Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-018-9572-4 Signifcance of encapsulating organic temperature sensors through spatial atmospheric atomic layer deposition for protection against humidity Mohammad Mutee ur Rehman 1  · Muhammad Muqeet Rehman 2  · Memoon Sajid 1,3  · Jae‑Wook Lee 1  · Kyoung Hoan Na 4  · Jeong Beom Ko 5  · Kyung Hyun Choi 1 Received: 30 March 2018 / Accepted: 27 June 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract Printed organic sensors are of signifcant importance owing to their simplicity, low cost, easy fabrication and solution pro- cessability. However, organic sensors often face the problem of performance degradation when exposed to ambient environ- ment therefore, the efect of humidity needs to be studied for prolonging the lifetime of organic sensors. In this study, we propose atomically thin and highly reliable encapsulation layer on the surface of an organic functional material to enhance its lifetime as a temperature sensing unit. Our organic temperature sensor is based on a conductive and uniform IDT pattern deposited on a glass substrate through advanced printing technology of reverse ofset. Thin flm of PEDOT:PSS is used as the temperature sensitive functional layer deposited through electrohydrodynamic atomization while the organic thin flm was encapsulated with aluminum oxide (Al 2 O 3 ) through spatial atmospheric atomic layer deposition system (SAALD). The temperature range of the developed sensors was from 25 to 90 °C with relative humidity reaching up to 75% RH. The obtained results exhibited that Al 2 O 3 encapsulation deposited through SAALD signifcantly enhanced the linearity, repeatability, endurance (50 cycles), retention (1 month) and lifetime of organic temperature sensor as compared to the non-encapsulated sensor. The performance degradation mechanism of non-encapsulated sensor due to humid environment has been discussed in detail. This study contributes an important step forward for preserving the performance and elongating the lifetime of organic electronic devices through a single atomically thin encapsulation. 1 Introduction Organic polymers have gained signifcant importance in recent years owing to their promising properties of low cost, conductivity, fexibility, scalability, light weight, solution processability, and compatibility with several fabrication techniques [1–5]. Organic polymers seem to be the ultimate solution to various medical, industrial and environmental problems owing to their in-built electrical, mechanical, opti- cal and chemical characteristics [6]. Numerous electronic devices have already been reported to date in which organic polymers act as the functional material for diverse applica- tions such as OLEDs [7], sensors [8], transistors [9], solar cells [10], memristors [11–13], batteries [14], and superca- pacitors [15] etc. However, one major disadvantage restrict- ing these organic polymer devices from commercialization at a large scale is degradation in their device performance due to exposure to ambient environment. Humidity is the main factor that deteriorates the perfor- mance of organic devices hence, reducing their lifetime. Mohammad Mutee ur Rehman and Muhammad Muqeet Rehman have contributed equally to this work. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10854-018-9572-4) contains supplementary material, which is available to authorized users. * Jeong Beom Ko no1kori@kitech.re.kr * Kyung Hyun Choi amm@jejunu.ac.kr 1 Department of Mechatronics Engineering, Jeju National University, Jeju City, Republic of Korea 2 Faculty of Electrical Engineering, GIK Institute of Engineering Sciences & Technology, Topi, KPK, Pakistan 3 Department of Electrical Engineering, COMSATS Institute of Information Technology, Islamabad, Pakistan 4 Department of Engineering, Dankook University, Yongin, Republic of Korea 5 Korea Institute of Industrial Technology, Gangneung, Republic of Korea