Machine learning for microscopy data analytics targeting real-time optical characterization of semiconductor nanocrystals Amitrajit Mukherjee, Robby Reynaerts, Bapi Pradhan, Sudipta Seth, Andreas T. Rösch, et al. Nature Communications, 2026 Semiconductor nanocrystals with uniform morphology and composition are expected to show consistent responses during light-matter interactions. However, microscopy reveals significant variations in their photoluminescence blinking patterns, even under identical experimental conditions. This discrepancy arises from differences in crystal defects and nonradiative trap states. As a result, heterogeneous blinking patterns serve as valuable indicator of material quality, uncovering several concealed features through statistical analysis of large datasets. Nonetheless, efficient segregation and analysis of numerous blinking trajectories remain a challenge due to laborious calculations, computational bottlenecks, and manual intervention. In this study, we introduce a robust unsupervised machine learning (UML) assisted module to cluster high-dimensional blinking patterns in near-real-time, while calculating category-wise power spectral densities (PSD) to investigate active traps. Furthermore, we explore the impact of data preprocessing on clustering performance. The ‘clustering-segregation-analysis’ (UML-PSD) methodology demonstrates versatility, paving a way to advance contemporary (micro)spectroscopy, specifically for rapid and cost-effective optical characterization of semiconductor nanocrystals.
Arm-Length-Controlled CsPbBr3 Nanocrystals for Tunable Optical and Assembly Behavior Irina Skvortsova, Sudipta Seth, Juliette Zito, Robin Girod, Bob Van Hout, et al. Advanced Materials, 2026 Colloidal cesium lead bromide (CsPbBr 3 ) nanocrystals (NCs) are excellent candidates for various photonic and optoelectronic applications due to their bright and stable green emission. Here, we establish arm length control as a central structural parameter that governs both the optical properties of individual CsPbBr 3 NCs and their self‐assembly behavior. Armed NCs, featuring a cubic core with multiple protruding arms, are synthesized by controlling seed size, concentration, and injection temperature, while arm length is tuned via cesium oleate concentration. Prolonged storage in toluene is shown to lead to a time‐dependent morphological evolution from armed NCs to 26‐faceted rhombicuboctahedra, with short‐armed structures as intermediates. NCs with a longer arm length yield enhanced radiative efficiency, extended photoluminescence (PL) lifetimes, and suppressed blinking, making such NCs suitable for light‐emitting devices and quantum photonic applications. In contrast, short‐armed NCs exhibit faster recombination, stronger PL intermittency, and increased surface accessibility, which are favorable for sensing and high‐speed single‐photon emission. The arm length also governs self‐assembly behavior, hereby opening new possibilities for applications. Armed NCs form densely 3D‐packed assemblies with tunable configurations. This work demonstrates how arm length tuning expands the functional potential of CsPbBr 3 NCs by linking morphological control to both optical response and self‐assembly characteristics.
Programmable Shape-Directed Optical Binding of Plasmonic Nanoparticles Jim Jui‐Kai Chen, Ashish Kar, Pengfei Yu, Ana Sánchez Iglesias, Chih‐Hao Huang, et al. Advanced Optical Materials, 2025 Controlling the organization of plasmonic nanoparticles with optical forces is essential for designing reconfigurable light‐responsive materials. However, the role of particle shape in determining optical binding geometries remains unresolved. Here, it is demonstrated that the interplay between gold nanoparticle (Au NP) morphology and optical scattering governs distinct near‐field and far‐field configurations under optical trapping at a water‐glass interface. Au spheres, rods, plates, and decahedra exhibit characteristic orientations and binding behaviors that directly correlate with their shape‐dependent scattering responses to linearly polarized near‐infrared lasers. By tuning the trapping wavelength, transitions in interparticle spacing, orientation, and collective arrangement are induced across two‐, three‐, and five‐particle systems. These results establish NP shape as a versatile design parameter for programming optical matter, offering new opportunities for dynamic nanoscale assembly, tunable plasmonic interactions, and light‐driven metamaterials.
In Operando Locally-Resolved Photophysics in Perovskite Solar Cells by Correlation Clustering Imaging Boris Louis, Sudipta Seth, Qingzhi An, Ran Ji, Yana Vaynzof, et al. Advanced Materials, 2025 The instability of metal halide perovskites limits the commercialization of solar cells despite their impressive efficiencies. This instability, driven by photo‐induced ion migration, leads to material restructuring, defect formation, degradation, and defect healing. However, these same “unwanted” properties enable to propose Correlation Clustering Imaging (CLIM), a technique that detects local photoluminescence (PL) fluctuations through wide‐field fluorescence microscopy. It is shown that such fluctuations are present in high‐quality perovskites and their corresponding solar cells. CLIM successfully visualizes the polycrystalline grain structure in perovskite films, closely matching electron microscopy images. The analysis of fluctuations reveals a dominant metastable defect responsible for the fluctuations. In solar cells in short‐circuit conditions, these fluctuations are significantly larger, and corresponding correlated regions extend up to 10 micrometers, compared to 2 micrometers in films. It is proposed that the regions resolved by CLIM in solar cells possess a common pool of charge extraction channels, which fluctuate and cause PL to vary. Since PL fluctuations reflect non‐radiative recombination processes, CLIM provides valuable insights into the structural and functional dynamics of carrier transport, ion migration, defect behavior, and recombination losses. CLIM offers a non‐invasive approach to understanding luminescent materials and devices in operando, utilizing contrasts based on previously untapped properties.
