Sasitharan Kezia, Frisch Johannes, Kuliček Jaroslav, Iraqi Ahmed, Lidzey David G, Bär Marcus, Rezek Bohuslav, Foster Jonathan A
Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, S3 7HF, UK.
Centre for Advanced Photovoltaics, Faculty of Electrical Engineering, Czech Technical University in Prague, 16000, Prague, Czech Republic.
Sci Rep. 2024 Nov 28;14(1):29559. doi: 10.1038/s41598-024-80007-y.
Metal-organic framework nanosheets (MONs) have proved themselves to be useful additives for enhancing the performance of a variety of thin film solar cell devices. However, to date only isolated examples have been reported. In this work we take advantage of the modular structure of MONs in order to resolve the effect of their different structural and optoelectronic features on the performance of organic photovoltaic (OPV) devices. Three different MONs were synthesized using different combinations of two porphyrin-based ligands meso-tetracarboxyphenyl porphyrin (TCPP) or tetrapyridyl-porphyrin (TPyP) with either zinc and/or copper ions and the effect of their addition to polythiophene-fullerene (P3HT-PCBM) OPV devices was investigated. The power conversion efficiency (PCE) of devices was found to approximately double with the addition of MONs of Zn(ZnTCPP) -4.7% PCE, 10.45 mA/cm short-circuit current density (J), 0.69 open-circuit voltage (V), 64.20% fill-factor (FF), but was unchanged with the addition of Cu(ZnTPyP) (2.6% PCE, 3.68 mA/cm J, 0.59 V, 46.27% FF) and halved upon the addition of Cu(CuTCPP) (1.24% PCE, 6.72 mA/cm J, 0.59 V, 56.24% FF) compared to devices without nanosheets (2.6% PCE, 6.61 mA/cm J, 0.58 V, 56.64% FF). Our analysis indicates that there are three different mechanisms by which MONs can influence the photoactive layer - light absorption, energy level alignment, and morphological changes. Analysis of external quantum efficiency, UV-vis and photoelectron spectroscopy data found that MONs have similar effects on light absorption and energy level alignment. However, atomic force and Raman microscopy studies revealed that the nanosheet thickness and lateral size are crucial parameters in enabling the MONs to act as beneficial additives resulting in an improvement of the OPV device performance. We anticipate this study will aid in the design of MONs and other 2D materials for future use in other light harvesting and emitting devices.
金属有机框架纳米片（MONs）已证明自身是用于提高各种薄膜太阳能电池器件性能的有用添加剂。然而，迄今为止仅报道了个别实例。在这项工作中，我们利用MONs的模块化结构来解析其不同的结构和光电特性对有机光伏（OPV）器件性能的影响。使用两种基于卟啉的配体——中位四羧基苯基卟啉（TCPP）或四吡啶基卟啉（TPyP）与锌离子和/或铜离子的不同组合合成了三种不同的MONs，并研究了将它们添加到聚噻吩 - 富勒烯（P3HT - PCBM）OPV器件中的效果。发现添加Zn（ZnTCPP）的MONs后器件的功率转换效率（PCE）大约翻倍——PCE为4.7%，短路电流密度（J）为10.45 mA/cm²，开路电压（V）为0.69，填充因子（FF）为64.20%，但添加Cu（ZnTPyP）（PCE为2.6%，J为3.68 mA/cm²，V为0.59，FF为46.27%）后效率不变，而添加Cu（CuTCPP）（PCE为1.24%，J为6.72 mA/cm²，V为0.59，FF为56.24%）后与未添加纳米片的器件（PCE为2.6%，J为6.61 mA/cm²，V为0.58，FF为56.64%）相比效率减半。我们的分析表明，MONs可通过三种不同机制影响光活性层——光吸收、能级排列和形态变化。对外部量子效率、紫外 - 可见光谱和光电子能谱数据的分析发现，MONs对光吸收和能级排列有相似的影响。然而，原子力显微镜和拉曼显微镜研究表明，纳米片的厚度和横向尺寸是使MONs能够作为有益添加剂从而提高OPV器件性能的关键参数。我们预计这项研究将有助于MONs和其他二维材料的设计，以便未来用于其他光捕获和发光器件。
