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Objective: Radiotherapy (RT) is a cornerstone of the glioblastoma (GBM) treatment. However, the resistance of tumour cells to radiation results in early recurrence. The mechanisms underlying GBM radioresistance remain unclear. Screening for differentially expressed genes (DEGs) related to radiation might be a potential solution to this problem. Method: RT‐associated DEGs were screened based on the RNA sequencing of 15 paired primary and recurrent GBMs. The mRNA and protein expression of candidate genes were validated in RNA sequencing of The Chinese Genome Atlas (CGGA) dataset and 18 cases of GBM samples. The relationship between the candidate gene and radiation was confirmed in irradiated GBM cells. The association of candidate gene with clinical characteristics and survival was investigated in the CGGA and TCGA dataset. Biological function and pathway analysis were explored by gene ontology analysis. The association of the candidate gene with radiosensitivity was verified using cell counting Kit‐8, comet, and colony formation assays in vitro and subcutaneous tumour xenograft experiments in vivo. Results: Gelsolin (GSN) was selected for further study. GSN expression was significant elevated in recurrent GBM and up‐regulated in irradiated GBM cell lines. High expression of GSN was enriched in malignant phenotype of glioma. Moreover, high expression of GSN was associated with poor prognosis. Further investigation demonstrated that GSN‐knockdown (GSN‐KD) combined with RT significantly inhibited cell proliferation and enhanced radiosensitivity in vivo and in vitro. Mechanistically, GSN‐KD could lead to more serious DNA damage and promotes apoptosis after RT. Conclusion: Radiation induced up‐regulated of GSN. GSN‐KD could enhance the radiosensitivity of GBM. [ABSTRACT FROM AUTHOR]

In coal mines, the effective extraction of relief gas and the prevention of dynamic disasters depend on accurate predictions of the spatial distribution of mining stress in the overlying rock. However, at present, the prediction of stress relief and concentration zones based on operational experience or empirical modeling differs significantly from actual measurements in the field. The fundamental problem is the difficulty in modeling the transfer mechanism of the mining overburden load under the influence of key strata. In this study, a mechanical model of the spatial distribution of the mining stress field based on the structure of overburden key strata was established. The model demonstrates that the key strata are the main bearing bodies of the overlying rock, both before and after the fracture, and the overburden rock load can be transferred to the coal and rock mass around the stope through the key strata in the fracture and bending subsidence zones, thus forming a mining stress field. Equations for calculating the plane distributions of mining stress under the key strata at different horizons and abutment pressures on the stope were established, and a spatial distribution prediction method for the mining stress field based on the overburden key strata structure was proposed. The study area was the Gaojiapu Coal Mine, where it was found that the key stratum of the 400.45 m thick Luohe Formation sandstone bore most of the overlying rock load and transferred the load to the coal and rock mass around the stope. This load distribution is the root cause of a high concentration and wide influence range of mining stresses, leading to serious deformation of the main roadway and frequent dynamic disasters. The mining stress concentration was maximized at a mining length of 1458 m × 1458 m. [ABSTRACT FROM AUTHOR]

Intrinsically stretchable light‐emitting polymer semiconductors are essential building blocks for bioelectronics and display textiles. Stretchability is challenging for rigid conjugated polymers unless sacrificing charge mobility by introducing amorphous domains. High‐performance light‐emitting properties designed with twisted angle are undesirable for conductive materials. Hence, the concurrent strategies hardly satisfy the balance of stretchability, light‐emitting and mobility. Herein, a morphology engineering is proposed by controlling micro‐crystalline and limiting aggregation, that four intrinsically stretchable emissive polymers with good charge mobility based on indacenodithiophene (IDT) are obtained. Polymers reveal good emission properties with high photoluminescence quantum yields (PLQY) of about 20%, while stretchable modulus and charge mobility are tunable by backbone and weight. Specifically emphasizing, IDT‐2T‐H retains high performance of charge mobility and PLQY even at 100% strain. Therefore, organic light emitting diodes are fabricated based on it and showing the luminance of 176.2 cd cm−2, which verifies the potential of technique to reconcile integration of stretchability, light‐emitting, and mobility. This is the first attempt to integrate balanced mechanical, optical, and electrical properties through micro‐crystalline aggregation‐limited morphology in one polymer, offering a feasible approach to advanced integrated circuit and multi‐functional electronics in the future. [ABSTRACT FROM AUTHOR]

