【Adv.Optical Mater.】澳门科技大学唐建新、华东师范李艳青等|单组分白光OLED新思路：靠聚集诱导双延迟荧光拿到8.4%外量子效率与稳定光谱#

文章标题：Achieving White Electroluminescence from a Single‐Component Emitter by Harnessing Aggregation‐Induced Dual Delayed Fluorescence 文章作者：Hao-Ze Li, Feng-Ming Xie, Yu-Tao Yang, Yi-Cheng Zhao, Yan-Qing Li, Jian-Xin Tang 文章链接：https://doi.org/10.1002/adom.71931

Chemical structures of white emitters for SC-WOLEDs with different mechanisms including (a) excimer-based emission, (b) dual-conformation systems, and (c) excited-state intramolecular proton transfer (ESIPT). (d) Molecular design strategy for achieving white light emission through aggregation-induced dual TADF.

为什么单分子白光很难做稳#

白光OLED通常要把蓝、黄等多个发射体混在一起，但多组分容易相分离、掺杂比例难控，驱动电压一变光谱就漂。单分子白光能绕开这些问题，可它要求一个分子同时发高能和低能光，这违背了Kasha规则（通常只从最低激发态发光）。已有单分子方案（激基复合物、双构象、ESIPT）常遇到光致发光与电致发光构型不匹配、量子产率低、激子分配不均。本文要回答的是：能不能用单一TADF分子，通过聚集态下的双发射，做出光谱稳定的白光。

Geometry, HOMO, LUMO and LUMO+1, natural transition orbital (NTO) distributions (orange: hole, cyan: electron), RDG isosurface and map, singlet and triplet energy-level diagrams, and spin-orbit coupling (SOC) matrix elements between the S1/ S2 and T_n_ states for 2tCz-2tBO.

一个分子怎么同时发蓝光和黄光#

作者设计了2tCz-2tBO，给体是平面2tCz，受体是两个多重共振tBO，通过螺芴连接成近平面A-D-A构型。单晶显示给体-受体距离约3.35–3.45 Å，空间电荷转移（TSCT）占比超过98%。稀甲苯溶液中发深蓝光430 nm，ΔEST约0.20 eV，PLQY达65%；在THF/水混合体系中，水含量超过50%后出现440 nm单体与550 nm聚集体双发射，90%水时以550 nm为主。把分子掺进PMMA膜，低浓度只发蓝光，高浓度出现双发射，蓝光和黄光组分都有微秒级延迟寿命，证实两者都是TADF。器件采用真空蒸镀，优化后EQE_max为8.4%，EL峰在438和554 nm，CIE坐标**(0.311, 0.349)，接近D63白点；6–8 V下ΔCIE小于0.01**。作者把EQE低于顶级单发射体WOLED（13.0%）归因于PLQY仍不够高、主客体能量转移不完全和载流子传输不平衡；器件是蒸镀结构，原文未验证溶液加工或柔性基底。

(a) UV–vis absorption of 2tCz-2tBO in diluted toluene solution. Corresponding room-temperature fluorescence (RT FL), low-temperature fluorescence (77 K FL) and low-temperature phosphorescence (77 K Ph) spectra in 2Me-THF. (b) PL spectra of 2tCz-2tBO in various solvents. (n-H = n-hexane, Tol = toluene, THF = tetrahydrofuran, DCM = dichloromethane). (c) PL spectra of 2tCz-2tBO in THF/H2O mixtures with different water fractions (f w = 0%–90%). (d) PL spectra of 2tCz-2tBO doped in PMMA film with different doping concentrations. (e) Transient photoluminescence decay curves of 2tCz-2tBO doped in PMMA film. (f) Energy transfer diagram of 2tCz-2tBO based on dual TADF emission from monomer and aggregate.

(a) Energy-level diagram and chemical structures of the functional layer materials for the devices based on 2tCz-2tBO. (b) EQE-current density curves (inset: photograph of OLED). (c) Normalized electroluminescence spectra and (d) CIE color coordinates of OLED at different voltages (6–8 V). (e) Schematic illustration of the dual-emission mechanism in the doped film. (f) Normalized electroluminescence spectra and (g) CIE color coordinates of different doping ratios OLED.

能用到哪一步#

这项工作把高能蓝光和低能黄光解耦在同一个分子的单体和聚集态上，省掉了多发射体共混的相分离和掺杂控制，给显示和照明厂商提供了一条简化器件结构的路径。但8.4%的EQE距离商业化仍有差距，且所有数据来自实验室蒸镀器件，长期工作寿命、大面积均匀性和溶液法兼容性原文均未提供。它更像一个设计原则的验证，而不是可以直接量产的方案。