期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：26
页码：7897-7902
DOI：10.1073/pnas.1508578112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThe development of system-independent and non-material-specific interfacial layers (IFLs) to facilitate efficient charge collection is of crucial importance for organic photovoltaic (OPV) cell performance. Here we report a broadly applicable IFL design strategy using solution-processed amorphous oxide semiconductors where their energetics can be tuned by varying the elemental composition without varying the surface chemistry. Based on the energetic requirements of specific organic active layers, these oxides can be readily designed with dialed-in energy levels. Using OPV solar cells as a test bed, we use a broad series of photoactive bulk heterojunction materials to demonstrate the effectiveness of these electronically tunable oxides for optimizing the performance of diverse OPV material sets. In diverse classes of organic optoelectronic devices, controlling charge injection, extraction, and blocking across organic semiconductor-inorganic electrode interfaces is crucial for enhancing quantum efficiency and output voltage. To this end, the strategy of inserting engineered interfacial layers (IFLs) between electrical contacts and organic semiconductors has significantly advanced organic light-emitting diode and organic thin film transistor performance. For organic photovoltaic (OPV) devices, an electronically flexible IFL design strategy to incrementally tune energy level matching between the inorganic electrode system and the organic photoactive components without varying the surface chemistry would permit OPV cells to adapt to ever-changing generations of photoactive materials. Here we report the implementation of chemically/environmentally robust, low-temperature solution-processed amorphous transparent semiconducting oxide alloys, In-Ga-O and Ga-Zn-Sn-O, as IFLs for inverted OPVs. Continuous variation of the IFL compositions tunes the conduction band minima over a broad range, affording optimized OPV power conversion efficiencies for multiple classes of organic active layer materials and establishing clear correlations between IFL/photoactive layer energetics and device performance.
