We report a simple, robust, and inexpensive strategy to enable all-inorganic CsPbX3 perovskite nanocrystals (NCs) with a set of markedly improved stabilities, that is, water stability, compositional stability, phase stability, and phase segregation stability via impregnating them in solid organic salt matrices (i.e., metal stearate; MSt). In addition to acting as matrices, MSt also functions as the ligand bound to the surface of CsPbX3 NCs, thereby eliminating the potential damage of NCs commonly encountered during purification as in copious past work. Quite intriguingly, the resulting CsPbX3-MSt nanocomposites display an outstanding suite of stabilities. First, they retain high emission in the presence of water because of the insolubility of MSt in water, signifying their excellent water stability. Second, anion exchange between CsPbBr3-MSt and CsPbI3-MSt nanocomposites is greatly suppressed. This can be ascribed to the efficient coating of MSt, thus effectively isolating the contact between CsPbBr3 and CsPbI3 NCs, reflecting notable compositional stability. Third, remarkably, after being impregnated by MSt, the resulting CsPbI3-MSt nanocomposites sustain the cubic phase of CsPbI3 and high emission, manifesting the strikingly improved phase stability. Finally, phase segregation of CsPbBr1.5I1.5 NCs is arrested via the MSt encapsulation (i.e., no formation of the respective CsPbBr3 and CsPbI3), thus rendering pure and stable photoluminescence (i.e., demonstration of phase segregation stability). Notably, when assembled into typical white light-emitting diode architecture, CsPbBr1.5I1.5-MSt nanocomposites exhibit appealing performance, including a high color rendering index (Ra) and a low color temperature (Tc). As such, the judicious encapsulation of perovskite NCs into organic salts represents a facile and robust strategy for creating high-quality solid-state luminophores for use in optoelectronic devices.
Bibliographical noteFunding Information:
This work is supported by the Air Force Office of Scientific Research (MURI FA9550-14-1-0037; FA9550-16-1-0187), DOD-DTRA (HDTRA1-18-1-0004), DOE-STTR (DE-SC0018611) and National Natural Science Foundation of China (grant nos. U1632151 and 61076040). Y.C. gratefully acknowledges financial support from the China Scholarship Council.
This work is supported by the Air Force Office of Scientific Research (MURI FA9550-14-1-0037; FA9550-16-1-0187), DOD-DTRA (HDTRA1-18-1-0004), DOE-STTR (DESC0018611), and National Natural Science Foundation of China (grant nos. U1632151 and 61076040). Y.C. gratefully acknowledges financial support from the China Scholarship Council.
© 2018 American Chemical Society.
- CsPbX NCs
- metal stearate