Tozawa Makoto, Ofuji Shuto, Tanaka Mizuki, Akiyoshi Kazutaka, Kameyama Tatsuya, Yamamoto Takahisa, Motomura Genichi, Fujisaki Yoshihide, Uematsu Taro, Kuwabata Susumu, Torimoto Tsukasa
Department of Materials Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
ACS Appl Mater Interfaces. 2024 Dec 11;16(49):68169-68180. doi: 10.1021/acsami.4c13987. Epub 2024 Nov 25.
Luminescence color tuning of less toxic I-III-VI-based quantum dots (QDs) has been intensively investigated for application in wide-color-gamut displays. However, the emission peaks of these multinary QDs are relatively broad in the blue-light region compared to those in the green and red regions. Here, we report the synthesis of AgGaS (AGS) QDs that show a narrow blue emission peak through nonstoichiometry control and surface defect engineering. While as-prepared AGS QDs with angular shapes primarily exhibited a weak green photoluminescence (PL) peak at 520 nm assigned to defect-site emission, treatment with chloride ions resulted in the appearance of a sharp band-edge PL peak at 442 nm, with the number of surface defect sites decreasing as a result of rounding off the angles of the QD shape. Further coating of the QDs with a gallium sulfide (GaS) shell selectively enhanced the band-edge PL peak at 446 nm with a narrow full width at half-maximum of 22 nm, where the defect-site emission was almost eliminated due to the removal of surface defect sites. The PL quantum yield (QY) significantly increased from 5.5% for chloride-treated AGS QDs to 12% for AGS core-GaS shell QDs (AGS@GaS). QD light-emitting diodes fabricated with AGS@GaS QDs exhibited a sharp emission peak at 450 nm, slightly red-shifted from that of the PL spectrum of the QD films, accompanied by the reappearance of a weak broad defect-site emission peak at around 560 nm.
毒性较低的基于I-III-VI族的量子点（QDs）的发光颜色调谐已被深入研究，用于广色域显示器。然而，与绿色和红色区域相比，这些多元量子点在蓝光区域的发射峰相对较宽。在此，我们报告了通过非化学计量控制和表面缺陷工程合成的AgGaS（AGS）量子点，其显示出窄的蓝光发射峰。虽然制备的角形AGS量子点主要在520nm处表现出弱的绿色光致发光（PL）峰，归因于缺陷位点发射，但用氯离子处理导致在442nm处出现尖锐的带边PL峰，由于量子点形状的角度变圆，表面缺陷位点的数量减少。用硫化镓（GaS）壳进一步包覆量子点，选择性地增强了446nm处的带边PL峰，半高宽窄至22nm，由于表面缺陷位点的去除，缺陷位点发射几乎消除。光致发光量子产率（QY）从氯化处理的AGS量子点的5.5%显著提高到AGS核-GaS壳量子点（AGS@GaS）的12%。用AGS@GaS量子点制备的量子点发光二极管在450nm处表现出尖锐的发射峰，相对于量子点薄膜的PL光谱略有红移，同时在560nm左右再次出现弱的宽缺陷位点发射峰。
