Room-temperature hyperpolarization of polycrystalline samples with optically polarized triplet electrons: pentacene or nitrogen-vacancy center in diamond?
Room-temperature hyperpolarization of polycrystalline samples with optically polarized triplet electrons: pentacene or nitrogen-vacancy center in diamond?
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DOI：
10.5194/mr-2-33-2021
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Negoro M
中科院分区：
文献类型：
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作者：
Miyanishi K;Segawa TF;Takeda K;Ohki I;Onoda S;Ohshima T;Abe H;Takashima H;Takeuchi S;Shames AI;Morita K;Wang Y;So FT;Terada D;Igarashi R;Kagawa A;Kitagawa M;Mizuochi N;Shirakawa M;Negoro M
我们证明了室温C超极化的动态核极化（DNP）使用光学极化三重态电子自旋在两个多晶系统：并五苯掺杂的[羧基-C]苯甲酸和含有氮空位（NV）中心的微金刚石。对于这两种样品，使用积分固体效应（伊势）在350-400 mT的磁场中对C自旋系统进行自旋分析。在苯甲酸样品中，C自旋极化通过直接电子到C极化转移而增强高达0.12%，而不进行动态H极化，然后进行交叉极化。此外，伊势已成功应用于将微金刚石样品中天然丰富的C自旋降低至0.01%。为了表征C极化的建立，我们讨论了电子和C自旋之间的直接极化转移以及自旋扩散的效率，检查各种参数，这是有益的或有害的成功的批量动态C极化。
We demonstrate room-temperature C hyperpolarization by dynamic nuclear polarization (DNP) using optically polarized triplet electron spins in two polycrystalline systems: pentacene-doped [carboxyl-C] benzoic acid and microdiamonds containing nitrogen-vacancy (NV) centers. For both samples, the integrated solid effect (ISE) is used to polarize the C spin system in magnetic fields of 350–400 mT. In the benzoic acid sample, the C spin polarization is enhanced by up to 0.12 % through direct electron-to-C polarization transfer without performing dynamic H polarization followed by cross-polarization. In addition, the ISE has been successfully applied to polarize naturally abundant C spins in a microdiamond sample to 0.01 %. To characterize the buildup of the C polarization, we discuss the efficiencies of direct polarization transfer between the electron and C spins as well as that of spin diffusion, examining various parameters which are beneficial or detrimental for successful bulk dynamic C polarization.