https://scholar.dgist.ac.kr/handle/20.500.11750/47658 2026-10-13T23:51:02Z https://scholar.dgist.ac.kr/handle/20.500.11750/60870 Title: Self-poled and poling-free efficient piezoelectric nanogenerators for power generation and self-powered applications Author(s): Kumar, Naveen; Kaja, Kushal Ruthvik; Panda Swati; Hajra Sugato; Belal, Mohamed Ahmed; Bhosale, Premkumar Sharad; Khanapuram, Uday Kumar; Rajaboina, Rakesh Kumar; Keum, Hohyun; Lee, Kyoungtae; Kim, Hoe Joon Abstract: Piezoelectric nanogenerators (PENGs) have emerged as promising energy harvesters capable of converting waste mechanical energy into usable electrical power for self-powered electronic applications. Traditionally, PENGs require an external poling process to align ferroelectric dipoles and achieve efficient operation. However, reliance on high-voltage poling, time-consuming processing, and potential material degradation limits the scalability and practicality of conventional PENGs. Recent research has therefore focused on developing self-poled, polingfree PENGs that offer intrinsic polarization, enhanced stability, and simplified fabrication without external treatments. This review summarizes the fundamental working principles of PENGs and the effect of polarization on their performance. Then, an in-depth discussion of the concept and comparison between the self-poling and poling-free mechanisms is provided. Recent advances in self-poled or poling-free PENGs, material innovations, including polymers, ceramics, and composites, as well as device engineering strategies that enable efficient energy conversion without external poling, are also demonstrated. The review concludes with significant challenges, including material durability, large-scale fabrication, and integration into complex systems, as well as future research prospects for developing next-generation self-powered technology. By integrating current advances and highlighting key obstacles, the review attempts to offer valuable insights into the future development of efficient, scalable, and environmentally sustainable poling-free PENGs. To the best of our knowledge, this is the first comprehensive review of self-poled and poling-free PENGs, focusing on underlying mechanisms, material fabrication methods, and emerging applications. 2026-05-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60118 Title: A Spectral-Efficient Low-Power NRZ/PAM-4 Dual-Mode Wireline Transmitter for Multidrop Interfaces Author(s): Kim, Donggeon; Gharibdoust, Kiarash; Tajalli, Armin; Lee, Kyoungtae; Kim, Gain Abstract: This paper presents a reconfigurable and energy-efficient digital spectrum shaping signaling (DSSS) for multidrop interfaces, where the output spectrum of the transmitted data is shaped using the 2-times repetitive block transmission to avoid frequency notches in the multidrop channel, thereby achieving a data rate up to 4x the first channel notch frequency. In conventional wireline transceivers (TRX), compensating for frequency notches requires a large number of decision feedback equalizer (DFE) taps at the receiver, resulting in significant area and power overhead. In contrast, the proposed DSSS architecture supports spectrum-efficient reconfigurable dual-mode NRZ/PAM4, reducing required equalization efforts and improving energy efficiency. The proposed scheme and its transmitter (TX) were first validated through event-driven behavioral simulations using XMODEL and verified with equipment-based measurements. Post-layout simulation results in 28nm CMOS process demonstrated 4 Gb/s data rate communicating over a channel having its first > 30 dB notch at 1 GHz, with a 235mV vertical eye opening and a TX energy efficiency of 0.39 pJ/b at 0.8V supply. 2025-08-07T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59341 Title: Triboelectric energy harvesting from rice paper/PDMS under extreme humidity environments Author(s): Panda, Swati; Hajra, Sugato; Bhosale, Premkumar Sharad; Belal, Mohamed Ahmed; Kaja, Kushal Ruthvik; Kim, Hoe Joon; Lee, Kyoungtae Abstract: A flexible and eco-friendly triboelectric nanogenerator (TENG) based on rice paper (RP) and Polydimethylsiloxane (PDMS) was fabricated for efficient energy harvesting. The device produced a high output of 305 V, 2.6 μA current, and a charge of 29 nC. Various biomechanical energies from different body motions were harvested using the RP-PDMS TENG device. Typically, the TENG output depleted under extreme environmental conditions. Hence, the TENG device was packed using a waste polythene pouch, which enabled greater stability of electrical voltage under harsh humidity conditions (>85 % RH). This packed TENG shows great promise for self-powered wearable devices and environmentally robust energy harvesting applications. 2026-02-28T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58302 Title: A 0.05 mm3 diode-based single charged-particle real-time radiation detector for electron radiotherapy Author(s): Lee, Kyoungtae; Lall, Rahul; Maharbiz, Michel M.; Anwar, Mekhail Abstract: Real-time radiation monitoring at the single-particle level is an unmet need for electron radiotherapy, especially for dose deposition to targets in motion or critical OARs. We have developed a first-in-class CMOS-based 0.05 mm3 single electron sensitive detector. The chiplet integrates all the requisite electronics. The functionality of the system is verified under 6 and 9 MeV clinical electron beams. Percentage depth vs. pulse-width curves for 6 and 9 MeV beams are measured and verified using Monte-Carlo simulations. The proposed system has the potential to enhance the electron radiotherapy quality and safety, providing real-time dosimetry from multiple sites simultaneously. © 2025 The Author(s) 2025-03-31T15:00:00Z