Efficiently Luminescent and Stable Lead-free Cs3Cu2Cl5@ Silica Nanocrystals for White Light-Emitting Diodes and Communication

The poor stability of lead-free Cs3Cu2Cl5 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 Cs3Cu2Cl5@SiOx NCs is proposed. Due to the efficient passivation and robust protection of SiOx shells on the NCs surface, Cs3Cu2Cl5@SiOx NCs solution and films exhibit a high photoluminescence quantum yield of 98% and 76%, respectively, and improved stability against water and heat. Cs3Cu2Cl5@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 Cs3Cu2Cl5@SiOx NCs with an efficient optical performance and an excellent stability might promote the development of stable NCs and extend the applications in optoelectronics.

Automated summary

The sol-gel reaction using tetraethoxysilane (TEOS) as a coating precursor for Cs3Cu2Cl5@SiOx NCs enhances their stability and photoluminescence quantum yield, leading to the fabrication of high-quality warm white light-emitting diodes. Additionally, the good white light emission enables potential applications in visible light communication.