Institute for Materials Chemistry and Engineering & IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
College of Physical Science and Technology, Yangzhou University, Jiangsu, 225009, P. R. China.
Nat Commun. 2023 Jun 9;14(1):3394. doi: 10.1038/s41467-023-39127-8.
To alleviate the energy and environmental crisis, in the last decades, energy harvesting by utilizing optical control has emerged as a promising solution. Here we report a polar crystal that exhibits photoenergy conversion and energy storage upon light irradiation. The polar crystal consists of dinuclear [CoGa] molecules, which are oriented in a uniform direction inside the crystal lattice. Irradiation with green light induces a directional intramolecular electron transfer from the ligand to a low-spin Co centre, and the resultant light-induced high-spin Co excited state is trapped at low temperature, realizing energy storage. Additionally, electric current release is observed during relaxation from the trapped light-induced metastable state to the ground state, because the intramolecular electron transfer in the relaxation process is accompanied with macroscopic polarization switching at the single-crystal level. It demonstrates that energy storage and conversion to electrical energy is realized in the [CoGa] crystals, which is different from typical polar pyroelectric compounds that exhibit the conversion of thermal energy into electricity.
为缓解能源和环境危机，在过去几十年中，利用光学控制进行能量收集已成为一种很有前途的解决方案。在这里，我们报告了一种在受到光辐照时表现出光电能量转换和储能的极性晶体。该极性晶体由双核[CoGa]分子组成，这些分子在晶格内定向排列。绿光照射诱导从配体到低自旋 Co 中心的定向分子内电子转移，所得光致高自旋 Co 激发态在低温下被捕获，实现能量存储。此外，在从捕获的光致亚稳态到基态的弛豫过程中观察到电流释放，因为在弛豫过程中分子内电子转移伴随着单晶水平上的宏观极化翻转。这表明能量存储和转换为电能是在[CoGa]晶体中实现的，这与典型的极性热释电化合物不同，后者表现为热能转化为电能。
