The electron-transporting materials (ETMs) with excellent electron injection (EI) and electron transporting properties are prerequisites for highly efficient organic light-emitting diodes (OLEDs). In this work, we report a novel ETM, 2,7-di([3,2 `:6 `,3 `'-terpyridin]-4 `-yl)-9,9 `-spirobifluorene (27-mTPSF), which is synthesized by combining electron-withdrawing terpyridine (TPY) moieties with rigid twisted spirobifluorene. This rigid twisted structure helps to maintain the morphological stability of the amorphous film and contributes to the enhancement of the device lifetime. The nitrogen atom at the meta-position on the peripheral pyridine in 27-mTPSF can enhance the horizontal molecular orientation and the electron-transporting property. A green phosphorescent OLED (PhOLED) based on tris[2-(p-tolyl)pyridine]iridium(iii) (Ir(mppy)(3)) as the emitter and 27-mTPSF as ETM displayed a maximum external quantum efficiency (EQE) of 23.1%, and a half-life (T-50) of 77, 4330 and 243 495 h at an initial luminance of 10 000, 1000 and 100 cd m(-2), respectively, which are significantly superior to those of the device based on the conventional ETM 1,3,5-tris(N-phenylbenzimid azol-2-yl-benzene (TPBi). These results indicate a potential application for the ``(A)(n)-D-(A)(n)'' structured terpyridine ETMs.

We studied temperature-dependent amplified spontaneous emission (ASE) in CsPbBr3 perovskite thin films. For temperatures 180-360 K, a narrow-band lasing is observed. However, a new accompanying ASE band appears below 180 K, indicating a more complicated behavior. The two ASE bands are strongly correlated and in competition; they are assigned as exciton and bi-exciton recombination. We estimated the exciton binding energy (E-B = 27.3 meV) and that of the bi-exciton, which is lower than the E-B. The reduced effective mass of the exciton is estimated as mu = 0.11 m(c). This discovery identifies more details of the ASE phenomenon. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

INTRODUCTION Smoking cessation should be part of tuberculosis (TB) treatment, but a cessation service is not available as part of a routine TB service in most low- and middle-income countries. WHO and The International Union Against Tuberculosis and Lung Disease (The Union) issued a guideline and China implemented a pilot project 5 years ago. This study aimed to determine changes in smoking status among TB patients at 5 years after completion of anti-TB treatment to observe long-term outcome of a smoking cessation project whose baseline characteristics were associated with a relapse of smoking behavior. METHODS A prospective longitudinal study was conducted 5 years after completion of anti-TB treatment to assess changes in patient smoking status against individual baseline data that were entered into a database at the time of TB registration. The patients were tracked by trained village doctors and validated by township health staff. Their smoking status was assessed and entered into the database and analysed. RESULTS Of the 800 TB patients registered at baseline, 650 (81.2%) were tracked. Ninety-one (11.4%) patients died and 59 (7.4%) were lost to follow-up. The rates of remaining non-smoking after 5 years were 82.0%, 63.0%, 49.6%, 43.5% and 30.0%, respectively for non-smokers, ex-smokers, current smokers who received cessation intervention, recent quitters, and current smokers not on a cessation intervention. The odds of smoking relapse were significantly higher for those aged >= 65 years (p=0.003) and registered in Xingguo County (p=0.025). CONCLUSIONS Findings from this study confirmed that non-smokers, ex-smokers and current smokers who received cessation intervention at baseline maintained higher non-smoking rates compared with those who did not receive the intervention. To prevent relapse, intensive cessation support should be given to TB patients aged >= 65 years. TB programme managers need to ensure integration and provision of smoking cessation advice and smoke-free policy in routine TB services.

All-inorganic CsPbI2Br perovskite has attracted increasing attention, owing to its outstanding thermal stability and suitable bandgap for optoelectronic devices. However, the substandard power conversion efficiency (PCE) and large energy loss (E-loss) of CsPbI2Br perovskite solar cells (PSCs) caused by the low quality and high trap density of perovskite films still limit the application of devices. Herein, the post-treatment of evaporating cesium bromide (CsBr) is utilized on top of the perovskite surface to passivate the CsPbI2Br-hole-transporting layer interface and reduce E-loss. The results of microzone photoluminescence indicate that the evaporated CsBr gathered at the grain boundaries of CsPbI2Br layers and Br-enriched perovskites (CsPbIxBr3-x, x < 2) are formed, which can provide protection for CsPbI2Br. Therefore, the gaps between crystal grains are filled up, and the recombination loss of the all-inorganic CsPbI2Br PSCs is reduced accordingly. The champion device exhibits high open-circuit voltage and a PCE of 1.271 V and 16.37%, respectively. This is the highest reported PCE among all-inorganic CsPbI2Br PSCs reported so far. In addition, the stability of CsPbI2Br PSCs is effectively improved by CsBr passivation, and the device without encapsulation can retain 86% of its initial PCE after 1368 h of storage, which is beneficial for practical applications.