Yi Li,Hongde Luo,Longmei Mao,Longxin Yu,Xifeng Li,Libo Jin,Jianhua Zhang
In this study, p-type delafossite CuCrO 2 nanomaterials are synthesized via a one-step hydrothermal reaction. An organic photodiode (OPD) with an inverted stack is fabricated by utilizing such CuCrO 2 as the hole-transporting layer. The single OPD device shows the dark current density of 6.48 × 10 −8 A cm −2 , and an external quantum efficiency of 16.2% at a 525 nm illumination, and a −5 V bias. Its responsivity and detectivity are 68.5 mA W− 1 and 4.75 × 10 11 cm Hz 1/2 W −1 , respectively. A large-area, flat-panel image sensor is also realized similarly by applying the materials and structure onto a thin-film transistor backplane. The active area and pitch of flat-panel sensor are 75.0 mm × 81.0 mm and 150 µm, respectively and its resolution is 510 × 470. The performance of the organic image sensor is evaluated. The results indicate the materials and device have potential applications for the flat-panel detector.
Chalcogenide Cu 2 ZnSn(S,Se) 4 (CZTSSe) is a promising absorber material for photovoltaic applications. When CZTSSe thin film is deposited on an Mo substrate, a Mo(S,Se) 2 layer easily forms between the CZTSSe and the Mo, which is detrimental to the back contact property of the CZTSSe. This work proposes a useful way to inhibit the formation of Mo(S,Se) 2 by sputtering a CuCrO 2 layer on a Mo-foil substrate before the deposition of the CZTSSe. The effects of CuCrO 2 thickness on the crystalline structures, morphologies, and electrical properties of the fabricated samples were studied. The results showed that the insertion of the CuCrO 2 layer prevented the formation of Mo(S,Se) 2 . As the thickness of the CuCrO 2 increased, the thickness of the Mo(S,Se) 2 layer decreased. The Mo(S,Se) 2 layer was absent from the cross-sectional scanning electron microscopy image when the CuCrO 2 thickness exceeded 85 nm. The back contact resistance of CZTSSe decreased monotonously as the CuCrO 2 layer thickened due to the reduction in the Mo(S,Se) 2 layer thickness. Therefore, by inserting a CuCrO 2 layer to separate the CZTSSe and the Mo-foil, the formation of the Mo(S,Se) 2 layer between them was effectively suppressed, and the back contact properties of the CZTSSe thin film were significantly enhanced.
In this study, transparent p-type CuCrxOy semiconductor thin films were fabricated using spin coating and integrated as channel layers in thin-film transistors (TFTs). The structural, morphological components, and optical properties of CuCrxOy thin films, together with device performance, were systematically investigated. The phase conversion from a mixture of CuCr2O4 and CuO to pure CuCrO2 was achieved when the annealing temperature (Ta) was higher than 700 °C. The electrical performance of the CuCrxOy TFTs on SiO2 dielectric is improved with increasing Ta from 500 °C to 800 °C. The optimized CuCrO2 TFT exhibits an on/off current ratio of ∼105 and a hole mobility of 0.59 cm2 V−1 s−1, which is much better than those previous works on solution-processed binary CuxO TFTs. To our best knowledge, this work demonstrates the ternary p-type CuCrO2 TFTs fabricated via a low-cost solution process for the first time, which represents an important advancement towards the development of all-oxide, low-cost p–n junctions and CMOS logic circuits.