The ultrafast charge generation process in organic solar cell devices is investigated by transient reflection spectroscopy on five state-of-the-art bulk heterojunction systems. The charge generation process in operating devices is found to be a combination of an ultrafast generation mechanism over several hundred femto-seconds and a slow process from pico-seconds to nanoseconds, limited by exciton diffusion dynamics. In addition, the lack of electric field dependence in the charge dynamics rules out geminate recombination as an important loss mechanism.
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http://dx.doi.org/10.1002/adma.201405284 | DOI Listing |
ACS Nano
January 2025
School of Information Science and Technology and Department of Optical Science and Engineering and Key Laboratory of Micro and Nano Photonic Structures (MOE), Fudan University, Shanghai 200433, China.
The formation of large polarons resulting from the Fröhlich coupling of photogenerated carriers with the polarized crystal lattice is considered crucial in shaping the outstanding optoelectronic properties in hybrid organic-inorganic perovskite crystals. Until now, the initial polaron dynamics after photoexcitation have remained elusive in the hybrid perovskite system. Here, based on the terahertz time-domain spectroscopy and optical-pump terahertz probe, we access the nature of interplay between photoexcited unbound charge carriers and optical phonons in MAPbBr within the initial 5 ps after excitation and have demonstrated the simultaneous existence of both electron- and hole-polarons, together with the photogenerated carrier dynamic process.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
School of Resources and Environment, University of Electronic Science and Technology of China, Chengdu, 611731, China.
Heterojunctions, known for their decent separation of photo-generated electrons and holes, are promising for photocatalytic CO reduction. However, a significant obstacle in traditional post-assembled heterojunctions is the high interfacial barrier for charge transfer caused by atomic lattice mismatch at multiphase interfaces. Here, as research prototypes, the study creates a lattice-matched co-atomic interface within CsPbBr-CsPbBr polytypic nanocrystals (113-125 PNs) through the proposed in situ hybrid strategy to elucidate the underlying charge transfer mechanism within this unique interface.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Tianjin University, School of Chemical Engineering and Technology, Weijin Road, 300072, Tianjin, CHINA.
Phosphoric acid (H3PO4) doping is a widely employed strategy to facilitate anhydrous proton transport in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). However, significant H3PO4 leaching during long-term operation poses critical challenges to maintaining membrane stability and proton conductivity. Herein, H3PO4 is incorporated into positively charged nanochannels of quaternized covalent organic framework membranes (QACOFMs), leveraging strong electrostatic interactions and confinement effects to achieve exceptional H3PO4 retention under hydration conditions.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Key Laboratory of Photonic and Electronic Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025, China. Electronic address:
Electrocatalytic NO reduction (NORR) to NH represents a promising approach for converting hazardous NO waste gases into high-value NH products under ambient conditions. However, exploring stable, low-cost, and highly efficient catalysts to enhance the NO-to-NH conversion process remains a significant challenge. Herein, through systematic computational studies based on density functional theory (DFT), we rationally designed transition metal triatomic cluster supported on graphdiyne (TM/GDY) as potential single-cluster catalysts for high-performance NORR.
View Article and Find Full Text PDFACS Nano
January 2025
School of Chemistry and Chemical Engineering, National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094, China.
Constructing a strong bonded interface is highly desired to build fast charge-transfer channels and tune reactive sites for optimizing CO photoreduction. In this work, a covalent triazine framework (CTF) combined with a BiSBr heterojunction is designed using an electrostatic self-assembly process. Due to the oppositely charged states between two components and ultrasonic treatment, a strong coupled interface is realized with the formation of Bi-C/N/O bonds, leading to robust interfacial polarization.
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