Aerobic glycolysis is critical for the energy metabolism of cancer cells. This study focuses on the regulation of forkhead box A2 (FOXA2) on pyruvate kinase M2 (PKM2) and their effects on the glycolytic activity and malignant phenotype of thyroid carcinoma (THCA) cells. By analysing four Gene Expression Omnibus datasets and querying bioinformatics systems, we obtained FOXA2 as a poorly expressed transcription factor in THCA. Later, we validated decreased mRNA and protein levels of FOXA2 in THCA cells by quantitative polymerase chain reaction and western blot assays. FOXA2 upregulation in THCA cells suppressed the glucose uptake and lactate production, and it reduced the extracellular acidification rate, but increased the oxygen consumption rate of cells. Meanwhile, the FOXA2 overexpression blocked the proliferation and mobility, and the tumourigenic activity of cancer cells. The chromatin immunoprecipitation and luciferase assays showed that FOXA2 bound to PKM2 promoter and suppressed the transcription of PKM2, which was highly expressed in THCA cells. Further upregulation of PKM2 elevated the β‐catenin, c‐Myc and cyclin D1 levels and restored the glycolytic activity as well as the malignant properties of cancer cells. Collectively, this work reveals that FOXA2 suppresses aerobic glycolysis and progression of THCA by blocking PKM2 transcription and inactivating the Wnt/β‐catenin pathway. [ABSTRACT FROM AUTHOR]

Flexible organic monitoring system that can work in short‐wave infrared (SIR) region has great potential in autonomous driving, night driving safety, military encryption, biomedical imaging, and robot engineering. Especially, the development of infrared artificial vision system device that can autonomously improve the computing speed and adapt to different brightness ambient light is very important. However, it is a challenge for mimicking infrared visual adaptation because of the need for infrared absorbing materials and the need to control the concentration of carriers. In this study, inorganic quantum dot material is combined with organic materials to promote carrier separation and introduce interface defects that adjust the carrier concentration in transistors, which induce the synaptic behavior under SIR (1100 nm) light in darkness and the ability to adapt to white ambient light. Furthermore, the device array realizes the image recognition of SIR light at night with white ambient light of different brightness, exhibiting good self‐adaptability, and strong anti‐interference ability. These results demonstrate promising applications of the infrared synaptic phototransistors in adapted bionic optoelectronic devices. [ABSTRACT FROM AUTHOR]

The development of polymer semiconductors with strong luminescence and high mobility has always been challenging, and achieving both properties together is considered paradoxical according to molecular design principles. Studies on novel molecular species with unique optoelectrical characteristics are limited. Herein, a novel fully rigid coplanar thiophene‐pyridal[1,2,3]triazole‐thiophene (T‐PT‐T) class structure with considerable intramolecular noncovalent interactions is proposed. To balance luminescence and carrier transport properties, a series of non‐conventional regioregular conjugated polymers (PPTs) with suitable energy gaps (Egs ≈ 1.8 eV) are developed, which exhibit near‐infrared (NIR, 700–1000 nm) light emission and high mobility. One of the synthesized polymers, PPT‐2, exhibits an excellent photoluminescence quantum yield (PLQY) of 9% in the solid‐state and a high mobility reaching 0.35 cm2 V−1 s−1, indicating superior performance compared to other NIR light‐emitting polymer semiconductors. The authors believe that the class structure of fully rigid coplanar "T‐PT‐T" could be harnessed to develop high‐mobility NIR light‐emitting polymer semiconductors. [ABSTRACT FROM AUTHOR]

