In this study, we fabricated an organic-metal light-absorbing layer to form a black cathode to improve the display contrast ratio (CR) of organic light-emitting diodes (OLEDs). The proposed black cathode consists of a thin Al layer (10 nm), an organic-metal light-absorbing layer (100 nm) and a thick Al layer (100 nm). The best performance of the organic-metal light-absorbing layer is obtained using a mixture of 25% copper phthalocyanine (CuPc), 25% 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB), and 50% Al. By using this black cathode, the best performance of OLEDs is obtained at an average reflectance of 11.3% and a reflectance variation of 3.3% over the visible spectrum. Moreover, the CR (at 250 cd/m 2 ) is 10.8 under ambient illuminance of 250 lx and 1.23 under a sunny sky of 23,450 lx. The black cathode can realize an increase in conductivity as well as a decrease in the reflection of ambient light, and can also improve both the device performance and the CR. The proposed black cathode has great potential for use outdoors and in high-contrast OLED displays.

In this report, we show that the annealing temperature in QDs/Mg-doped ZnO film plays a very important role in determining QLEDs performance. Measurements of capacitance and single carrier device reveal that the change of the device efficiency with different annealing temperatures is related to the balance of both electron and hole injection. A comparison of annealing temperatures shows that the best performance is demonstrated with 150 °C-annealing temperature. With the improved charge injection and charge balance, a maximum current efficiency of 24.81 cd/A and external quantum efficiency (EQE) of 20.09% are achievable in our red top-emission QLEDs with weak microcavity structure.

The overnight polysomnographic (PSG) recordings of patients were scored by an expert to diagnose sleep disorders. Visual sleep scoring is a time-consuming and subjective process. Automatic sleep staging methods can help; however, the mechanism and reliability of these methods are not fully understood. Therefore, experts often need to rescore the recordings to obtain reliable results. Here, we propose a human-computer collaborative sleep scoring system. It is a rule-based automatic sleep scoring method that follows the American Academy of Sleep Medicine (AASM) guidelines to perform an initial scoring. Then, the reliability level of each epoch is analyzed based on physiological patterns during sleep and the characteristics of various stage changes. Finally, experts would only need to rescore epochs with a low-reliability level. The experimental results show that the average agreement rate between our system and fully manual scorings can reach 90.42% with a kappa coefficient of 0.85. Over 50% of the manual scoring time can be reduced. Due to the demonstrated robustness and applicability, the proposed approach can be integrated with various PSG systems or automatic sleep scoring methods for sleep monitoring in clinical or homecare applications in the future.

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A primary-auxiliary temperature sensing scheme for system-on-a-chip application is proposed in this paper. Taking advantage of the high accuracy and linearity of the analog primary temperature sensors and low production cost of the digital auxiliary temperature sensors, this sensing scheme monitors multiple hotspots in a highly integrated system chip with small area and low power. A cost efficient calibration strategy based on the difference of calibration complexity and sensitivity to the MOSFET aging between the primary and auxiliary temperature sensors is also presented in this paper. Both the temperature sensor prototypes are designed and fabricated with a 90-nm CMOS process technology. The core area of the primary/auxiliary temperature sensors is 0.039/0.001 mm 2 , and consumed energy per conversion is 20.06/0.136 nJ/S with a 1 V supply voltage and 100-kS/s conversion rate. The performance of the temperature sensors and the accuracy improvement of the proposed calibration method are proved with the measurement results.