Bulk heterojunction photovoltaic cells based on Merocyanine dye aggregates

基于低分子量有机化合物的溶液可加工体异质结（BHJ）器件的开发是一个新兴的研究领域，具有很高的成本效益的太阳能发电潜力。到目前为止，只有少数化合物可以确定为这种装置的合适电子供体组分。因此，为此目的探索新的高效分子半导体是一项具有挑战性但潜在回报的任务。我们最近观察到，作为非线性光学和光折变材料广泛应用的双极性merocyanine染料也表现出光伏活性，这促使我们探索这类传统着色剂在溶液可加工体异质结（BHJ）太阳能电池中的潜力。因此，我们在DFG优先项目“SPP 1355：有机光伏的基本过程”中最初提出的主要目标是研究双氰胺染料与富勒烯衍生物PCBM（[6,6]-苯基- c61 -丁酸甲酯）的混合物的光伏效率，双氰胺染料可以形成超分子聚合物。由于我们目前研究的双氰胺染料由于其较差的自聚集倾向和不利的溶解性而显示出相当低的功率转换效率，在即将到来的项目期间，我们将重点研究具有增强溶解度和自组装倾向的双氰胺染料，以充分解决超分子聚合的概念。此外，我们将把我们的概念扩展到三聚氰胺，这将导致分支的3d结构和网络。

Development of solution processable bulk heterojunction (BHJ) devices based on lowmolecular- weight organic compounds is an emerging research field with high potential for cost-effective generation of electricity from solar light. Until to date, only few compounds could be identified as suitable electron donor components for such devices. Thus, exploration of new efficient molecular semiconductors for this purpose is a challenging, but potentially rewarding, task. Our recent observation that dipolar merocyanine dyes, which are widely applied as nonlinear optical and photorefractive materials, also exhibit photovoltaic activities motivated us to explore the potential of this traditional class of colorants for solution processable bulk heterojunction (BHJ) solar cells. Thus, the major objective of our initial proposal within the DFG priority program “SPP 1355: Elementary Processes of Organic Photovoltaics” has been the investigation of photovoltaic efficiencies of blends of bismerocyanine dyes, which can form supramolecular polymers, with fullerene derivative PCBM ([6,6]-phenyl-C61-butyric acid methyl ester). As the bismerocyanine dyes that we have studied so far, show rather low power conversion efficiencies due to their poor selfaggregation propensity and unfavourable solubilities, in the forthcoming project period we will focus on bismerocyanine dyes with enhanced solubility and self-assembly propensity to adequately address the concept of supramolecular polymerization. Furthermore, we will extend our concept to trismerocyanines, which will lead to branched 3D-structures and networks.