From halide perovskite nanocrystals to supercrystals: fundamentals and applications S. L. Aneesha, Yifei Xia, Takuya Okamoto, Deepika Gaur, Sudipta Seth, et al. Chemical Society Reviews, 2025 Halide perovskite supercrystals (or superlattices) are electronically coupled nanomaterials, such as nanocrystals, quantum dots, or nanoplatelets that offer collective optical and electronic properties distinct from those of their constituents.
Unconventional Optical Matter of Hybrid Metal-Dielectric Nanoparticles at Interfaces Boris Louis, Chih-Hao Huang, Marc Melendez, Ana Sánchez-Iglesias, Jorge Olmos-Trigo, et al. ACS Nano, 2024 Optical matter, a transient arrangement formed by the interaction of light with micro/nanoscale objects, provides responsive and highly tunable materials that allow for controlling and manipulating light and/or matter. A combined experimental and theoretical exploration of optical matter is essential to advance our understanding of the phenomenon and potentially design applications. Most studies have focused on nanoparticles composed of a single material (either metallic or dielectric), representing two extreme regimes, one where the gradient force (dielectric) and one where the scattering force (metallic) dominates. To understand their role, it is important to investigate hybrid materials with different metallic-to-dielectric ratios. Here, we combine numerical calculations and experiments on hybrid metal-dielectric core-shell particles (200 nm gold spheres coated with silica shells with thicknesses ranging from 0 to 100 nm). We reveal how silica shell thickness critically influences the essential properties of optical binding, such as interparticle distance, reducing it below the anticipated optical binding length. Notably, for silica shells thicker than 50 nm, we observed a transition from a linear arrangement perpendicular to polarization to a hexagonal arrangement accompanied by a circular motion. Further, the dynamic swarming assembly changes from the conventional dumbbell-shaped to lobe-like morphologies. These phenomena, confirmed by both experimental observations and dynamic numerical calculations, demonstrate the complex dynamics of optical matter and underscore the potential for tuning its properties for applications.
Arm‐Length‐Controlled CsPbBr 3 Nanocrystals for Tunable Optical and Assembly Behavior I Skvortsova, S Seth, J Zito, R Girod, B Van Hout, A De Backer, T Stoops, ... Advanced Materials 38 (23), e19211 , 2026 2026 Citations: 1
Room temperature collective blinking and photon bunching from CsPbBr 3 quantum dot superlattice Q Tan, S Seth, B Louis, X Wu, N Pathoor, T Takagi, S Omagari, ... Nature Communications , 2026 2026
High Resolution Imaging of Nonequilibrium Colloidal Self-Assembly via Photofixation J Satpathy, JJK Chen, G Wen, H Masuhara, S Seth, V Leen, S Rocha, ... ACS nano 20 (7), 6287-6299 , 2026 2026
Machine learning for microscopy data analytics targeting real-time optical characterization of semiconductor nanocrystals A Mukherjee, R Reynaerts, B Pradhan, S Seth, AT Rösch, T Banerjee, ... Nature Communications , 2026 2026
Programmable Shape‐Directed Optical Binding of Plasmonic Nanoparticles JJK Chen, A Kar, P Yu, AS Iglesias, CH Huang, J Satpathy, J Wang, ... Advanced Optical Materials 13 (34), e03071 , 2025 2025 Citations: 1
M3Scope a 3D multimode multiplane microscope for imaging nanoscale dynamics in soft matter S Huysecom, F Bevilacqua, RB Obach, S Seth, LM Liz-Marzan, J Hofkens, ... arXiv preprint arXiv:2511.10174 , 2025 2025
Microscopic Intricacies of Self-Healing in Halide Perovskite-Charge Transport Layer Heterostructures T Behera, B Louis, L Paesen, RV Brande, K Asano, M Vacha, M Roeffaers, ... arXiv preprint arXiv:2510.11948 , 2025 2025
