Among the wide array of quantum dot materials, indium phosphide (InP)-based quantum dots have garnered substantial attention due to their environmental friendliness and outstanding performance metrics. Unlike traditional cadmium-based quantum dots, which raise toxicity concerns owing to heavy metal content, InP quantum dots offer a non-toxic alternative, broad spectral tunability, and notable optical stability. These properties have motivated intense research efforts to leverage InP quantum dots as the cornerstone for sustainable, high-performance display technologies destined to replace their cadmium counterparts while meeting stringent environmental regulations.

Despite the theoretical advantages of InP quantum dots, their practical implementation faces several formidable challenges. Paramount among these is the ability to synthesize InP cores exhibiting uniform size distribution, high crystallinity, and minimal surface defects, all of which directly influence the photoluminescence quantum yield and emission linewidth. Conventional synthesis protocols often fall short of these requirements, resulting in batch-to-batch inconsistencies, broad emission spectra, and reduced luminous efficiency. The synthesis challenge is particularly pronounced for blue-emitting InP quantum dots, whose performance currently lags behind their cadmium-based analogues, hindering the realization of full-spectrum, high-efficiency displays.

In a comprehensive review published in the March 2026 volume of Opto-Electronic Advances, a multidisciplinary team led by Yangyang Bian from Beijing Jiaotong University, in collaboration with Professors Aiwei Tang and Fei Chen, systematically dissects recent breakthroughs and ongoing obstacles in InP quantum dot research. The authors delve into the intricate nucleation mechanisms governing InP core formation, elucidating how precise control over nucleation kinetics enables the tailored growth of high-quality cores, a critical precursor to superior device performance. This mechanistic understanding serves as the foundation for innovating synthesis strategies aimed at achieving consistent quantum dot morphology and defect passivation.

Beyond the core synthesis, the review underscores the significance of core/shell architectures in enhancing quantum dot performance. Encapsulation of InP cores within carefully engineered alloyed shells not only passivates surface traps but also modulates band alignment, thereby improving charge carrier confinement and stability. The authors highlight the interplay between shell composition, thickness, and lattice matching, which collectively dictate the photostability and emission efficiency. Such rational shell engineering is vital for mitigating non-radiative recombination pathways that otherwise degrade quantum yield, especially under prolonged electrical excitation in quantum dot light-emitting diodes (QLEDs).

Surface chemistry and ligand engineering emerge as pivotal factors in optimizing InP quantum dots for device integration. The review discusses advanced passivation techniques that employ tailored organic ligands to stabilize quantum dot surfaces, prevent agglomeration, and facilitate charge injection within QLED architectures. Ligand design directly influences the electronic coupling between quantum dots and adjacent charge transport layers, impacting charge injection balance and recombination dynamics. The authors also address recent progress in minimizing ligand-induced charge transfer barriers without compromising surface protection, a key challenge for achieving high photoluminescence quantum yields and operational stability.

The discussion extends into the domain of device physics, where interfacial doping, energetic level alignment, and charge carrier balance are analyzed comprehensively. The review brings to light novel strategies for tuning the energy landscape within both conventional and inverted QLED configurations, emphasizing the critical role of interface engineering in reducing leakage currents and enhancing device efficiency. By synchronizing the energetics of quantum dot layers with adjacent electron and hole transport layers, researchers can significantly boost brightness and operational lifetime, thus moving closer to commercially viable InP QLED displays.

A distinctive aspect of this review lies in its holistic perspective, which interlinks nucleation kinetics, quantum dot surface chemistry, core/shell design, ligand engineering, and device architecture into a unified framework. This integrative approach transcends traditional compartmentalized studies, offering a deep insight into how microscopic material properties translate to macroscopic device performance. Such a comprehensive overview provides a strategic roadmap for overcoming the multifaceted challenges inherent in the development of InP-based quantum dot technologies.

The authors stress the strategic importance of addressing blue-emitting InP quantum dots, which currently constitute the bottleneck in achieving devices with full color gamut and balanced emission intensities. Novel synthesis routes, advanced shell materials, and innovative ligand formulations are emphasized as urgent areas of investigation. Moreover, understanding the underlying physical and chemical causes of emissive inefficiencies in this wavelength range is highlighted as a priority for advancing the entire field.

