Hypothetical Efficiency of Electrical to Mechanical Energy Transfer during Individual Stochastic Molecular Switching Events
Hypothetical Efficiency of Electrical to Mechanical Energy Transfer during Individual Stochastic Molecular Switching Events
复制标题
单个随机分子切换事件期间电能到机械能转移的假设效率
DOI：
10.1021/acsnano.0c04082
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发表时间：
2020
期刊：
影响因子：
17.1
通讯作者：
Sykes, E. Charles
中科院分区：
文献类型：
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作者：
Larson, Amanda M.;Balema, Tedros A.;Zahl, Percy;Schilling, Alex C.;Stacchiola, Dario J.;Sykes, E. Charles
现在文献中有许多单分子转子、马达和开关的例子，当它们被光子、电子或化学反应驱动时，表现出明确的运动。作为使用这些单分子器件执行有用功能的一步，必须了解它们如何与环境相互作用，并量化它们对环境做功的能力。使用单分子旋转开关，我们研究了通过电子隧穿传递的电能到机械运动的转移，并使用非接触式q+原子力显微镜测量开关所经历的力。作用光谱表明，该分子开关具有两个稳定态，在100 mV偏压下，通过单电子非弹性隧穿过程（对应于16 zJ的能量输入）在两个稳定态之间共振激发.虽然电诱导的开关事件是随机的，并且在悬臂上没有净功，但是通过测量分子开关和AFM悬臂之间的力，我们可以推导出开关在单个开关事件期间可以执行的最大假设功，其为1.55 meV，等于8.9 zJ，这转化为每个单独的非弹性隧穿电子感应切换事件的假设效率为1055%。当考虑总电能输入时，由于主导隧穿电流的弹性隧穿事件，这下降到1 × 10-7%。然而，这种方法构成了量化和比较分子机械装置的能量输入和输出的一般方法。
There are now many examples of single molecule rotors, motors, and switches in the literature that, when driven by photons, electrons, or chemical reactions, exhibit well-defined motions. As a step toward using these single molecule devices to perform useful functions, one must understand how they interact with their environment and quantify their ability to perform work on it. Using a single molecule rotary switch, we examine the transfer of electrical energy, deliveredviaelectron tunneling, to mechanical motion and measure the forces the switch experiences with a noncontact q-plus atomic force microscope. Action spectra reveal that the molecular switch has two stable states and can be excited resonantly between them at a bias of 100 mVviaa one-electron inelastic tunneling process which corresponds to an energy input of 16 zJ. While the electrically induced switching events are stochastic and no net work is done on the cantilever, by measuring the forces between the molecular switch and the AFM cantilever, we can derive the maximum hypothetical work the switch could perform during a single switching event, which is ∼55 meV, equal to 8.9 zJ, which translates to a hypothetical efficiency of ∼55% per individual inelastic tunneling electron-induced switching event. When considering the total electrical energy input, this drops to 1 × 10–7% due to elastic tunneling events that dominate the tunneling current. However, this approach constitutes a general method for quantifying and comparing the energy input and output of molecular-mechanical devices.