This is a sponsored post by KYOCERA Document Solutions Inc.
Kyocera Document Solutions has expanded its lineup of hole transport materials (HTMs) for perovskite solar cells, now offering SpiroOMeTAD and PTAA, and has begun research and development of novel HTMs.
Leveraging proprietary molecular design technologies for organic materials, it has developed and manufactured HTMs such as SpiroOMeTAD and PTAA using optimized production methods that ensure high quality and lot-to-lot consistency. These compounds have successfully completed pilot production at the kilogram scale and are now available for stable, cost-effective supply.
Technology Background
Founded in 1934, the company has long been a pioneer in innovative technologies. It develops, manufactures, and sells electronic photocopiers and printers equipped with amorphous silicon and organic photoconductor (OPC) drums. In addition to equipment manufacturing, it also develops and produces OPCs in-house—a core component of its devices.
Since the 1990s, the company has independently developed high-performance HTMs to support the advanced functionality of OPCs. Drawing on experience with organic low-molecular-weight compounds and polymers, such as aromatic tertiary amines used in OPCs, it has applied optimal manufacturing techniques to produce SpiroOMeTAD and PTAA with high quality and stability. These materials are now available in kilogram-scale quantities.
High quality and lot-to-lot consistency
HTMs are manufactured using optimized methods that ensure high quality and consistent performance across production lots. Evaluation of SpiroOMeTAD in perovskite solar cells with a regular (n-i-p) structure showed photoelectric conversion efficiencies of 23% or higher across all three lots, confirming minimal variation between batches.
Development of Novel HTMs
The company is actively developing monomer-based HTMs for regular (n-i-p) structures, as well as polymer-based HTMs and self-assembled monolayer (SAM) materials for inverted (p-i-n) structures. Recently, the company published research on PTAA derivatives for regular (n-i-p) structures.
The paper, titled Band Engineering of a PTAA Hole Transporting Layer in the n–i–p Architecture of MAPbI₃, was selected by the handling editor as one of the top 10% of papers published in Sustainable Energy & Fuels, based on exceptionally positive peer reviews and the editor’s assessment of its significance and impact. Band engineering of a PTAA hole transporting layer in the n–i–p architecture of MAPbI3-
In this study, they synthesized poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) derivatives with varied chemical structures, resulting in different HOMO energy levels. By introducing bulkier ethyl groups and modifying the triphenylamine moiety, the company achieved deeper HOMO levels and improved ionization potential. Devices using PTAA derivatives with a HOMO level of −5.39 eV demonstrated superior power conversion efficiency (PCE) compared to those with shallower HOMO levels.
Additionally, they confirmed that hole mobility was significantly enhanced by substituting parts of the biphenyl group with terphenyl, styryl, or bis-styryl groups. The company has not only conducted research on these novel compounds but also completed the development of scalable manufacturing processes, enabling supply at the kilogram scale.
Toward Mass Production and Sustainability
Preparations for mass production of HTMs for perovskite solar cells have been completed. Stable-quality prototypes are available upon request, and custom development tailored to specific customer needs is offered. Through continued innovation in materials, the company supports the widespread use of perovskite solar cells around the world and contributes to the realization of a sustainable society.