Printed electronics is a manufacturing technology that fabricates electronic devices using printing techniques. Due to its characteristics of low cost and simple process, a roll-to-roll printing technique has been used to achieve the large area and mass production of flexible electronic devices such as a thin film transistor. In the roll-to-roll printing process, a fidelity of the engraved pattern position is one of the most important techniques to fabricate high resolution multi-layer electronic devices. In this study, an engraved register mark position measurement system was developed to numerically evaluate the position accuracy of engraved mark in printing roll. The proposed system is based on a high-precision encoder based position control system and a high-resolution machine vision system. The measurement error of the developed system is within the camera resolution ±2.1 μm, verifying the superiority of the system. Using the developed system, we measured the position errors of the engraved register marks for six industrial scale printing rolls. This study suggests that the position error of the engraved mark should be considered to achieve a high precision register control below ±10 μm and necessity of the developed system.

Among the various next-generation solar cells, a perovskite solar cell can solve the economic problem because it can perform the low temperature solution process and the material is inexpensive. Photovoltaic conversion efficiency is comparable to silicon solar cells and thin-film solar cells. However, to commercialize the perovskite solar cells, there are many problems to be resolved, such as stability, upscaling, and efficiency. Thus, in this study, perovskite crystallization experiments were conducted according to the coating conditions such as the coating speed of the meniscus solution sheared coating process, and large-area perovskite solar cells with p-i-n structures were fabricated. Perovskite crystallization is one of the crucial factors that determine the efficiency of solar cells, and it is an integral process condition for manufacturing large-area perovskite solar cells.

Printed electronics is a technology which is used for manufacturing flexible electronic devices dubbed as next-generation electronics such as wearable applications. To commercialize them, it is important to guarantee their electrical performance under various environmental conditions such as temperature and humidity. Moreover, flexible electronic devices usually undergo mechanical deformations such as bending and twisting, hence, it is necessary to observe the electrical performance of flexible devices under mechanical deformation considering both temperature and humidity. The effects of temperature and humidity on flexible printed electrodes, as an example of the simplest flexible electronics, under static deformation of bending and twisting are studied. Electrodes that do not deform are also strongly affected by temperature and humidity, and the increase in resistances of the electrodes with deformation is highest when twisting. The magnitude of static deformation does not affect the conductivity. The effect of line width is important for the twisting deformation. To commercialize printed electronics devices, the effects of temperature and humidity should be considered, with further consideration of the effects of mechanical deformation on the design of the devices.