Zebra-inspired stretchable, biodegradable radiation modulator for all-day sustainable energy harvesters

Abstract

Recent advances in passive radiative cooling systems describe a variety of strategies to enhance cooling efficiency, while the integration of such technology with a bioinspired design using biodegradable materials can offer a research opportunity to generate energy in a sustainable manner, favorable for the temperature/climate system of the planet. Here, we introduce stretchable and ecoresorbable radiative cooling/heating systems engineered with zebra stripe–like patterns that enable the generation of a large in-plane temperature gradient for thermoelectric generation. A comprehensive study of materials with theoretical evaluations validates the ability to accomplish the target performances even under external mechanical strains, while all systems eventually disappear under physiological conditions. Use of the zebra print for selective radiative heating demonstrates an unexpected level of temperature difference compared to use of radiative cooling emitters alone, which enables producing energy through resorbable silicon-based thermoelectric devices. The overall result suggests the potential of scalable, ecofriendly renewable energy systems.

Micropatterned Elastomeric Composites for Encapsulation of Transient Electronics

“…The synthesis of PLCL followed our previous work with minor modifications. 43 In a dried glass ampule equipped with a magnetic stirring bar, predetermined amounts of ε-caprolactone (ε-CL, Alfa Aesar, USA; 500 mmol), L-lactide (LA, Medichem, South Korea; 500 mmol), stannous octoate (Sn(Oct) 2 , Alfa Aesar, USA; 5 mmol), and 1dodecanol (Alfa Aesar, USA; 0.05 mmol) were added. The ampule was purged three times with N 2 at 90 °C and sealed under a vacuum before being heated in an oil bath at 150 °C.…”

Recent progress in thermal management for flexible/wearable devices

“…Lee et al assembled a skin-like, stretchable, and dual-mode thermo-haptic device for a virtual reality experience [138] . The conceptual process of the skin-like thermo-haptic (STH) device is shown in Figure 6E.…”

“…Copyright 2017, Elsevier; (E) dual-mode operation of skin-like thermo-haptic device by changing current flow; (F) IR images of device cooling/heating mode mounted on the palm. Reproduced with permission [138] . Copyright 2020, Wiley-VCH GmbH; (G) conceptual view of zebra-inspired radiative cooling membrane with TE generator; (H) energy flow of energy-harvesting system and photograph of n-and p-type Si NM TE generator array.…”

Mechanically-Guided 3D Assembly for Architected Flexible Electronics

“…In this work, a buckled bistable serpentine structure equipped with a proof mass was also manufactured, featuring the generation of electrical powers across a wide range of frequencies, spanning 2 orders of magnitude (from 5 to 500 Hz). Integrating thin-film thermoelectric materials (i.e., doped Si) with compliant 3D architectures allowed for efficient thermal impedance matching and increased power conversion efficiencies. ,, For example, a 3D flexible helical array (i.e., an 8 × 8 helical coils array) was prepared for thermoelectric energy harvesting (Figure d) . In particular, the open-circuit voltage generated by this thermoelectric harvester reached 51.3 mV subjected to a temperature difference of only 19 K, and the measured output power was 2 nW.…”

“…Aside from the vibrational energies, photogenerated energies (often in form of solar energies) are also ubiquitous in nature. The existing devices for photoenergy harvesting or conversion are mostly in planar configurations, such as solar cells, ,, photoelectrochemical water splitting (PEC) cells, − devices for artificial photosynthesis, photocatalytic CO 2 reductions cells, , and so on. Due to the angle-dependent optical properties of 2D structures (e.g., absorption, reflection, transmittance, scattering, and other forms of optical interactions), planar devices are not able to take full use of solar energies (e.g., shadowing caused by low incident angles of lights).…”