Understanding Photo-conversion Processes in Biomimetic Photoelectrochemical Nanomaterials

PI：Choi Proposal Number：1134376基于太阳能光电转换为电能的太阳能电池存在相对较窄的光吸收和电池退化，这降低了器件的性能和寿命。在自然界中，光合作用解决了许多这样的问题。光合作用是一种生物介导的光电化学过程，将阳光转化为电子。自然光合作用已经完善了强大的分子机制，利用一系列发色团来增强光激发能量的收集，这些发色团通过自我再生来抵消光损伤的影响。通过用人工光系统模拟自然光合作用，可以更好地理解和改善光电化学电池目前的局限性。这项研究的总体目标是开发通用的设计规则，以构建具有更高的整体光转换效率和使用寿命的人造光系统。本研究试图通过生物分子纳米制造技术来模拟自然光合作用的光吸收/转化和自再生过程。具体地说，光颜料和量子线将通过可编程DNA分子识别技术进行可逆组装，形成能够全色吸收和系统修复的光电化学纳米结构。例如，基于DNA的单壁碳纳米管上选择性卟啉发色团的组装可以与G-四链体相互作用，从而促进纳米级的电荷转移。通过这种方法，将开发出各种能够模拟自然光系统的结构和功能的人工光转换纳米结构，并将利用超快泵浦-探测能量和电荷传输过程的测量来研究它们的光吸收和转换过程。这些数据将被分析以阐明光转化过程的热力学和动力学，并产生构建人工光合作用单元的设计规则。更广泛的影响拟议的活动将把研究工作与教育和推广活动结合起来，旨在提高公众对人工光合作用的理解。具体来说，将为高中生开发由普渡大学主办的向女孩介绍工程日和发现日的动手模块，研究成果也将在国家科学基金会资助的普渡纳米技术网站NanHUB上展示。通过普渡大学的女性工程和少数族裔工程项目，将招募女性和代表性不足的本科生参与这项研究。

PI: ChoiProposal Number: 1134376Solar cells based on photoelectrochemical conversion of sunlight to electricity suffer from relatively narrow light absorption and cell degradation, which reduces device performance and lifetime. In nature, photosynthesis has solved many of these problems. Photosynthesis is a biologically-mediated photoelectrochemical process for conversion of sunlight into electrons. Natural photosynthesis has perfected robust molecular machineries that enhance photo-excitation energy collection using an array of chromophores that counteract the effect of photo-damage via self-regeneration. The current limitations of photoelectrochemical cells can be better understood and potentially improved by mimicking natural photosynthesis with artificial photosystems. The overall goal of this research is to develop general design rules to build artificial photosystems with improved overall photo-conversion efficiency and service lifetime.This research seeks to mimic the photo-absorption/conversion and self-regeneration processes of natural photosynthesis with synthetic chromophore nanomaterials through biomolecular nanofabrication techniques. Specifically, photo-pigments and quantum wires will be reversibly assembled via programmable DNA molecular recognition techniques, forming photoelectrochemical nanostructures capable of panchromatic absorption and system repair. For example, DNA-based assembly of selective porphyrin chromophores on single-walled carbon nanotubes can interact with G-quadruplexes to facilitate charge transfer at the nanoscale. By this approach, a variety of synthetic photo-conversion nanostructures capable of mimicking the structure and function of natural photosystems will be developed, and their photo absorption and conversion processes will be studied using ultrafast pump-probe measurement of the energy and charge transport processes. This data will be analyzed to elucidate the thermodynamics and kinetics of photo-conversion processes, and generate design rules for constructing artificial photosynthetic units. Broader ImpactsThe proposed activities will couple the research efforts to educational and outreach activities designed to advance the public understanding of artificial photosynthesis. Specifically, hands-on modules for high-school students will be developed for Introduce a Girl to Engineering Day and Discovery Days hosted by Purdue University, and research outcomes will also be featured on nanoHUB, an NSF-funded, Purdue-based nanotechnology website. Female and underrepresented undergraduate students will be recruited for participation in the research through the Women in Engineering and Minority Engineering Programs at Purdue University.