12 Jun 15:02
by Jiance Jin, Yinghui Peng, Yuting Xu, Kai Han, Anran Zhang, Xiao-Bao Yang, and Zhiguo Xia
Chemistry of Materials
DOI: 10.1021/acs.chemmater.2c01254
12 Jun 15:01
by Zhengshuo Wang,
Anze Li,
Zihao Zhao,
Tianwen Zhu,
Qiang Zhang,
Yongzhi Zhang,
Yeqiang Tan,
Wang Zhang Yuan
Smart luminescent materials with tunable multicolor afterglows in response to excitation and delay time can be facilely constructed with aqueous processable polymers through physical doping. The afterglow colors can further be finely modulated by the variation of the doping concentration, co-doping, and the triplet-to-singlet Förster resonance energy-transfer process.
Abstract
Smart afterglow materials in response to excitation and delay time, including crystals, polymeric films, and carbon dots, have attracted considerable attention on account of their fundamental value in photophysics and promising applications in optoelectronics. However, the fabrication of amorphous and flexible polymer films with fine control remains underexplored. Herein, new doped polymer films based on sodium alginate and aromatic carboxylates are developed, which demonstrate following advantages: (i) easy and fast fabrication through the aqueous solution process, (ii) flexible, transparent, and re-dissolvable characteristics, (iii) multi-tunable afterglow colors from blue to red and even white with fine control. Specifically, even better controllability can be achieved through co-doping and triplet-to-singlet Förster resonance energy transfer (TS-FRET). Multimode advanced anti-counterfeiting of these materials is demonstrated using their excitation- and time-dependent as well as TS-FRET-mediated afterglow colors.
11 Jun 17:04
by Gui-Ping Yang, Xiao-Lin Meng, Sai-Jin Xiao, Qiong-Qing Zheng, Quan-Gen Tan, Ru-Ping Liang, Li Zhang, Pu Zhang, and Jian-Ding Qiu
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.2c05953
10 Jun 13:52
by Shichen Yin, Carr Hoi Yi Ho, Shuo Ding, Xiangyu Fu, Liping Zhu, Julian Gullett, Chen Dong, and Franky So
Chemistry of Materials
DOI: 10.1021/acs.chemmater.2c00293
10 Jun 13:49
by Dianming Sun,
Eimantas Duda,
Xiaochun Fan,
Rishabh Saxena,
Ming Zhang,
Sergey Bagnich,
Xiaohong Zhang,
Anna Köhler,
Eli Zysman‐Colman
Dendrimer Emitters
In article number 2110344, Dianming Sun, Xiaohong Zhang, Anna Köhler, Eli Zysman-Colman, and co-workers report the rational design of thermally activated delayed fluorescence (TADF) dendrimer emitters that show remarkable photophysical properties, resolving the conflicting requirements of achieving simultaneously a small activation energy and a large oscillator strength. Their use in a host-free solution-processed organic light-emitting diode (OLED), which shows record-high external quantum efficiencies, is demonstrated. The dendrimer design strategy provides a route to high-performance solution-processed TADF OLEDs and evidences the full potential of dendrimers as emissive materials.
10 Jun 13:48
by Wentao Xie,
Xiaomeng Peng,
Mengke Li,
Weidong Qiu,
Wei Li,
Qing Gu,
Yihang Jiao,
Zijian Chen,
Yiyang Gan,
Kun kun Liu,
Shi‐Jian Su
The triplet energy loss of Dexter energy transfer for red hyperfluorescence device was blocked through one-step substitution of thermally activated delayed fluorescence sensitizer by electronically inert phenyl-fluorene terminal, giving a proof-of-concept device with a maximum external quantum efficiency of 18.1% and Commission Internationale de L'Eclairage coordinates of (0.61, 0.38).
Abstract
Generally, the charge transfer character of thermally activated delayed fluorescence (TADF) materials results in a long excitonic lifetime and broad-band emission. With the combination of unity exciton utilization of TADF material and high radiative rate and narrow-band emission of conventional fluorescence (CF) dopant, hyperfluorescence organic light-emitting diodes (HF-OLEDs) attract extensive attention in industry and academia recently. Till now, Dexter energy transfer (DET) from the triplet state of TADF assistant host to the dark triplet state of CF guest is the top-drawer energy loss issue root in HF-OLEDs. Herein, the energy loss of DET is blocked through one-step substitution of TADF assistant host by electronically inert phenyl-fluorene terminal for the first time. The blocking effect on DET process in HF-OLEDs is investigated by means of photophysical characterization, theoretical calculation, device fabrication, and Monte Carlo simulation. The maximum external quantum efficiency of 18.1% with Commission Internationale de L'Eclairage coordinates of (0.61, 0.38) is achieved, which is on par with the state-of-the-art efficiency for red HF-OLEDs. This work presents a feasible design strategy for TADF assistant host aimed at achieving highly efficient HF-OLEDs with narrow-band emission.
10 Jun 13:41
by Guanting Liu,
Hisahiro Sasabe,
Kengo Kumada,
Hiroki Arai,
Junji Kido
Ultra-pure-blue/green OLED: Three types of novel (N−B−O) embedded MR-TADF emitters are successfully developed for high efficiency and narrow emission organic light-emitting devices (OLEDs). In this study, the molecular orbital characters were regulated by adjusting the position of heteroatoms to achieve color-tunable of MR-TADF. The ultra-pure-blue/green devices exhibit high external quantum efficiency over 20 % and narrow full width at half maximum less than 50 nm.
Abstract
In this study, we synthesized and characterized multiresonant thermally activated delayed fluorescent (TADF) materials embedded with nitrogen-boron-oxygen (N−B−O), exhibiting color-tunability between blue and green, namely NBO, m-DiNBO, and p-DiNBO. The three emitter materials showed a high photoluminescence quantum yield (PLQY) and a state-of-the-art narrow full width at half maximum (FWHM) of 96 %/25 nm, 87 %/17 nm, and 99 %/19 nm, respectively. For m-DiNBO and p-DiNBO, the emission color could be tuned from blue to green by regulating the nonbonding/bonding molecular orbital characters. Owing to the expanded planar molecular structure, m-DiNBO and p-DiNBO showed high horizontal dipole ratio (Θ) of 88 % and 92 %, respectively. OLEDs were prepared with NBO, m-DiNBO, and p-DiNBO, exhibiting high external quantum efficiencies of 16.8 %, 24.2 %, and 21.6 %, respectively. NBO and m-DiNBO exhibited pure-blue emission with CIE coordinates of (0.137, 0.142) and (0.126, 0.098), respectively. p-DiNBO showed pure-green emission with a CIE coordinate of (0.258, 0.665).
Open Access
