Spray-deposited thin films of zinc oxide (ZnO) and aluminum-doped zinc oxide (Al-ZnO) are characterized in detail to get insight into the role of a dopant in the matrix. ZnO and Al-ZnO are implemented as electron transport layers (ETLs) in inverted organic solar cells (IOSCs) with PTB7-Th as a donor and IEICO-4F as a nonfullerene acceptor, forming the bulk heterojunction (BHJ) photoactive layer. Organic solar cells (OSCs) based on the ZnO ETL exhibit a short-circuit current density (JSC) of 24.46 mA/cm2 and an open-circuit voltage (VOC) of 0.68 V, yielding a power conversion efficiency (PCE) of 9.3%. A solar cell based on the Al-ZnO ETL yields a higher JSC of 25.16 mA/cm2 and a VOC of 0.71 V, resulting in a PCE of 10.5%, which indicates that Al doping improves the device performance. Time-delayed collection field (TDCF) measurements yielded field-independent charge generation for both devices. Furthermore, steady-state photoluminescence (PL), time-resolved PL, and transient absorption measurements confirm reduction in the number of defect states in Al-ZnO thin films compared to ZnO thin films and efficient charge transfer, yielding an overall improved IOSC device performance.
|Original language||English (US)|
|Journal||ACS Applied Energy Materials|
|State||Published - Feb 21 2023|
Bibliographical noteKAUST Repository Item: Exported on 2023-02-27
Acknowledged KAUST grant number(s): OSR-CARF/CCF-3079
Acknowledgements: This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Research Administration (ORA) under Award No: OSR-CARF/CCF-3079. The work is also supported by Basic Science Research Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education with Research Grant No. NRF-2022R1I1A1A01073859.