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Soft Science

Na et al. Soft Sci. 2026, 6, 25 DOI:10.20517/ss.2025.122

Recent advances in zero-power optoelectronic
synapses with potential for wearable neuromorphic
platforms

Myeonghyeon Na , Jinyeong Park , Kyoseung Sim 1,2,*
1,#
1,#
Keywords:
Zero-power, optoelectronic
synapse, wearable systems

Citation: Na, M.; Park, J.;
Sim, K. Recent advances in
zero-power optoelectronic
synapses with potential for
wearable neuromorphic
platforms. Soft Sci. 2026, 6,
25.
https://dx.doi.org/10.20517
/ss.2025.122

Received: 29 Nov 2025
First Decision: 26 Dec
2025
Revised: 9 Jan 2026
Accepted: 21 Jan 2026 Abstract
Published: 3 Apr 2026
Zero-power optoelectronic synapses, defined as optoelectronic synaptic devices operating
Academic Editors: without external electrical bias, are emerging as core components for energy-efficient
Kuniharu Takei, Xingcan intelligent wearable neuromorphic platforms. Wearable neuromorphic systems require
Huang
Copy Editor: continuous, autonomous operation under strict constraints on power consumption,
Xing-Yue Zhang mechanical compliance, and thermal safety, making conventional electrically biased
Production Editor: synaptic devices impractical for long-term body-interfaced use. By harvesting light to drive
Xing-Yue Zhang
synaptic modulation without external bias, these devices integrate sensing, learning,
memory, and processing within a single self-sustained element. This light-driven operation
is therefore particularly well suited for wearable platforms, where energy availability is
limited and frequent recharging or battery replacement is undesirable. This review
summarizes recent progress in zero-power optoelectronic synapses based on three
representative mechanisms: Schottky junctions, heterojunctions, and photothermoelectric
effect. Despite notable progress, several fundamental challenges continue to limit practical
deployment. These include limited light utilization, insufficient bidirectional weight
modulation, instability and variability, mechanical incompatibility, and lack of system-level
integration, which remain major hurdles. These limitations hinder the reliable operation,

1 Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
2 X-Dynamic Research Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
# Authors contributed equally.

* Correspondence to: Prof. Kyoseung Sim, Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan
44919, Republic of Korea. E-mail: kyos@unist.ac.kr

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