbX3 QDs wrapped by Si-O-Si linkage with stress were achieved. Formation process, characters and optoelectronic stable properties of QDs/silica/EC composites were investigated. Highly stable QDs/silica/EC composite solid-state film was obtained with excellent water resistance of more than 3000 min. The quantum yield of green and red composites still keeps in higher level with 85% and 71% respectively, and their narrow full width at half maximum were 20 nm and 32 nm respectively. White LED (WLED) showed a highly stable working performance and excellent optical performance. CIE color coordinates was (0.3379, 0.3338) under the driving current at 80 mA. Three discrete emission peaks located at 458, 525, and 622 nm. Moreover, the luminous efficiency of WLED achieved 51.51 lm/W. Continues stable working time achieved more than 180 min under 15 mA in the air environment. More interestingly, luminous slight efficiency drop and color-rendering index rise would be recoverable after cooling.