Hetero-junction organic photovoltaic (OPV) cells consisting of donor (D) and acceptor (A) layers have been regarded as next-generation PV cells, because of their fascinating advantages, such as lightweight, low fabrication cost, resource free, and flexibility, when compared to those of conventional PV cells based on silicon and semiconductor compounds. However, the power conversion efficiency (η) of the OPV cells has been still around 8%, though more than 10% efficiency has been required for their practical use. To fully optimize these OPV cells, it is necessary that the low mobility of carriers/excitons in the OPV cells and the open circuit voltage (V OC), of which origin has not been understood well, should be improved. In this review, we address an improvement of the mobility of carriers/excitons by controlling the crystal structure of a donor layer and address how to increase the V OC for zinc octaethylporphyrin [Zn(OEP)]/C60 hetero-junction OPV cells [ITO/Zn(OEP)/C60/Al]. It was found that crystallization of Zn(OEP) films increases the number of inter-molecular charge transfer (IMCT) excitons and enlarges the mobility of carriers and IMCT excitons, thus significantly improving the external quantum efficiency (EQE) under illumination of the photoabsorption band due to the IMCT excitons. Conversely, charge accumulation of photo-generated carriers in the vicinity of the donor/acceptor (D/A) interface was found to play a key role in determining the V OC for the OPV cells.
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http://dx.doi.org/10.3402/nano.v4i0.21055 | DOI Listing |
Small
January 2025
Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong, 999077, China.
Carbazole-derived self-assembled monolayers (SAMs) are promising materials for hole-extraction layer (HEL) in conventional organic photovoltaics (OPVs). Here, a SAM Cbz-2Ph derived from 3,6-diphenylcarbazole is demonstrated. The large molecular dipole moment of Cbz-2Ph allows the modulation of electrode work function to facilitate hole extraction and maximize photovoltage, thus improving the OPV performance.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai, 200240, China.
Thanks to the development of non-fullerene acceptor (NFA) materials, the photovoltaic conversion efficiency (PCE) of organic solar cells (OSCs) has exceeded 20 %, which has met the requirements for commercialisation. In the current stage, the main focus is to balance the performance and stability. It has been shown that all-polymer formulation can improve device stability, however, PCE is not in satifsfaction, and the batch-to-batch variation leads to quality control issues.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Medium-wide-bandgap (MWBG) organic photovoltaic (OPV) cells have emerged as a promising category with distinctive application possibilities, especially in environments characterized by specific light conditions, such as indoor spaces. However, there are few high-efficiency MWBG acceptors, and most of them are constructed through high-cost fused central units, which limits the industrialization of MWBG OPV cells. Here, two completely nonfused MWBG acceptors, TBT-38 and TBT-43 with different alkoxy substituent positions on the thiophene rings, are synthesized.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Zhejiang University, Hangzhou, Zhejiang 310027, China.
Adv Mater
December 2024
Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Designing donor (D) and acceptor (A) structures and discovering promising D-A combinations can effectively improve organic photovoltaic (OPV) device performance. However, to obtain excellent power conversion efficiency (PCE), the trial-and-error structural design in the infinite chemical space is time-consuming and costly. Herein, a deep learning (DL)-assisted design framework for OPV materials is proposed.
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