We have investigated trap density of states (trap DOS) in n-channel organic field-effect transistors based on N,N ’-bis(cyclohexyl)naphthalene diimide (Cy-NDI) and dimethyldicyanoquinonediimine (DMDCNQI). A new method is proposed to extract trap DOS from the Arrhenius plot of the temperature-dependent transconductance. Double exponential trap DOS are observed, in which Cy-NDI has considerable deep states, by contrast, DMDCNQI has substantial tail states. In addition, numerical simulation of the transistor characteristics has been conducted by assuming an exponential trap distribution and the interface approximation. Temperature dependence of transfer characteristics are well reproduced only using several parameters, and the trap DOS obtained from the simulated characteristics are in good agreement with the assumed trap DOS, indicating that our analysis is self-consistent. Although the experimentally obtained Meyer-Neldel temperature is related to the trap distribution width, the simulation satisfies the Meyer-Neldel rule only very phenomenologically. The simulation also reveals that the subthreshold swing is not always a good indicator of the total trap amount, because it also largely depends on the trap distribution width. Finally, band transport is explored from the simulation having a small number of traps. A crossing point of the transfer curves and negative activation energy above a certain gate voltage are observed in the simulated characteristics, where the critical VG above which band transport is realized is determined by the sum of the trapped and free charge states below the conduction band edge

The screen door effect (SDE) is the great challenge in the development of VR display, which obstructs immersion in the virtual reality. In this paper, we propose the quantitative investigation method for SDE, and demonstrate how the SDE can be systematically mitigated without degrading image quality. Author KeywordsVirtual Reality; Screen Door Effect; OLED; Low-pass filter Objective and BackgroundVirtual Reality (VR) devices have attracted huge interest from industries in anticipation of numerous applications for entertainment, education, medical uses and so on [1]. As VR hardware becomes more affordable, it has come into wide use. By wearing a VR headset, we are immediately surrounded by realistic scenery projected by head-mounted display. Many technologies are required for making the immersive experience in VR headsets; however, display technology is critical because it is directly related to our vision. Figure 2. Microscopic images (X50) is shown (a) without and (b) with the SDE reduction film.

Transistors based on single crystalline films of 2-decyl-7-phenyl-[1]benzothieno[3,2b][1]benzothiophene (Ph-BTBT-10) fabricated using the blade-coating method are investigated by the four-probe method down to low temperatures. The four-probe mobility is as large as 18 cm 2 /Vs at room temperature, and increases to 45 cm 2 /Vs at 80 K. At 60 K the two-probe mobility drops abruptly by about 50%, but the mobility drop is mostly attributed to the increase of the source resistance. The carrier transport in the present single crystalline film is regarded as essentially band-like down to 30 K.

Ambipolar organic transistors based on dicyanomethylene terthiophene show electron and hole mobilities of up to 0.6 and 0.3 cm2 V−1 s−1, respectively, on tetratetracontane, which are thousands of times larger than the reported value. The intrinsic electron and hole threshold voltages are determined by analyzing the output and transfer characteristics, from which the ambipolar characteristics are quantitatively reproduced. Since the transistor is operated mostly in the unipolar region, the trap density of states is estimated from the temperature dependence of the transfer characteristics.

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