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This paper proposes a novel pixel circuit and driving scheme that adopts low-temperature polycrystalline silicon and oxide thin-film transistors (LTPO TFTs) for mobile devices using active-matrix organic light-emitting diode (AMOLED) displays. The proposed pixel circuit and driving scheme provide uniform luminance and render flicker invisible at variable refresh rates (VRRs) from 1 to 120 Hz. Using the proposed pixel circuit with extended compensation time (tCOMP) improves the luminance uniformity at a high-frame rate. The proposed driving scheme applies a voltage to the driving TFTs (D-TFTs) higher than the programmed data voltage during the skip frame. This reduces the flicker caused by the hysteresis of D-TFTs during low-frame rate driving. A 6.0-inch quad high-definition (QHD) LTPO-based AMOLED display was fabricated using the new pixel circuit and driving scheme. Experimental results of the proposed pixel circuit show that the standard deviation of luminance was reduced from 0.056 to 0.008 by extending tCOMP from 2 to 8 µs. The flicker level was −51 dB, so there was no visual artifact during 1 Hz driving. A flicker-free LTPO-based AMOLED display with low power consumption is possible; driving can proceed in 1–120 Hz range.

In this research, the use of indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) with a porous oxide layer (POL) resulting from the mechanochemical treatment of spin-coated oxide films is suggested for the detection of visible light. Mechanochemical treatment is a new technique that uses cellophane tape to induce the selective formation of hydrophobic dots on the surface of the a-IGZO. These dots interfere with the deposition of the film during spin coating, resulting in pore formation. The IGZO TFT with a POL exhibits 341.32 A/W photoresponsivity, 1.10 × 106 photosensitivity, and 4.54 × 1010 Jones detectivity under 532 nm light illumination.

Nitrocellulose is proposed as a passivation layer for multilayer molybdenum disulfide (MoS2) thin-film transistors (TFTs) to improve the stability of the devices. After the devised passivation layer was stacked, the threshold voltage shift of the nitrocellulose-passivated MoS2 TFT after the positive-bias temperature stress tests decreased from 11.43 to 4.80 V. This enhanced stability was the result of the protection of the MoS2 channel from external reactive molecules like H2O, O2, and others in the atmosphere. Not only the stability was improved; the electrical performance was also enhanced. The field effect mobility and on/off ratio increased 1.13 and 3.05 times, respectively, due to the narrowed width of the Schottky barrier from the interfacial dipoles between the nitrocellulose and the MoS2 layers. Additionally, the formation of Mo-N bonding generated deep-level subgap states into the bandgap, which led to a higher probability of photoexcitation. Therefore, the MoS2 TFT with a nitrocellulose passivation layer exhibited 202.35 A/W enhanced photoresponsivity, 1.83 × 103 photosensitivity, and 9.94 × 109 Jones detectivity under 635 nm light at 10 mW/mm2.