Bioinspired electronics have shown great potential in the field of artificial intelligence and brain‐like science. Low energy consumption and multifunction are key factors for its application. Here, multisensory artificial synapse and neural networks based on electrolyte‐gated vertical organic field‐effect transistors (VOFETs) are first developed. The channel length of the organic transistor is scaled down to 30 nm through cross‐linking strategy. Owing to the short channel length and extremely large capacitance of the electric double layer formed at the electrolyte–channel interface, the minimum power consumption of one synaptic event is 0.06 fJ, which is significantly lower than that required by biological synapses (1–10 fJ). Moreover, the artificial synapse can be trained to learn and memory images in a 5 × 5 synapse array and emulate the human brain's spatiotemporal information processing and sound azimuth detection. Finally, the artificial tongue is designed using the synaptic transistor that can discriminate acidity. Overall, this study provides new insights into realizing energy‐efficient artificial synapses and mimicking biological sensory systems. [ABSTRACT FROM AUTHOR]

Background: The radiation dose for patients with low‐grade gliomas (LGGs) is controversial. The objective of this study was to investigate the impact of the radiation dose on survival for patients with LGGs and especially for molecularly defined subgroups. Methods: Three hundred fifty‐one patients with newly diagnosed LGGs from the multicenter Chinese Glioma Cooperative Group received postoperative radiotherapy (RT) in 2005‐2018. The RT dose, as a continuous variable, was entered into a Cox regression model using penalized spline regression to allow for a nonlinear relationship between the RT dose and overall survival (OS) or progression‐free survival (PFS). Inverse probability of treatment weighting (IPTW)–adjusted propensity scores were used to correct for potential confounders. Dose effects on survival within IDH mutation and 1p/19q codeletion defined subgroups were analyzed. Results: The risk of mortality and disease progression decreased sharply until 54 Gy. High‐dose RT (≥54 Gy) was associated with significantly better 5‐year OS (81.7% vs 64.0%; hazard ratio [HR], 0.33; P <.001) and PFS (77.4% vs 54.5%; HR, 0.46; P <.001) than low‐dose RT (<54 Gy). IPTW correction confirmed the associations (HR for OS, 0.44; P =.001; HR for PFS, 0.48; P =.003). High‐dose RT was associated with longer PFS (HR, 0.25; P =.002; HR, 0.21; P =.039) and OS (HR, 0.27; P =.006; HR, 0.07; P =.017) in IDH‐mutant/1p/19q noncodeleted and IDH wild‐type subgroups, respectively. No significant difference in survival was observed with high‐dose RT in the IDH‐mutant/1p/19q codeleted subgroup. Conclusions: High‐dose RT (≥54 Gy) was effective in LGGs. Patients with an IDH mutation/1p/19q noncodeletion or IDH wild‐type may need to be considered for high‐dose RT. Lay Summary: The radiotherapy dose‐response was observed in patients with low‐grade gliomas, and high‐dose radiotherapy (≥54 Gy) was associated with improved survival.Patients with an IDH mutation/1p/19q noncodeletion or wild‐type IDH may have improved survival with the administration of high‐dose radiotherapy. High‐dose radiotherapy (≥54 Gy) is an independent protective factor for overall survival and progression‐free survival in low‐grade gliomas. Patients with an IDH mutation/1p/19q noncodeletion or IDH wild‐type benefit from high‐dose radiotherapy. [ABSTRACT FROM AUTHOR]

