Jang Junho, Yoon Da-Eun, Kang Seung-Mo, Kim Yong Ho, Lee Ilsong, Lee Hyunhwan, Kim Yun Hyeok, Lee Doh C, Bae Byeong-Soo
Wearable Platform Materials Technology Center (WMC), Department of Materials Science and Engineering, KAIST Institute for the Nanocentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
Nanoscale. 2019 Aug 8;11(31):14887-14895. doi: 10.1039/c9nr04517a.
Herein, we report a luminescent light-emitting diode (LED) encapsulating material using a thermally curable quantum dot (QD)/siloxane hybrid (TSE-QD) color converter, which has superior long-term stability even at elevated temperatures, in high humidity, and in various chemicals. The TSE-QD is cured by a thermal-induced hydrosilylation reaction of an in situ sol-gel synthesized QD dispersed siloxane resin (QD/siloxane resin) without additional ligand-exchange processes. QDs are successfully encapsulated by highly condensed and linear structured siloxane networks with additional chemical linkages between the surface ligands of the QDs and organic functional groups of the siloxane matrix. Moreover, QDs are uniformly distributed within the siloxane matrix retaining their optical properties during the fabrication processes of the TSE-QD. The result is that the stability, as evaluated by the photoluminescence (PL) quantum yield (QY), is greatly improved under harsh conditions, for example, 120 °C/5% relative humidity (RH), ethanol and acetone for 30 days. Based on the exceptionally stable TSE-QD, we demonstrate a white LED using a blue LED chip directly encapsulated by a yellow emitting TSE-QD that shows excellent spectral stability, outstanding reliability at 85 °C/85% RH and a wide color gamut (116% of NTSC).
在此，我们报道了一种使用热固化量子点（QD）/硅氧烷杂化物（TSE-QD）颜色转换器的发光二极管（LED）封装材料，该材料即使在高温、高湿度和各种化学物质环境下也具有卓越的长期稳定性。TSE-QD通过原位溶胶-凝胶合成的QD分散硅氧烷树脂（QD/硅氧烷树脂）的热诱导硅氢加成反应固化，无需额外的配体交换过程。量子点通过高度缩合和线性结构的硅氧烷网络成功封装，量子点表面配体与硅氧烷基质的有机官能团之间存在额外的化学键。此外，在TSE-QD的制备过程中，量子点均匀分布在硅氧烷基质中并保持其光学性质。结果是，通过光致发光（PL）量子产率（QY）评估，在恶劣条件下，例如120°C/5%相对湿度（RH）、乙醇和丙酮环境中30天，稳定性得到极大提高。基于这种异常稳定的TSE-QD，我们展示了一种白色LED，它使用蓝色LED芯片直接封装在发射黄色光的TSE-QD中，该白色LED显示出优异的光谱稳定性、在85°C/85%RH下的出色可靠性以及宽色域（NTSC的116%）。
