Key Takeaways & Executive Findings
- •• First demonstration of solution-phase ligand exchange (SPLE) using inorganic ligands to synthesize stable p-type PbS quantum dot inks. • Precise control of SnI2 concentration enables tunable transition of PbS QDs from n-type to p-type conductivity. • PbS CQD solar cells with inorganic ligand-passivated HTL achieve a PCE of 10.93%, outperforming the conventional EDT-based LbL method (9.83%). • The improved performance is attributed to reduced interfacial defects and enhanced carrier mobility, offering a scalable route for high-performance flexible optoelectronics.
Abstract
Traditional p-type colloidal quantum dot (CQD) hole transport layers (HTLs) used in CQD solar cells (CQDSCs) are commonly based on organic ligands exchange and the layer-by-layer (LbL) technique. Nonetheless, the ligand detachment and complex fabrication process introduce surface defects, compromising device stability and efficiency. In this work, we propose a solution-phase ligand exchange (SPLE) method utilizing inorganic ligands to develop stable p-type lead sulfide (PbS) CQD inks for the first time. Various amounts of tin (II) iodide (SnI2) were mixed with lead halide (PbX2; X = I, Br) in the ligand solution. By precisely controlling the SnI₂ concentration, we regulate the transition of PbS QDs from n-type to p-type. PbS CQDSCs were fabricated using two different HTL approaches: one with 1,2-ethanedithiol (EDT)-passivated QDs via the LbL method (control) and another with inorganic ligand-passivated QD ink (target). The target devices achieved a higher power conversion efficiency (PCE) of 10.93%, compared to 9.83% for the control devices. This improvement is attributed to reduced interfacial defects and enhanced carrier mobility. The proposed technique offers an efficient pathway for producing stable p-type PbS CQD inks using inorganic ligands, paving the way for high-performance and flexible CQD-based optoelectronic devices.
1. Introduction
Quantum dots (QDs) are semiconductor nanoparticles whose optical and electrical properties can be precisely tailored by adjusting their size and modifying their surface chemistry[1−3]. QDs synthesized from binary ionic compound semiconductors such as PbS, CdS, PbSe, CdSe, and InAs have gained significant attention in optoelectronics due to their extraordinary properties[4], including multi-exciton generation[5], solution processability[6], tunable absorption spectrum[7], and narrow emission line width[8]. The unique characteristics make QDs highly suitable for a wide range of optoelectronic applications, including light-emitting diodes[9, 10], photodetectors[11, 12], lasers[13], and photovoltaic devices[14−16].
In a typical lead sulfide colloidal quantum dot solar cell (PbS CQDSC), a several-hundred-nanometer-thick n-type CQD absorber layer (CQD AL) is strategically employed to absorb sunlight and generate charge carriers. However, the performance and stability of such devices are often limited by the quality of the hole transport layer (HTL), which is crucial for efficient charge extraction and minimizing recombination losses. Traditional HTLs rely on organic ligand exchange and layer-by-layer (LbL) deposition, which can introduce surface defects and complicate the fabrication process, thereby compromising device stability and efficiency. To address these challenges, this work introduces a solution-phase ligand exchange (SPLE) method using inorganic ligands to produce stable p-type PbS CQD inks, offering a promising alternative for high-performance and stable solar cells.
Loading authentic research manuscript (Pages 1–5)...
Napasuda Wichaiyo, Yuyao Wei, Chao Ding, Guozheng Shi, Witoon Yindeesuk, Liang Wang, Huān Bì, Jiaqi Liu, Shuzi Hayase, Yusheng Li, Yongge Yang, Qing Shen (2025). Synthesis of p-type PbS quantum dot ink via inorganic ligand exchange in solution for high-efficiency and stable solar cells. SinoTechIntel Verified Research. https://doi.org/10.1088/1674-4926/25030003
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the main innovation of this paper?
The paper presents a novel solution-phase ligand exchange (SPLE) method using inorganic ligands to synthesize stable p-type PbS quantum dot inks, which simplifies the fabrication of hole transport layers and improves solar cell performance.
How does the SnI2 concentration affect the PbS quantum dots?
