All-Inorganic Quantum Dot Nanocomposite for On-Chip LED Application

Quantum dots (QDs) have recently attracted intensive research interest with their advantage optical properties and easy processing in micro/mini-LED applications. However, integrating QDs into LED packaging still faces critical challenges of fluorescent quenching and thermal-induced degradation. In this report, we investigated the QDs concentration related fluorescent quenching and the positive role of light scatterers in light-conversion efficiency. A QDs/SiO2-BN inorganic assembly nanocomposite (QDAs) was fabricated, which provided enhanced light scattering, high thermal conductivity, and moisture protection for QDs under illumination. Optical and thermal simulations were employed to investigate the optical and thermal behavior of the QDAs in on-chip LED package. The QDs converted LED (QCLEDs) demonstrate much lower operation temperature accompanied with largely improved efficiency and long-term stability.

1. Introduction

Recent years have witnessed the fast evolution of the display technology towards wide color gamut, high dynamics, and high-definition, which also put forward new demands for light-emitting diodes (LEDs) integration technologies and luminescent materials [1]–[2]. Among them, micro/mini-LED display technology has shown strong competitive advantages with its high brightness, ultra-fast response, wide color gamut, and low power consumption [3]–[4]. However, integrating multi-color micro/mini-LED chips in large display panel face the difficulties in mass transfers of RGB color chips, low assembly yield, high manufacturing cost, and complicated driving circuits [5]–[6]. Therefore, the use of monochromatic blue or ultraviolet micro/mini-LEDs plus multi-color luminescent light-down conversion materials has become a viable technical solution because of the economic benefit and simpler processing [7]–[8]. Colloidal quantum dots (QDs) are ideal fluorescent materials with their broad color tunability, high photoluminescence quantum yield (PLQY), and narrow-band emission to fulfill the purpose [9]–[11]. Especially, unlike conventional micro-sized phosphors, QDs possess a size of less than 100 nm and a surface that can be easily tailored with organic ligands to realize mono-dispersion in various polymer matrices for compatibility with micro/nano manufacturing process. [12]–[13] These promising characteristics make the QDs remarkable light-conversion material that meets the high demands of ultra-wide color gamut in next-generation display standards [15]–[16].