SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education , Southeast University , Nanjing 210096 , P. R. China.
ACS Appl Mater Interfaces. 2018 May 16;10(19):16666-16673. doi: 10.1021/acsami.8b04455. Epub 2018 May 7.
Bidirectional photoswitching of molecular materials under ambient condition is of significant importance. Herein, we present for the first time that a core-shell UCNP-SCO nanosphere (UCNP = upconversion nanophosphor, SCO = spin crossover), which was composed of a UCNP core (NaYF: 20 mol % Yb, 1 mol % Er) and an SCO iron(II) shell ([Fe(HBpz)(bipy-COOH)], HBpz = dihydrobis(1-pyrazolyl)borate, bipy-COOH = 4,4'-dicarboxy-2,2'-bipyridine), can be reversibly photoswitched between the high-spin and low-spin states at room temperature in the solid state, via alternating irradiation with near-infrared (λ = 980 nm) and ultraviolet (λ = 310 nm) light. What's more, this reversible spin-state switching was accompanied by a variation of fluorescent spectrum and dielectric constants. The strategy here, that is, integrating the SCO iron(II) complex into a UCNP-SCO nanosphere for molecular photoswitching, may open a new area in the development of photocontrolled molecular devices.
在环境条件下实现分子材料的双向光致变色具有重要意义。在此，我们首次提出，核壳型上转换纳米球（UCNP = 上转换纳米荧光粉，SCO = 自旋交叉），由 UCNP 核（NaYF:20mol%Yb,1mol%Er）和 SCO 铁（II）壳([Fe(HBpz)(bipy-COOH)]，HBpz = 二氢双（1-吡唑基）硼酸盐，bipy-COOH = 4,4'-二羧酸-2,2'-联吡啶)组成，可在室温下通过交替辐照近红外（λ = 980nm）和紫外（λ = 310nm）光，在固态中可逆地在高自旋态和低自旋态之间切换。更重要的是，这种可逆的自旋态转换伴随着荧光光谱和介电常数的变化。在此，将 SCO 铁（II）配合物整合到 UCNP-SCO 纳米球中用于分子光开关的策略，可能为光控分子器件的发展开辟新的领域。