By precisely controlling the SnI2 concentration, the conductivity type of PbS QDs can be tuned from n-type to p-type, enabling the formation of p-type inks suitable for hole transport layers.
What are the efficiency results compared to conventional methods?
The target devices using inorganic ligand-passivated QD ink achieved a power conversion efficiency (PCE) of 10.93%, which is higher than the 9.83% obtained from the conventional EDT-based layer-by-layer method.
What are the key advantages of the proposed method?
The proposed method reduces interfacial defects and enhances carrier mobility, leading to improved device efficiency and stability. It also offers a scalable and solution-processable route for fabricating high-performance flexible optoelectronic devices.
What is the significance of using inorganic ligands?
Inorganic ligands provide stronger passivation and better electronic coupling compared to organic ligands, resulting in reduced surface defects and improved charge transport, which are critical for high-efficiency solar cells.
Related Technical Papers & Translations
A Novel Approach for Enhanced Brain Tumor Segmentation Using Multimodal MRI and Deep Learning
Brain tumor segmentation from multimodal MRI is crucial for diagnosis and treatment planning. In this study, we propose a novel deep learning framework that integrates structural and functional imaging modalities to improve segmentation accuracy. Our method employs a multi-scale attention mechanism and a hybrid loss function to handle class imbalance and boundary ambiguity. Evaluated on the BraTS benchmark, our approach achieves state-of-the-art performance, with Dice scores of 0.91, 0.87, and 0.84 for whole tumor, core, and enhancing tumor, respectively. Furthermore, we demonstrate the generalizability of our model across different scanners and protocols. Our findings suggest that the proposed method can significantly aid clinical decision-making and surgical planning.
Investigation of coupled acoustic and electrical responses and early warning approaches during re-loading of damaged coal
Initial damage from engineering disturbances in deep coal mining degrades mechanical properties and heightens dynamic-hazard risks, challenging conventional monitoring. This study probes the coupled acoustic-electrical responses of initially damaged coal under reloading and develops a multi-parameter, multi-level dynamic integrated early-warning model. Using a true-triaxial Split Hopkinson Pressure Bar (SHPB) system, we prepared specimens with graded damage by varying static deviatoric stresses and dynamic impacts. Uniaxial compression reloading was conducted with synchronous acoustic emission (AE) and resistivity monitoring. Joint time-domain responses of force, acoustics, and electricity delineated distinct loading stages. Time-frequency features were extracted via Fourier and wavelet transforms; crack architecture was quantified by 3D AE localization and fractal-dimension analysis. Initial damage markedly reduced load-bearing capacity. Resistivity decreased sharply with increasing deviatoric stress, while cumulative AE counts increased strongly. The AE spectrum evolved from bimodal to broadband with low- and high-frequency enhancement. The resistivity spectrum showed progressive bandwidth broadening, energy amplification, and high-frequency advancement. The AE spatial fractal dimension rose significantly during compaction. An integrated warning system combining multiscale entropy fusion, Temporal Convolutional Network (TCN)-Transformer forecasting, recurrence-network analysis, and a Bayesian framework yielded a 28.4 s lead time, offering a theoretical basis and technical pathway for intelligent prevention of dynamic hazards.
Influence of aggregate particle size on fracture behavior and energy evolution of cemented rockfill in the post-peak stage
Cemented rockfill (CRF) combines structural support with sustainable reuse of coal-derived solid waste. This study integrates digital image correlation, acoustic emission monitoring, and finite–discrete element simulations to investigate mechanical behavior, fracture development, and energy evolution of CRF containing 54% aggregate content with three grain-size distributions (5–10, 10–20, and 20–30 mm). Results indicate finer aggregates raise compressive strength and elastic modulus, and increase post-peak softening and residual stiffness. Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens, with cracks initiating at boundaries and propagating inward. The proportion of failed joints at comparable strains decreases markedly with finer gradation, reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations. Energy analyses reveal a coarse > medium > fine ordering in cumulative dissipation; however, finer aggregates delay rapid kinetic and dissipative energy release, promoting slower energy redistribution and improved load resistance. These findings quantify how aggregate gradation controls deformational mechanisms, crack topology, and energy partitioning, and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility, energy absorption, and structural reliability of CRF in underground engineering.