Plasmon-induced Triplet Energy Transfer (PITET) for Photon Upconversion

有了这个奖项，化学系的大分子，超分子和纳米化学项目正在支持加州滨江大学（UCR）的Ming Lee Tang博士研究等离子体系统的能量转移过程。 等离子体激元是指金属中松散束缚的电子的光诱导振荡。 这项研究对于催化，成像和能量转换应用非常重要。纳米级的微小金属颗粒因其在彩色玻璃窗中的美丽而在历史上受到珍视。彩色玻璃中鲜艳的色彩来自于金属纳米颗粒支持的等离子体激元对光的强烈吸收和散射。Tang博士的团队正在进行基础研究，旨在有效地将金属纳米颗粒中作为等离子体存储的能量转移到邻近的化学分子中。 该研究旨在提供机制，以防止系统通过光的快速散射或能量作为热量的耗散而产生不必要的能量损失。 这些进展对于开发金属纳米颗粒用于电池和太阳能电池中的预期应用至关重要。该团队设计和合成各种纳米材料架构。 等离子体激元紧密地限制在纳米级金属架构内，然后其特征在于调整系统以在光激活时执行有用的工作。 这项研究也有更广泛的影响，使公众参与内陆帝国计划在南加州。这项推广计划包括由本科生和研究生领导的当地小学和学前班的互动演示和科学活动。UCR的Ming Lee Tang博士的团队正在研究等离子体诱导的三重态能量转移。目标是利用金属纳米天线捕获的光进行光子上转换，这是一个将来自太阳等非相干源的低能光子转换为有用的高能光子的过程。在这项研究中，基于贵金属的新型光吸收纳米结构可以吸收近红外光子，从相邻的蒽和二萘嵌苯基发色团产生紫色光子发射。具体地，预期局部表面等离子体共振在1.5和1.8 eV之间调谐的银纳米棱镜和金纳米棒与发色团的最低激发三重态共振，从而使分子三重态光敏化穿过氧化物势垒。稳态光子上转换测量将用于量化等离子体激元诱导的三重态能量转移的效率。时间分辨光致发光和瞬态吸收测量提供了三重态能量转移的产率和速率的独立测量。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

With this award, the Macromolecular, Supramolecular, and Nanochemistry Program in the Chemistry Division is supporting Dr. Ming Lee Tang at the University of California Riverside (UCR) to study the energy transfer process of plasmonic systems. Plasmonics refers to light-induced oscillation of loosely bound electrons in metals. This research is important for catalysis, imaging, and energy conversion applications. Minuscule metal particles with dimensions on the order of nanometers have been treasured historically for their beauty in stained glass windows. The vivid colors in stained glass arise from the strong absorption and scattering of light due to plasmons supported by the metal nanoparticles. Dr. Tang’s team is conducting fundamental research that addresses that seeks to efficiently transfer the energy stored as plasmons in metal nanoparticles to neighboring chemical molecules. The research aims to provide mechanisms to prevent the system from unwanted energy loss through rapid scattering of light or dissipation of energy as heat. Such advances are essential for the development of metal nanoparticles for intended applications in photocatalysis and in solar cells. The team designs and synthesizes various nanomaterial architectures. Plasmons tightly confined within the nanoscale metal architectures are then characterized to tune the system to perform useful work upon light activation. This research also has broader impacts of engaging the general public in the Inland Empire program in Southern California. This outreach program includes interactive demonstrations and science activities at local elementary schools and pre-schools that are led by undergraduate and graduate students.Dr. Ming Lee Tang’s team at UCR is investigating plasmon-induced triplet energy transfer. The goal is to use light captured by metal nano-antennas for photon upconversion, a process of converting low energy photons from incoherent sources such as the sun to useful high energy photons. Novel light-absorbing nanostructures based on noble metals in this research can absorb near-infrared photons to produce violet photon emissions from neighboring anthracene- and perylene-based chromophores. Specifically, silver nanoprisms and gold nanorods with their localized surface plasmon resonance tuned between 1.5 and 1.8 eV are expected to be resonant with the lowest excited triplet states of the chromophores, so as to photosensitize the molecular triplet states across an oxide barrier. Steady-state photon upconversion measurements will be used to quantify the efficiency of plasmon-induced triplet energy transfer. Time resolved photoluminescence and transient absorption measurements provide independent measurements of the yield and rate of the triplet energy transfer.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.