The solution‐handling characteristics of π‐conjugated polymer semiconductors make them promising candidates for low‐cost flexible electronics. Although homogeneous and stable nonchlorine solvent (NClS) processing is the only way that must be passed for future application, polymer semiconductors still meet the challenges of poor solubility and inhomogeneities in NClS. Here, the authors primp polymer molecules with protonic acid by multiple interactions, that is, proton exchange and hydrogen bond interaction, to achieve scale and model‐constrained PDVT‐10c assembly in NClS. As a result, a uniform near‐amorphous PDVT‐C10c film is developed for polymer thin‐film transistor (PTFT) array, which exhibits uniform performance with much narrower Gaussian standards deviation than pristine PDVT‐C10c one. Finally, a 5 cm × 5 cm PTFT as the active‐matrix circuit for blue organic light‐emitting diode is demonstrated. The results illustrate the great potential of protonic acid‐mediated molecular self‐assembly on homogeneous and stable NClS processing polymer semiconductors for next‐generation flexible electronics. [ABSTRACT FROM AUTHOR]

Background: PTPRZ1‐MET (ZM) is a critical genetic alteration driving the progression of lower‐grade glioma. Glioma patients harboring ZM could benefit from MET inhibitors. According to the remarkable role of ZM as a driver of glioma progression and indicator of MET inhibitor sensitivity, it is necessary to detect this alteration even when it presents in glioma with relatively fewer copies. Methods: Herein, we proposed that ZM could be detected with a high‐sensitive method of reverse transcriptase PCR with 50 amplification cycles. Via this newly proposed detection method, we depicted the incidence preference of ZM fusion in a cohort of 485 glioma patients. To further explore the oncogenic nature of ZM, we predicated the protein structure alteration of MET kinase brought by its fusion partner. Results: The incidence of ZM fusions was much higher than previous report. ZM fusions exhibited a striking preference in lower‐grade glioma and secondary glioblastoma. By contrast, none of patients with primary glioblastoma was detected harboring ZM fusion. In each of the four variants of ZM, the fusion partner segment of MET contained a remarkable coiled‐coil motif. In glioma cells expressing ZM, MET kinase could be activated in a ligand‐independent manner, which might be contributed by the special coiled‐coil structure brought by the fusion partner. Corresponding to the 3D structural analysis and cell line experiment, the ZM positive clinical specimens showed hyperactivations of MET signaling. Conclusions: ZM fusions are critical drivers of glioma progression and effective target of MET inhibitor. Early detection could be performed with a high‐sensitive method of reverse transcriptase PCR. The hyperactivations of MET signaling driving glioma progression might be contributed by a ligand‐independent activation enabled by the protein structure modification of extracellular domain of MET in ZM fusions. [ABSTRACT FROM AUTHOR]

Background: RGS protein family members have recently became new potentially promising therapeutic targets in many cancers. However, as a key member of RGS family, RGS16 has seldom been studied in glioma. The present study was designed to investigate the prognostic value and biological function of RGS16 based on large‐scale databases and functional assays in vitro. Methods: Here, we performed comprehensive analysis for the expression characteristic of RGS16 in Chinese Glioma Genome Atlas (CGGA) microarray database with 301 patients and validated in The Cancer Genome Atlas (TCGA) microarray and RNA sequencing database. Student's t‐test, one‐way ANOVA test and long‐rank test were used to assess differences between groups. Kaplan‐Meier survival, univariate and multivariate Cox analysis and ROC curve were used to estimate the survival distributions. Biological implication of abnormal expression of RGS16 in glioma was also explored. Functional analysis of RGS16 was performed in several glioblastoma (GBM) cell lines. R language and SPSS were used for statistical analysis and graphical work. Results: We found that the expression of RGS16 was positively related to the grade of glioma. High level of RGS16 commonly gathered in glioma of mesenchymal subtype and wild‐type IDH1. Moreover, higher expression level of RGS16 was found to be significantly correlated with poor prognosis. The univariate and multivariate Cox regression analysis and ROC curve showed that RGS16 was an independent prognostic factor for glioma patients. Gene ontology analysis, gene set enrichment analysis, and gene set variation analysis suggested that the overexpression of RGS16 tightly related to cell proliferation, migration, epithelial‐mesenchymal transition (EMT), immune and inflammatory response of glioma. Knockdown of RGS16 in glioma cell lines also showed that RGS16 promoted the malignant progress of glioma cell lines. Conclusions: RGS16 plays an important role in glioma progression and serves as an independent prognostic factor, especially in GBM patients. [ABSTRACT FROM AUTHOR]