This review not only charts the progress of InP quantum dots as environmentally friendly alternatives but also gestures towards their broader implications in flexible electronics and emerging technologies such as augmented reality (AR) and virtual reality (VR). The scalability, color purity, and operational stability of InP QLEDs position them as critical enablers for the next generation of wearable and foldable electronic devices, expanding the horizons of quantum dot applications beyond traditional display panels.

The collaborative international nature of this research, combining expertise from Beijing Jiaotong University and Henan University, embodies the spirit of innovation driving the field forward. The teams, rich in academic achievements and technological patents, underscore the importance of interdisciplinary and cross-institutional cooperation in solving complex scientific challenges. Their efforts, supported by substantial national funding, reflect the prioritization of sustainable materials research at a global level.

Looking ahead, it is anticipated that the detailed mechanistic insights and integrative strategies outlined in this review will accelerate the adoption of InP-based quantum dots in commercial displays, lighting solutions, bio-imaging, and photodetection. As these challenges are progressively overcome, InP quantum dots are poised to displace cadmium-based materials, ushering in an era of high-performance, low-environmental-impact optoelectronics. This evolution promises enhanced device functionality coupled with sustainability, aligning with global imperatives for greener technologies.

In conclusion, the reviewed work provides a critical scientific foundation for the ongoing refinement and deployment of InP quantum dot technology. By meticulously linking core synthesis phenomena with device operational parameters, it charts a clear course toward overcoming existing limitations. The integration of precise nucleation control, advanced surface passivation, thoughtful ligand design, and optimized device engineering defines the roadmap for achieving high efficiency, brightness, and durability in InP-based quantum dot light-emitting diodes, solidifying their role as key materials for the future of optoelectronics.

Subject of Research: Not applicable
Article Title: Overcoming challenges in InP-based quantum dots: from nucleation mechanisms to high-performance quantum dot light-emitting diodes
News Publication Date: 24-Mar-2026
Web References: https://doi.org/10.29026/oea.2026.250270
References: https://doi.org/10.29026/oea.2026.250270
Image Credits: Opto-Electronic Journals Group

Keywords: indium phosphide, InP quantum dots, nucleation mechanisms, quantum dot synthesis, core/shell structures, ligand engineering, quantum dot light-emitting diodes, QLED, optoelectronics, blue emission, surface passivation, charge injection, display technology

Near-infrared (NIR) photodetection has long been a critical area of research due to its vital role in fields such as biomedical imaging, environmental monitoring, and telecommunications. However, traditional detectors often face challenges concerning sensitivity, operational stability, and scalability. The recent development reported by Zhan, Li, Chen, et al., presents a transformative approach by integrating colloidal quantum dots into phototransistor architectures, thereby significantly enhancing the responsivity to NIR wavelengths while minimizing power consumption.

Colloidal quantum dots (CQDs) are semiconductor nanocrystals renowned for their size-tunable bandgaps and exceptional photophysical characteristics. Their solution-processability enables cost-effective, large-area device fabrication, contrasting sharply with the intricate manufacturing requirements of conventional semiconductor photodetectors. The research team exploited these advantages to engineer phototransistors capable of detecting extremely low photon fluxes, a capability essential for reducing harmful radiation exposure in medical diagnostics and improving detection in dimly lit environments.

The heart of this innovation lies in the delicate balance between the photoconductive gain and the noise characteristics within the CQD phototransistor. By carefully tailoring the surface chemistry and interface engineering of the quantum dots, the researchers achieved efficient charge separation and transport, which are pivotal for high photodetection sensitivity. These modifications suppressed recombination losses and enhanced carrier mobility, resulting in a device that maintains a high signal-to-noise ratio even at minimal incident light intensities.