From mapping to manipulation: 3D insights into dielectrophoresis and electrokinetics for advanced sorting toward colloidal memory applications F de Jong, P Diez-Silva, JK Chen, S Seth, H Balakrishnan, BY Shih, ... Molecular and Nanophotonic Machines, Devices, and Applications VIII 13592, 53-59 , 2025 2025
Three-dimensional optical reconstruction of colloidal electrokinetics via multiplane imaging F de Jong, P Diez-Silva, JK Chen, R Pérez-Peláez, S Seth, ... arXiv preprint arXiv:2503.23839 , 2025 2025 Citations: 2
INTERMITTENCY OF THE NEAR-INFRARED LUMINESCENCE FROM CsPbBr3 MICROCRYSTALS J Vandenwijngaerden, D Santantonio, H Balakrishnan, R Bresoli-Obach, ... Near-Infrared Luminescence from Deep Defects in CsPbBr3 Perovskite, 177 , 2025 2025
Unveiling the local fate of charge carriers in halide perovskite thin films via correlation clustering imaging S Seth, B Louis, K Asano, T Van Roy, MBJ Roeffaers, E Debroye, ... Chemical & Biomedical Imaging 3 (4), 244-252 , 2025 2025 Citations: 7
In Operando Locally‐Resolved Photophysics in Perovskite Solar Cells by Correlation Clustering Imaging B Louis, S Seth, Q An, R Ji, Y Vaynzof, J Hofkens, IG Scheblykin Advanced Materials 37 (7), 2413126 , 2025 2025 Citations: 16
From halide perovskite nanocrystals to supercrystals: fundamentals and applications SL Aneesha, Y Xia, T Okamoto, D Gaur, S Seth, J Hofkens, L Polavarapu, ... Chemical Society Reviews 54, 9585-9611 , 2025 2025 Citations: 10
Unconventional Optical Matter of Hybrid Metal–Dielectric Nanoparticles at Interfaces B Louis, CH Huang, M Melendez, A Sánchez-Iglesias, J Olmos-Trigo, ... ACS nano 18 (47), 32746-32758 , 2024 2024 Citations: 11
Enhancing the X-ray Sensitivity of Cs 2 AgBiBr 6 Double Perovskite Single Crystals through Cation Engineering D Valli, H Zhang, M Betušiak, G Romolini, A Meulemans, D Escudero, ... ACS Applied Optical Materials 2 (10), 2075-2084 , 2024 2024 Citations: 17
High resolution imaging of non-equilibrium colloidal self-assembly enabled by photopolymerization J Satpathy, JK Chen, G Wen, H Masuhara, S Seth, V Leen, S Rocha, ... ChemRxiv 2024 (0920) , 2024 2024 Citations: 1
Amine‐Free Multi‐Faceted CsPbBr 3 Nanocrystals for Complete Suppression of Long‐Lived Dark States NVS Praneeth, S Akhil, A Mukherjee, S Seth, S Khatua, N Mishra Advanced Optical Materials 12 (16), 2303222 , 2024 2024 Citations: 17
Correlation Clustering Imaging: A method for Functional Mapping of Semiconductor materials and photovoltaic devices in operando B Louis, S Seth, Q An, R Ji, Y Vaynzof, J Hofkens, I Scheblykin ChemRxiv 2024 (0308) , 2024 2024 Citations: 1
Photoluminescence Polarization of MAPbBr 3 Perovskite Nanostructures. Can the Dielectric Contrast Effect Explain It? J Shi, I Ryabov, S Seth, PA Frantsuzov, S Rafie-Zinedine, A Walther, ... Acs Photonics 9 (12), 3888-3898 , 2022 2022 Citations: 3
Presence of Maximal Characteristic Time in Photoluminescence Blinking of MAPbI 3 Perovskite S Seth, EA Podshivaylov, J Li, M Gerhard, A Kiligaridis, PA Frantsuzov, ... Advanced Energy Materials 11 (44), 2102449 , 2021 2021 Citations: 26
MOST CITED SCHOLAR PUBLICATIONS
Tackling the Defects, Stability, and Photoluminescence of CsPbX 3 Perovskite Nanocrystals S Seth, T Ahmed, A De, A Samanta ACS Energy Letters 4 (7), 1610-1618 , 2019 2019 Citations: 335
Boosting the Photoluminescence of CsPbX 3 (X = Cl, Br, I) Perovskite Nanocrystals Covering a Wide Wavelength Range by Postsynthetic Treatment with … T Ahmed, S Seth, A Samanta Chemistry of Materials 30 (11), 3633-3637 , 2018 2018 Citations: 323
A Facile Methodology for Engineering the Morphology of CsPbX 3 Perovskite Nanocrystals under Ambient Condition S Seth, A Samanta Scientific reports 6 (1), 37693 , 2016 2016 Citations: 196