Coal and gas outburst is one of the most harmful natural disaster in coal mine production. The frequency and scope of outburst are closely related to the metamorphic degree of coal seam, the depth of coal seam, and the complexity of geological structure. In general, the use of traditional along‐seam borehole or cross‐seam borehole can meet the needs of gas control. However, for the coal seams with high outburst risk, these methods fail to meet the demands of high‐yield and high‐efficiency coal recovery as well as safe, green, and economical coal mining. Although pressure‐relief gas extraction in the protective seam and coalbed methane (CBM) pre‐extraction can eliminate outburst risk in coal seams, these methods can hardly help realize the green development trend of coal and CBM co‐extraction because they cannot guarantee the current situation of highly mechanized mining. In this study, a three‐dimensional coal and CBM co‐extraction strategy was proposed. The strategy includes three levels of three‐dimensional gas prevention and control methods. The first level is the combination of ground and underground gas extraction methods, to achieve joint extraction of ground and underground gas. The second level is the full‐coverage extraction of the coal resources to be mined, to achieve joint extraction through upper and lower cross‐seam borehole and along‐seam borehole. The third level is the optimization of ground and underground extraction and utilization systems, to realize the full utilization of CBM and to achieve the goal of coal and CBM co‐extraction. The three‐dimensional gas prevention and control method constructs a new gas control model for single thick coal seams with high gas outburst risk and realizes the all‐round coordination and unity of different gas control methods spatially and temporally. The gas control strategy completely eliminates the high gas outburst risk of a single thick coal seam and has been successfully applied in Hudi Coal Mine. The application results verify that the method can effectively guarantee the operation safety during highly mechanized mining, realize extraction and full utilization of separate‐source gas, and provide guidance and direction for coal and CBM co‐extraction with similar extraction conditions. [ABSTRACT FROM AUTHOR]

Background: To investigate the clinical efficacy and mechanism of laparoscopic sleeve gastrectomy (LSG) in improving renal function in obese patients. Methods: We retrospectively reviewed the anthropometric indices (waist circumference, hip circumference and body mass index (BMI)), renal function indices (serum creatinine, urea and urinary albumin:creatinine ratio (UACR)), serum inflammatory indices (C‐reactive protein, interleukin‐6 and tumour necrosis factor‐α) and an adipose factor (leptin) in 50 patients with obesity (BMI ≥32.5 kg/m2) who underwent LSG in our hospital from January 2018 to January 2019. Results: Patients constituted 23 men and 27 women, with an average age of 32.5 ± 8.7 years and BMI of 43.99 ± 8.29 kg/m2. Body weight and BMI 1 month post‐operatively were significantly lower than preoperatively (P < 0.05), and the renal function indices serum creatinine, urea and UACR, improved significantly 3 months post‐operatively (P < 0.05). C‐reactive protein, interleukin‐6 and tumour necrosis factor‐α levels improved significantly 3 months post‐operatively (P < 0.05), while leptin levels decreased significantly 1 month post‐operatively (P < 0.05). Six months post‐operatively, the remission rates for type 2 diabetes mellitus, sleep apnoea syndrome and hypertension were 83.8%, 92.9% and 88.6%, respectively. Conclusions: LSG led to body weight loss and significantly improved serum creatinine, urea and UACR values in patients with obesity, which may be related to changes in adipocytokines and inflammatory factors, post‐operatively. LSG is expected to become a new treatment to prevent or treat renal insufficiency caused by obesity. [ABSTRACT FROM AUTHOR]

