Indoor organic photovoltaics (OPVs) show immense potential as a reliable energy harvester for powering emerging Internet of Things devices because of their unique optoelectrical properties. The extremely low number of charge carriers under indoor lighting conditions in comparison to 1-sun conditions necessitates different techniques to optimize the performance of indoor OPVs. In this study, an indium tin oxide (ITO) surface was modified using a water-soluble β-cyclodextrin–polyacryloyl hydrazide (CD–PAH). The abundant amine functional groups on the polyacryloyl hydrazide arms induce a vacuum-level shift owing to their excellent electron-withdrawing ability. Consequently, the work function (WF) of ITO decreased from 4.5 to 4.1 eV, providing a suitable energy-level alignment between ITO and the photoactive layer. The photovoltaic performance of inverted poly(3-hexylthiophene):indene-C60 bisadduct-based OPVs with the surface-treated ITO was evaluated under various lighting conditions. The average power conversion efficiency of the optimized OPV increased substantially from 1.2 ± 0.1% to 3.5 ± 0.1% under 1 sun illumination and 2.4 ± 0.2% to 8.1 ± 0.4% under light-emitting diode illumination. This remarkable performance improvement can be attributed to the excellent transmittance, smooth surface morphology, and suitable WF of the surface-modified ITO.
Bibliographical noteFunding Information:
This work was supported by the Technology Innovation Program (grant number: 20011336 ) funded By the Ministry of Trade, Industry & Energy (MOTIE, Korea) . In addition, this research was also supported the Technology Development Program to Solve Climate Changes of the NRF, funded by the Ministry of Science ICT and Future Planning (NRF 2016M1A2A2940912). Finally, this work was supported by the Brain Korea 21 FOUR Project in 2021.
© 2021 The Author(s)
- Cyclodextrin–polyacryloyl hydrazide (CD–PAH)
- Electron-collecting electrode
- Indoor organic photovoltaics
- Surface modification
ASJC Scopus subject areas
- Ceramics and Composites
- Surfaces, Coatings and Films
- Metals and Alloys