Efficiently Luminescent and Stable Lead‐free Cs3Cu2Cl5@Silica Nanocrystals for White Light‐Emitting Diodes and Communication. Issue 13 (23rd April 2021) - Zhao, Shuangyi
Abstract: The poor stability of lead‐free Cs3 Cu2 Cl5 nanocrystals (NCs) is the main impediment for their broad practical applications. Here, a sol‐gel reaction using tetraethoxysilane (TEOS) as the silica coating precursor to prepare Cs3 Cu2 Cl5 @SiOx NCs is proposed. Due to the efficient passivation and robust protection of SiOx shells on the NCs surface, Cs3 Cu2 Cl5 @SiOx NCs solution and films exhibit a high photoluminescence quantum yield of 98% and 76%, respectively, and improved stability against water and heat. Cs3 Cu2 Cl5 @SiOx NCs are then used to fabricate warm white light‐emitting diodes (WLEDs), which show a high color‐rendering index of 94 and a proper correlated color temperature of 5049 K, and maintain an excellent thermal (265–360 K) and prolonged operating (380 h) stability. In addition, the good white light emission facilitates the application in visible light communication (VLC). The VLC light source demonstrates a −3 dB bandwidth of 420 kHz, and the achieved data rate of the VLC system reaches 2.65 Mbps using orthogonal frequency division multiplexing modulation with a bit loading. As a result, lead‐free Cs3 Cu2 Cl5 @SiOx NCs with an efficient optical performance and an excellent stability might promote the development of stable NCs and extend the applications in optoelectronics. Abstract : A facile SiOx coating strategy is reported to prepare green‐emitting Cs3 Cu2 Cl5 @SiOx nanocrystals (NCs) at a low temperature, in which the tetraethoxysilane (TEOS) is chosen as the silane precursor for the formation of SiOx shells. The Cs3 Cu2 Cl5 @SiOx NCs exhibit an enhanced optical performance and improved stability against heat and water, facilitating the applications of warm white light‐emitting diodes and visible light communication.