Wavefront sensing at X‐ray free‐electron lasers is important for quantitatively understanding the fundamental properties of the laser, for aligning X‐ray instruments and for conducting scientific experimental analysis. A fractional Talbot wavefront sensor has been developed. This wavefront sensor enables measurements over a wide range of energies, as is common on X‐ray instruments, with simplified mechanical requirements and is compatible with the high average power pulses expected in upcoming X‐ray free‐electron laser upgrades. Single‐shot measurements were performed at 500 eV, 1000 eV and 1500 eV at the Linac Coherent Light Source. These measurements were applied to study both mirror alignment and the effects of undulator tapering schemes on source properties. The beamline focal plane position was tracked to an uncertainty of 0.12 mm, and the source location for various undulator tapering schemes to an uncertainty of 1 m, demonstrating excellent sensitivity. These findings pave the way to use the fractional Talbot wavefront sensor as a routine, robust and sensitive tool at X‐ray free‐electron lasers as well as other high‐brightness X‐ray sources. [ABSTRACT FROM AUTHOR]

The current research of platinum (Pt)–based catalysts focuses on reducing Pt loading in the catalysts while enhancing the catalytic activity. As a rare‐earth element, lanthanum (La) has demonstrated good synergistic effect with Pt‐based catalysts, because of its catalytic promoting capability and high dispersibility. Here, we fabricated La‐doped nano‐Pt‐based catalytic membrane electrode using ion beam sputtering method. The effect of La on the morphology and electrochemical performance of the catalytic membrane electrode was investigated by scanning electron microscope, X‐ray photoelectron spectroscopy, and electrochemical measurements. Compared with pure Pt‐based sample, the electrochemical activity specific area of the La‐doped sample increases by 74.59%, with 63.95% increase in exchange current density. The results also show that La2O3 enhances oxygen enrichment of the membrane electrode and reduces interfacial energy among Pt grains while pinning the grain boundaries. In addition, the inductively coupled plasma atomic emission spectroscopy (ICP‐AES) measurement shows that the Pt loading in the membrane electrodes is below 0.1 mg/cm2. Thus, enhanced catalytic performance is achieved in catalysts with lower Pt loading. [ABSTRACT FROM AUTHOR]

Here a direct comparison is made between various X‐ray wavefront sensing methods with application to optics alignment and focus characterization at X‐ray free‐electron lasers (XFELs). Focus optimization at XFEL beamlines presents unique challenges due to high peak powers as well as beam pointing instability, meaning that techniques capable of single‐shot measurement and that probe the wavefront at an out‐of‐focus location are desirable. The techniques chosen for the comparison include single‐phase‐grating Talbot interferometry (shearing interferometry), dual‐grating Talbot interferometry (moiré deflectometry) and speckle tracking. All three methods were implemented during a single beam time at the Linac Coherent Light Source, at the X‐ray Pump Probe beamline, in order to make a direct comparison. Each method was used to characterize the wavefront resulting from a stack of beryllium compound refractive lenses followed by a corrective phase plate. In addition, difference wavefront measurements with and without the phase plate agreed with its design to within λ/20, which enabled a direct quantitative comparison between methods. Finally, a path toward automated alignment at XFEL beamlines using a wavefront sensor to close the loop is presented. [ABSTRACT FROM AUTHOR]

