CAS: Functionalization of Earth-Abundant, Molecular Group 4 Photosensitizers for Photochemical Applications

西弗吉尼亚大学化学系的Carsten Milsmann在化学部化学结构、动力学机制B（CSDM-B）计划和刺激竞争研究的既定计划（EPSCoR）的支持下，正在开发基于地球丰富的第4族元素的分子过渡金属光敏剂的新合成路线，这些光敏剂可用于光化学应用。&这项研究的目标是提供廉价且易于获得的光吸收分子，其具有太阳能燃料生产、极性溶液中的光吸收和光伏器件（例如，染料敏化太阳能电池）。从拟议的工作中获得的基本见解将扩大可用光敏剂的范围，并允许以更可持续的方式有针对性地设计捕光分子。拟议的研究将合成有机和无机化学的联合收割机元素与详细的物理调查相结合，从而为研究生和本科生的培训和教育提供了机会，这些学生对未来的科学家职业有着不同的兴趣。具有长寿命配体-金属电荷转移（LMCT）激发态的早期过渡金属光敏剂是一类新兴的无机发色团，其已在荧光、光子上转换和生物传感中找到应用。拟议的研究包括使用现有分子结构的合成后修饰，以（i）改善性能关键参数，如在极性溶剂中的稳定性和溶解性;（ii）将锚定基团固定在金属氧化物表面，从而促进光驱动空穴注入p型半导体;（iii）探讨分子对称性对第4族光敏剂光学性质的影响（例如，系统间交叉率、寿命和量子产率）并提供不对称复合物以促进在可见光激发时的定向电荷转移;以及（iv）探索第4族光敏剂设计的化学空间，并提供对早期过渡金属发色团基本设计原理的基本理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

WIth support from the Chemical Structure, Dynamics & Mechanisms-B (CSDM-B) Program of the Chemistry Division and the Established Program to Stimulate Competitive Research (EPSCoR), Carsten Milsmann of the Department of Chemistry at West Virginia University is developing new synthetic routes to molecular transition metal photosensitizers based on earth abundant group 4 elements that can be utilized in photochemical applications. The goal of this research is to provide cheap and readily available light-absorbing molecules with characteristics required for solar fuels production, photocatalysis in polar solutions, and the construction of photovoltaic devices (e.g., dye-sensitized solar cells). Fundamental insights gained from the proposed work will broaden the scope of available photosensitizers and allow the targeted design of light-harvesting molecules in a more sustainable way. The proposed studies combine elements of synthetic organic and inorganic chemistry with detailed photophysical investigations, allowing for training and education of graduate and undergraduate students with diverse interests for their future careers as scientists. Early transition metal photosensitizers with long-lived ligand-to-metal charge transfer (LMCT) excited states are an emerging class of inorganic chromophores that have found application in photocatalysis, photon upconversion, and biological sensing. The proposed research includes the use of postsynthetic modification of existing molecular architectures to (i) improve performance critical parameters such as stability and solubility in polar solvents; (ii) incorporate anchoring groups for immobilization on metal oxide surfaces, thereby facilitating light-driven hole injection into p-type semiconductors; (iii) explore the influence of molecular symmetry on the optical properties of group 4 photosensitizers (e.g. intersystem crossing rates, lifetimes, and quantum yields) and provide asymmetric complexes to facilitate directional charge transfer upon visible-light excitation; and (iv) explore the chemical space for group 4 photosensitizer design and provide fundamental understanding of the underlying design principles for early transition metal chromophores.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.