Seongkyun Kim , Taeyeop Kim , Jaehyun Sung , Yongjun Kim , Dongwoo Lee and Seunghyun BaikMaterials Horizons
Thermal rectification is an asymmetric heat transport phenomenon where thermal conductance changes depending on the temperature gradient direction. The experimentally reported efficiency of thermal rectification materials and devices, which are applicable for a wide range of temperatures, is relatively low. Here we report a giant thermal rectification efficiency of 218% by maximizing asymmetry in …
C. MUHAMMED AJMAL, SEOKJAE CHA, WONJOON KIM, K. P. FASEELA, HEEJUN YANG, AND SEUNGHYUN BAIKScience Advances
The dependence of the electrical resistance on materials’ geometry determines the performance of conductive nanocomposites. Here, we report the invariable resistance of a conductive nanocomposite over 30% strain. This is enabled by the in situ–generated hierarchically structured silver nanosatellite particles, realizing a short interparticle distance (4.37 nm) in a stretchable silicone rubber matr…
K. P. Faseela, C. Muhammed Ajmal, Seokjae Cha, Seunghyun BaikAdvanced Functional Materials
Copper (Cu) is an attractive low-cost alternative to silver or gold. However, it is susceptible to oxidation in air. Here, facile in situ regeneration of oxidized Cu flakes (CuFLs) for the synthesis of highly conductive non-oxidized nanocomposites is reported. The oxidized CuFLs are regenerated into non-oxidized CuFLs and Cu nanosatellite (CuNS) particles by formic acid-aided in situ etching and r…
Shabas Ahammed Abdul Jaleel, Taehun Kim, Seunghyun BaikAdvanced Materials
Phase-change materials (PCMs) have received considerable attention to take advantage of both pad-type and grease-type thermal interface materials (TIMs). However, the critical drawbacks of leaking, non-recyclability, and low thermal conductivity (κ) hinder industrial applications of PCM TIMs. Here, leakage-free healable PCM TIMs with extraordinarily high κ and low total thermal resistance (Rt) are…
Recent advance in flexible electronics demands development of flexible energy sources. Of particular interests are flexible dye-sensitized solar cells (DSCs). However, a brittle nature of TiO2 materials is one of hurdles to realize flexible DSCs. Here we synthesized flexible photoanodes of TiO2 particles and single-walled carbon nanotubes (SWNTs). Metallic SWNTs provided a greater photovoltaic conversion efficiency than semiconducting SWNTs due to the more efficient electron transport. The metallic SWNTs also constructed effective mechanical network among TiO2 particles providing flexibility and durability. The photoanode was transferred on an indium tin oxide (ITO)-coated polyethylene terephthalate film and characterized for front-illuminated DSCs under the AM 1.5 simulated sunlight. There was only a small decrease in photovoltaic conversion efficiency with bending which was primarily caused by cracking of the ITO layer. Due to this limitation, the TiO2–metallic SWNT photoanode was transferred on a Ti foil and went through up to 1000 bending cycles. The cycled photoanode was assembled for back-illuminated DSCs due to the non-transparent Ti foil. There was no decrease in photovoltaic conversion efficiency even after 1000 bending cycles demonstrating excellent flexibility and durability.