Gliomas are the most common malignant tumors of the brain. Immune checkpoints have been increasingly emphasized as targets for treating malignant tumors. B7‐H3 has been identified as an immune checkpoint that shows potential value for targeting therapies. We set out to characterize the expression pattern and biological function of B7‐H3 in brain gliomas using high‐throughput data obtained from the Chinese Glioma Genome Atlas (CGGA) and the Cancer Genome Atlas (TCGA) projects. B7‐H3 was upregulated more in higher‐grade gliomas than that in lower‐grade gliomas in both CGGA and TCGA datasets. Isocitrate dehydrogenase (IDH) mutation seemed to exert significant influence on B7‐H3 expression in gliomas but led to quite different results between grade II gliomas and higher‐grade gliomas. In addition to IDH, methylation of B7‐H3 promoter and microRNA‐29 family also showed a potential regulatory effect on B7‐H3 expression. Gene ontology analysis revealed that B7‐H3 was associated with mitotic cell cycle, cell proliferation and immune response. Further investigation suggested that B7‐H3 was mostly involved in the Toll‐like receptor signaling pathway. Survival analysis indicated that B7‐H3 was an independent unfavorable prognosticator for glioma patients in both CGGA and TCGA datasets. B7‐H3 expression is regulated by multiple mechanisms and is potentially involved in the T‐cell receptor signaling pathway. Higher B7‐H3 expression indicates a worse prognosis for glioma patients, which warrants further research into the development of inhibitors for targeting this immune checkpoint, but we still need to be cautious about immune checkpoint inhibition for central nervous system tumors. [ABSTRACT FROM AUTHOR]

Aromatic-imide-based thermally activated delayed fluorescence (TADF) materials with a twisted donor-acceptor-donor skeleton were efficiently synthesized and exhibited excellent thermal stability and high photoluminescence quantum yields. The small Δ EST value (<0.1 eV) along with the clear temperature-dependent delayed component of their transient photoluminescence (PL) spectra demonstrated their excellent TADF properties. Moreover, the performance of organic light-emitting diodes in which TADF materials AI-Cz and AI-TBCz were used as dopants were outstanding, with external quantum efficiencies up to 23.2 and 21.1 %, respectively. [ABSTRACT FROM AUTHOR]

Four donor–acceptor–donor region isomers (2,3‐TXO‐PhCz, 2,6‐TXO‐PhCz, 2,7‐TXO‐PhCz, and 3,6‐TXO‐PhCz) are designed. The substitution positions of the two PhCz units significantly impact the photophysical properties of the isomers, especially for the singlet–triplet energy splitting (ΔEST) and oscillator strength (f ). 2,3‐TXO‐PhCz exhibits weak emission due to the large steric hindrance of the two PhCz units. While 2,6‐TXO‐PhCz, 2,7‐TXO‐PhCz, and 3,6‐TXO‐PhCz all exhibit strong emission. The four emitters possess small ΔEST of 0.01–0.24 eV; the corresponding f values are 0.064, 0.107, 0.026, and 0.134. Consequently, the photoluminescence quantum yields (PLQYs) of the doped films in CBP host are: 62.1% for 2,3‐TXO‐PhCz, 83.8% for 2,6‐TXO‐PhCz, 89.0% for 2,7‐TXO‐PhCz, and 85.4% for 3,6‐TXO‐PhCz. Although notable divergences of f and ΔEST exist between 2,6‐TXO‐PhCz and 2,7‐TXO‐PhCz, similar PLQY of doped film in the CBP host, and exciton utilization and external quantum efficiency (EQE) of the corresponding devices can be achieved: 2,6‐TXO‐PhCz and 2,7‐TXO‐PhCz endow the organic light‐emitting devices with high EQE of 23.2% and 24.4%. This proximity can be attributed to the synergistic effect of f and ΔEST. This finding highlights the beneficial role of the different linking positions on the acceptor unit in facilitating the adjustment of f and ΔEST in order to improve the device efficiency. [ABSTRACT FROM AUTHOR]

