Here, we develop a method to prepare a dopant-free hole transporting material by blending an organic semiconductor and a conjugated polymer with 1,8-diiodooctane (DIO) additive. The normal-type solar cell based on the hole transporting material (HTM) blend with DIO + PCDTBT shows enhanced efficiency up to 18.0% compared to 14.7% for the device using the pristine small molecule. Incorporation of DIO results in increased crystallinity, while the conjugated polymer induces an intermolecular network for efficient charge transport with improved film morphology. Consequently, the HTM blend with DIO + PCDTBT shows a higher hole mobility and more efficient charge transfer at the perovskite/hole transporting layer interface compared with the pristine HTM. Furthermore, the solar cell introducing the HTM blend with DIO shows high mechanical and moisture stability; the compact and homogeneous film of high crystalline HTM shows more adhesive contact with perovskite and effectively prevents the penetration of moisture. The efficiency of the unencapsulated device using a small molecular HTM decreases to 60%, whereas the corresponding device with HTM blend maintains 80% performance after storage under 85% relative humidity and 85 °C.
Bibliographical noteFunding Information:
This work was supported from the Global Frontier R&D Program on Center for Multiscale Energy System ( 2015R1A1A1A05001115 ) and the KIST institutional programs ; this work was also supported by New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Knowledge Economy (MKE) ( 20163030013620 ).
© 2019 Elsevier B.V.
- Enhanced stability
- Hole transporting materials
- Perovskite solar cell
- Polymer blend
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering