The frequency dependence of the external quantum efficiency (EQE) of high-quality multijunction solar cells was examined by the modulated photocurrent spectroscopy method via an optical setup comprised of a light-pipe-coupled compact LED array. The optical excitation was achieved through sinusoidal electrical modulation of an appropriate LED by a custom-designed, high bandwidth amplifier. We observed unique features in the amplitude and phase data of the EQE frequency sweeps that are very sensitive to various subcell parameters and light bias conditions. These features are discussed extensively within the context of an AC equivalent circuit model, showing remarkable agreement between the experimental data and the proposed model.
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http://dx.doi.org/10.1364/OE.25.00A709 | DOI Listing |
Nanomaterials (Basel)
December 2024
School of Flexible Electronics (Future Technologies), Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
Two-dimensional WSe nanosheets have received increasing attention due to their excellent optoelectronic properties. Solid precursors, such as WO and Se powders, have been extensively employed to grow WSe nanosheets by the chemical vapor deposition (CVD) method. However, the high melting point of WO results in heterogeneous nucleation sites and nonuniform growth of the WSe nanosheet.
View Article and Find Full Text PDFACS Nano
December 2024
Department of Chemistry, Korea University, Seoul 02841, Republic of Korea.
Research on perovskite light-emitting diodes (PeLEDs) has primarily focused on modulating crystal growth to achieve smaller grain sizes and defect passivation using organic additives. However, challenges remain in controlling the intermolecular interactions between these organic additives and perovskite precursor ions for precise modulation of crystal growth. In this study, we synthesize two triphenylphosphine oxide (TPPO)-based multidentate additives: bidentate hexane-1,6-diyl-bis(oxy-4-triphenylphosphine oxide) (2-TPPO) and tetradentate pentaerythrityl-tetrakis(oxy-4-triphenylphosphine oxide) (4-TPPO).
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
School of Microelectronics, Shanghai University, Shanghai 200444, China.
GaN-based micro-light-emitting diodes (Micro-LEDs) are regarded as promising light sources for near-eye-display applications such as augmented reality/virtual reality (AR/VR) displays due to their high resolution, high brightness, and low power consumption. However, the application of Micro-LEDs in high-pixel-per-inch (PPI) displays is constrained by the drop in efficiency caused by sidewall defects in small-sized devices. In this study, a process method involving NH plasma pretreatment to reduce sidewall defects is proposed and investigated for enhancing the external quantum efficiency (EQE) of small-sized devices.
View Article and Find Full Text PDFAdv Mater
December 2024
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China.
Broadband photodetectors (PDs) have garnered significant attention due to their ability to detect optical signals across a wide wavelength range, with applications spanning military reconnaissance, environmental monitoring, and medical imaging. However, existing broadband detectors face several practical challenges, including limited detection range, uneven photoresponse, and difficult to distinguish multispectral signals. To address these limitations, this study presents a self-powered ultra-wide PD based on the BiSe/AlInAsSb heterojunction.
View Article and Find Full Text PDFNano Lett
December 2024
State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an 710072, P. R. China.
Dion-Jacobson (DJ) perovskites are promising alternatives for Ruddlesden-Popper (RP) perovskites to fabricate blue perovskite light-emitting diodes (PeLEDs) due to their favorable structural and charge properties. However, the relatively weak hydrogen bond between the bridging diammonium group and perovskite poses huge challenges for regulating crystallization and defect density, leading to an undesirable film quality and device performance. Herein, we report the successful optimization of DJ perovskite films by introducing a new type of cesium octafluoroadipate (CsOFAA) precursor, which could strongly anchor the perovskite through coordination bonds and halogen-halogen bonds.
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