Contradiction between no effective photophysical experiments and high device results causes the "hot exciton" thermally activated delayed fluorescence (TADF) mechanism to be still a controversial question. Here, the steady and transient photophysical characterization combined with theoretical calculation based on 4,7‐bis(9,9‐dimethyl‐9H‐fluoren‐2‐yl)‐5,6‐difluorobenzo [c][1,2,5]thiadiazole (2F‐BTH‐DMF), 4,7‐bis(9,9‐dimethyl‐9H‐fluoren‐2‐yl)benzo[c][1,2,5]thiadiazole (BTH‐DMF), and 5,6‐bis(9,9‐dimethyl‐9H‐fluoren‐2‐yl)benzo[c][1,2,5] thiadiazole (o‐BTH‐DMF) demonstrate that all the emitters exhibit TADF via reverse intersystem crossing (RISC) from "hot exciton" triplet excited state. The fast RISC process "hot exciton" mechanism affords a very short delayed lifetime (1 µs). Organic light‐emitting diodes (OLEDs) based on these emitters exhibit high exciton utilization over 25% and the best device shows a maximum current efficiency of 31.02 cd A−1, maximum power efficiency of 27.85 lm W−1, and external quantum efficiency of 9.13%, which are the highest performances for reported OLEDs with "hot exciton" mechanism. The experimental evidence for fast RISC process via "hot exciton" triplet state and short delayed lifetime highlights the TADF emitters with "hot exciton" mechanism for high‐performance OLEDs with very low efficiency roll‐off. The "hot exciton" thermally activated delayed fluorescence (TADF) compounds BTH‐DMF, 2F‐BTH‐DMF and o‐BTH‐DMF are designed and proved by steady and transient photophysical characterization combined with theoretical calculation. Organic light‐emitting diodes (OLEDs) based on BTH‐DMF (4,7‐bis(9,9‐dimethyl‐9H‐fluoren‐2‐yl)benzo[c][1,2,5]thiadiazole) exhibit high exciton utilization over 25%, high device performance, and low efficiency roll‐off, which are highest performances reported for "hot exciton" OLEDs. [ABSTRACT FROM AUTHOR]

Spectral stability and high color rendering index (CRI) remain challenges to high‐performance, solution‐processed white organic light‐emitting devices (WOLEDs) based on two complementary colors. The solution‐processed WOLED based on two thermally activated delayed fluorescence emitters with complementary color, i.e., the orange–red 2‐[4‐(diphenylamino) phenyl]‐10,10‐dioxide‐9H‐thioxanthen‐9‐one emitter and the blue 4,4′‐bis(carbazol‐9‐yl)‐2,2′‐dimethylbiphenyl:4,6‐bis(3,5‐di(pyridin‐4‐yl)phenyl)‐2‐phenylpyrimidine interface exciplex, is reported here. Poly[(9,9‐dioctylfluorenyl‐2,7‐diyl)‐co‐(4,4′‐(N‐(4‐sec‐butylphenyl)) diphenylamine)] is doped with 30 wt% cross‐linkable N,N′‐(4,4′‐(cyclohexane‐1,1‐diyl)bis(4,1‐phenylene))bis(N‐(4‐(6‐(2‐ethyloxetan‐2‐yloxy)hexyl)phenyl)‐3,4,5‐trifluoroaniline) to form a smooth hole transportation layer with outstanding solvent resistance ability and efficient hole transporting/injection ability. The position of interface exciplex and exciton management in the emitting layer can be tuned, thus anchoring the color stability. The device displays a maximum external quantum efficiency of 10.02% and a high CRI of 85 with Commission Internationale de l'Eclairage (CIE) color coordinates of (0.32, 0.33) at the luminescence of 1000 cd m−2. These results are among the best of solution‐processed WOLEDs based on two complementary chromophores. A highly efficient, solution‐processed two‐color white organic light‐emitting device is developed on two thermally activated delayed fluorescence emitters, the orange–red 2‐[4‐(diphenylamino) phenyl]‐10,10‐dioxide‐9H‐thioxanthen‐9‐one emitter and the blue 4,4′‐bis(carbazol‐9‐yl)‐2,2′‐dimethylbiphenyl:4,6‐bis(3,5‐di(pyridin‐4‐yl)phenyl)‐2‐phenylpyrimidine interface exciplex, with hole transport polymers assisted by the cross‐linked matrix. The position of the interface exciplex and exciton management in the emitting layer can be finely tuned to anchor the color stability and induce a high color rendering index of 85. [ABSTRACT FROM AUTHOR]