Chen Meng, Wang Yingxin, Ma Wenle, Huang Yi, Zhao Ziran
National Engineering Laboratory for Dangerous Articles and Explosives Detection Technologies, Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
National Institute for Advanced Materials, Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Key Laboratory of Functional Polymer Materials Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Materials Science and Engineering, Nankai University, Tianjin 300071, China.
ACS Appl Mater Interfaces. 2020 Jun 24;12(25):28510-28519. doi: 10.1021/acsami.0c05833. Epub 2020 Jun 12.
The photothermoelectric (PTE) effect can effectively convert light into electricity through photothermal and thermoelectric processes and has great potential applications in light energy harvesting and bandgap-independent photodetection. It is particularly applicable for the terahertz (THz) range featuring low photon energy but has not been well established due to lack of high-performance PTE materials in this range. Three-dimensional microporous graphene (3DMG) foam possesses ultrahigh THz absorptivity and outstanding photothermal conversion and can serve as a promising candidate. Here, enhancement of the THz PTE response of 3DMG foam by fine-tuning its thermoelectric properties using the ionic liquid electric double layer (EDL) technique was demonstrated. Continuous and reversible control of the Seebeck coefficient of 3DMG highlights the effectiveness of EDL gating in manipulating the electronic structures of such bulk and porous material. An approximate 1 order of magnitude enhancement in the Seebeck coefficient as well as the PTE responsivity was observed. In addition, a double-cell 3DMG EDL device with a p-n junction like channel configuration enabled further improvement of the photoresponse. This work opens a new avenue to optimize the PTE performance of 2D nanosheet-assembled 3D porous materials for highly efficient energy harvesting and detection of THz radiation.
光热发电（PTE）效应可通过光热和热电过程有效地将光转化为电，在光能收集和与带隙无关的光探测方面具有巨大的潜在应用价值。它特别适用于光子能量较低的太赫兹（THz）波段，但由于该波段缺乏高性能的PTE材料，其研究尚未成熟。三维微孔石墨烯（3DMG）泡沫具有超高的太赫兹吸收率和出色的光热转换性能，可作为一种很有前景的候选材料。在此，通过使用离子液体双电层（EDL）技术微调其热电性能，证明了3DMG泡沫的太赫兹PTE响应得到增强。对3DMG的塞贝克系数进行连续且可逆的控制，突出了EDL门控在操纵此类块状和多孔材料电子结构方面的有效性。观察到塞贝克系数以及PTE响应率提高了约1个数量级。此外，具有类似p-n结通道结构的双电池3DMG EDL器件使光响应得到进一步改善。这项工作为优化二维纳米片组装的三维多孔材料的PTE性能开辟了一条新途径，以实现高效的能量收集和太赫兹辐射探测。