Moreover, the device design integrates a strategic layering of CQDs with complementary semiconductor materials to facilitate charge transfer and amplify photocurrent generation. This heterojunction configuration not only optimizes the absorption spectrum extent into the near-infrared but also stabilizes the operational environment against ambient oxygen and moisture, factors commonly detrimental to quantum dot performance over time. The resulting phototransistor exhibits remarkable device stability, a critical parameter for real-world deployment.

The capability to operate efficiently under low-dose NIR illumination presents profound implications for medical imaging technologies. Minimizing exposure to potentially harmful radiation without compromising image clarity can significantly advance non-invasive diagnostic procedures. These CQD phototransistors can be integrated into flexible, wearable devices, revolutionizing patient monitoring where continuous and sensitive detection of physiological signals in the near-infrared regime is paramount.

In addition to biomedical applications, the breakthrough extends to image communication systems. Near-infrared light is increasingly used in secure communication due to its penetration abilities and low ambient interference. Phototransistors developed in this study offer enhanced responsivity that can support higher data transmission rates with improved signal integrity, propelling advances in optical wireless communication protocols and encryption technologies.

Technically, the research delineates a robust fabrication protocol where CQDs were synthesized with controlled size distribution, ensuring spectral uniformity crucial for reproducible device performance. Advanced ligand-exchange processes rendered the quantum dot surfaces with high electronic coupling, facilitating efficient charge transport networks. Detailed spectral analysis confirmed the phototransistors’ peak sensitivity aligning with target NIR wavelengths, thus validating their practical applicability.

Extensive characterization of the devices revealed a responsivity exceeding current benchmarks by a significant margin, with detectivity metrics indicative of profound sensitivity enhancements. The rise and fall times of the phototransistors proved shorter than comparable devices, suggesting potential for rapid modulation and real-time signal processing capabilities essential in dynamic imaging and communication scenarios.

The interdisciplinary collaboration driving this research combined expertise in nanomaterials chemistry, semiconductor physics, and device engineering. This synergy enabled the exploration of complex interfacial phenomena governing carrier dynamics within CQD films, yielding insights instrumental for fine-tuning phototransistor architectures. Computational modeling supplemented experimental findings, providing predictive capabilities to optimize device parameters further.

Moreover, the scalable nature of the fabrication technique underscores the potential for commercialization. Solution-based processing paves the way for cost-effective manufacturing on flexible substrates, allowing integration into wearable electronics, portable sensors, and large-area imaging panels. This flexibility meets the growing demand for adaptable, high-performance photodetectors in next-generation technological landscapes.

Looking forward, the research team anticipates expanding the spectral sensitivity range by engineering CQDs with different compositions, aiming to tailor devices for diverse spectral regimes beyond near-infrared. Additionally, efforts to enhance the environmental robustness and long-term operational reliability remain focal points to ensure applicability in varied climatic and usage conditions.

This breakthrough heralds a new era where colloidal quantum dot phototransistors deliver both the sensitivity and adaptability required for cutting-edge near-infrared photodetection and communication. As the scientific community continues to unravel quantum dot materials’ full potential, such innovative devices are poised to become foundational components in the evolving ecosystem of photonic technologies.

The innovative approach combining materials science and device engineering in this study exemplifies the progress toward harnessing nanoscale phenomena for macroscopic technological impact. It also exemplifies how emerging nanotechnologies can intersect with practical application domains, offering solutions that are both sophisticated and accessible.

In conclusion, the development of high-responsivity colloidal quantum dot phototransistors represents a significant leap forward in the field of near-infrared detection. These devices promise to enhance the sensitivity and efficiency of photodetection systems used across multiple industries, stimulating further research and potential commercialization in a rapidly evolving photonic landscape.

Article Title:
High responsivity colloidal quantum dots phototransistors for low-dose near-infrared photodetection and image communication

Article References:
Zhan, S., Li, B., Chen, T. et al. High responsivity colloidal quantum dots phototransistors for low-dose near-infrared photodetection and image communication. Light Sci Appl 14, 201 (2025). https://doi.org/10.1038/s41377-025-01853-7

Image Credits:
AI Generated

DOI:
https://doi.org/10.1038/s41377-025-01853-7