Fluorescence Blinking and Photoactivation of All-Inorganic Perovskite Nanocrystals CsPbBr 3 and CsPbBr 2 I S Seth, N Mondal, S Patra, A Samanta The journal of physical chemistry letters 7 (2), 266-271 , 2016 2016 Citations: 193
Fluorescent Phase-Pure Zero-Dimensional Perovskite-Related Cs 4 PbBr 6 Microdisks: Synthesis and Single-Particle Imaging Study S Seth, A Samanta The Journal of Physical Chemistry Letters 8 (18), 4461-4467 , 2017 2017 Citations: 163
Photoluminescence of zero-dimensional perovskites and perovskite-related materials S Seth, A Samanta The Journal of Physical Chemistry Letters 9 (1), 176-183 , 2018 2018 Citations: 126
Are Shockley-Read-Hall and ABC models valid for lead halide perovskites? A Kiligaridis, PA Frantsuzov, A Yangui, S Seth, J Li, Q An, Y Vaynzof, ... Nature communications 12 (1), 3329 , 2021 2021 Citations: 120
Broadband ultrafast nonlinear optical studies revealing exciting multi-photon absorption coefficients in phase pure zero-dimensional Cs 4 PbBr 6 perovskite films KN Krishnakanth, S Seth, A Samanta, SV Rao Nanoscale 11 (3), 945-954 , 2019 2019 Citations: 102
Broadband femtosecond nonlinear optical properties of CsPbBr 3 perovskite nanocrystals KN Krishnakanth, S Seth, A Samanta, SV Rao Optics letters 43 (3), 603-606 , 2018 2018 Citations: 97
Photoluminescence Flickering and Blinking of Single CsPbBr 3 Perovskite Nanocrystals: Revealing Explicit Carrier Recombination Dynamics S Seth, T Ahmed, A Samanta The Journal of Physical Chemistry Letters 9 (24), 7007-7014 , 2018 2018 Citations: 93
Mechanistic Investigation of the Defect Activity Contributing to the Photoluminescence Blinking of CsPbBr 3 Perovskite Nanocrystals T Ahmed, S Seth, A Samanta ACS nano 13 (11), 13537-13544 , 2019 2019 Citations: 91
Dark excitons of the perovskites and sensitization of molecular triplets N Mondal, A De, S Seth, T Ahmed, S Das, S Paul, RK Gautam, A Samanta ACS Energy Letters 6 (2), 588-597 , 2021 2021 Citations: 33
Differences in the behavior of dicationic and monocationic ionic liquids as revealed by time resolved-fluorescence, NMR and fluorescence correlation spectroscopy D Majhi, S Seth, M Sarkar Physical Chemistry Chemical Physics 20 (11), 7844-7856 , 2018 2018 Citations: 29
Presence of Maximal Characteristic Time in Photoluminescence Blinking of MAPbI 3 Perovskite S Seth, EA Podshivaylov, J Li, M Gerhard, A Kiligaridis, PA Frantsuzov, ... Advanced Energy Materials 11 (44), 2102449 , 2021 2021 Citations: 26
ACS Energy Lett. 2019, 4, 1610; c) H. Huang, MI Bodnarchuk, S. V. Kershaw, MV Kovalenko, AL Rogach S Seth, T Ahmed, A De, A Samanta ACS Energy Lett 2, 2071 , 2017 2017 Citations: 21
Enhancing the X-ray Sensitivity of Cs 2 AgBiBr 6 Double Perovskite Single Crystals through Cation Engineering D Valli, H Zhang, M Betušiak, G Romolini, A Meulemans, D Escudero, ... ACS Applied Optical Materials 2 (10), 2075-2084 , 2024 2024 Citations: 17
Amine‐Free Multi‐Faceted CsPbBr 3 Nanocrystals for Complete Suppression of Long‐Lived Dark States NVS Praneeth, S Akhil, A Mukherjee, S Seth, S Khatua, N Mishra Advanced Optical Materials 12 (16), 2303222 , 2024 2024 Citations: 17
Highly efficient energy transfer from fluorescent gold nanoclusters to organic j-aggregates S Banerjee, N Preeyanka, H Dey, S Seth, A Rahaman, M Sarkar The Journal of Physical Chemistry C 124 (9), 5009-5020 , 2020 2020 Citations: 17
Electrostatically Driven Förster Resonance Energy Transfer between a Fluorescent Metal Nanoparticle and J-Aggregate in an Inorganic–Organic Nanohybrid Material AK Agrawal, PK Sahu, S Seth, M Sarkar The Journal of Physical Chemistry C 123 (6), 3836-3847 , 2019 2019 Citations: 17
In Operando Locally‐Resolved Photophysics in Perovskite Solar Cells by Correlation Clustering Imaging B Louis, S Seth, Q An, R Ji, Y Vaynzof, J Hofkens, IG Scheblykin Advanced Materials 37 (7), 2413126 , 2025 2025 Citations: 16