Quantum Dot Lab

The Quantum Dot Lab, JNCASR proudly celebrates 15 years of scientific exploration, innovation, and academic excellence.

Founded with a vision to understand and engineer matter at the nanoscale, the lab has evolved into a dynamic research hub advancing both fundamental and applied science of semiconductor nanomaterials. Our work spans quantum confinement physics, doped and alloyed nanocrystals, magneto-optical phenomena, and optoelectronic energy transfer contributing to foundational insights as well as emerging technologies.

At the heart of the Quantum Dot Lab is a strong culture of scientific rigor, creativity, and interdisciplinary collaboration. Over the years, the lab has trained a diverse community of students and researchers in advanced synthesis, spectroscopy, and theoretical analysis. Many of our alumni now contribute to leading academic institutions, research laboratories, and industries worldwide.

As part of the 15-year celebrations, we were delighted to host an online alumni meet, bringing together former and current members of the lab from across the globe to reconnect, share experiences, and reflect on a shared journey of discovery.

To commemorate this milestone, we have also launched a special YouTube video capturing memories, milestones, and voices from the Quantum Dot Lab community. Watch the 15-Year Anniversary Video: https://youtu.be/-la26JmRI-c?si=lbYnr7yxOjMLeJbf

As we reflect on the past 15 years, we look ahead with optimism and ambition. The challenges of the future from quantum materials to next-generation optoelectronics, call for the same spirit that has defined our journey: thoughtful inquiry, collaborative effort, and an unwavering commitment to excellence.

We extend our sincere gratitude to our students, alumni, collaborators, mentors, and institutional supporters whose contributions form the foundation of the lab’s enduring legacy.

Here’s to 15 years of discovery and to the many breakthroughs yet to come.

Prof. Ranjani Viswanatha has been elected as a Fellow of the Indian Academy of Sciences (IAS).

A well-deserved recognition of her outstanding contributions to science, mentorship, and leadership.
Heartiest congratulations on this remarkable achievement!

Happy to share our group’s recent publication in Chemistry of Materials American Chemical Society

This project began with Mahima Makkar and was brought to completion by Subham Das. Over years of work, the team demonstrates how dopant atoms are arranged: clustered vs diffused, directly controls sp–d exchange and magneto-optical response in dilute magnetic nanocrystals.

Congratulations to the entire team on this achievement.
Link to the Full article :

Probing and Controlling Dopant Distribution in Dilute Magnetic Semiconducting Nanocrystals Precise control of magnetic dopant distribution in semiconductor nanocrystals (NCs) is essential for advancing spintronic and magneto-optical technologies. In dilute magnetic semiconductors (DMS), uncontrolled clustering disrupts sp–d exchange, reduces spin coherence, and limits device performance...

We are pleased to share our recent Perspective article published in ACS Energy Letters:

“From Mechanism to Energy Applications: Vibrationally Assisted Delayed Fluorescence in Doped Lead Halide Perovskite Nanocrystals”

Authors:
Subham Das, Soumya Panja (Joint First Authors) , and Ranjani Viswanatha

In this work, we present a comprehensive photophysical framework describing how long-lived dopant states, coupled with phonon-mediated vibronic interactions, enable vibrationally assisted delayed fluorescence (VADF) in doped lead halide perovskite nanocrystals. This mechanism enables efficient exciton recycling, suppresses nonradiative losses, and enhances photoluminescence efficiency, offering new design principles for energy-harvesting and optoelectronic applications.

📄 Read the article: https://doi.org/10.1021/acsenergylett.5c03380

From Mechanism to Energy Applications: Vibrationally Assisted Delayed Fluorescence in Doped Lead Halide Perovskite Nanocrystals Doped lead halide perovskite nanocrystals (LHP NCs) represent a promising materials platform for advanced energy conversion and light-emitting technologies. Incorporation of long-lived dopant states introduces metastable energy reservoirs that capture photogenerated carriers and recycles them into h...

Excited to share our article has been featured by Royal Society of Chemistry in ChemSci 2025.
This work is published in Chemical Science Journal this year.

In this work, we unlocked the brighter possibilities for next-gen LEDs and photovoltaics via Ni doping in CsPbCl₃ NCs. This strategy significantly boosts PLQY via charge carrier back-transfer supported by EXAFS, DFT, MCD and efficient FRET study.

Grateful to the team and collaborators who made this work possible, and excited about the opportunities open for advanced optoelectronic materials.

rsc.li/chemsci2025-in06
🔗doi.org/10.1039/D5SC00564G

Congratulations, Gauttam Dash for successfully defending his doctoral thesis entitled as "Controlling Magneto-Optical Properties and Exciton Dynamics in Metal Halide Perovskites via Plasmonic Coupling, Dimensionality, and Chirality"

Thrilled to share some recent publications! 🎉
Earlier this year, our work titled “Chemical Strain-Induced Rashba Effect in Two-Dimensional Ruddlesden–Popper Perovskites” was published in Physical Review B. Our findings reveal how chemical strain can induce local asymmetry, enabling Rashba-type spin splitting, a promising pathway for next-generation quantum and spintronic technologies.
Building on this direction, we have also written a perspective titled “A Chemical Vision for the Future of Quantum Materials: Defect and Interface Engineering at the Nanoscale,” which has been accepted for publication in Nano Futures.
https://doi.org/10.1088/2399-1984/ae10f0
Grateful to all collaborators and mentors who made these works possible!

We are excited to announce Driving Discovery through Synergy – 2025, an interdisciplinary meeting to be held at JNCASR from 15–17 September 2025.

The event will focus on key areas including perovskite halides and oxides, energy conversion and storage, quantum materials, AI/ML-enabled materials discovery, and translational research.

We especially encourage early-career researchers and senior PhD students to participate.

The official event website is now live!

🗓️ Registration closes on 31 July 2025
🔗 Visit: https://sites.google.com/view/dds-2025/home

DDS-2025 Join leading Scientists and Innovators to spark transformative solutions and discuss cross-disciplinary synergies in multidisciplinary fields

Excited to share that our manuscript titled “Plasmonic Field-Enhanced Zeeman Splitting in Ag-CsPbBr3 Hybrid Nanostructures: A Step toward Tunable Magneto-Optical Devices” has been published in The Journal of Physical Chemistry-JPC Letters

What initially started as a straightforward investigation into Ag doping in CsPbBr3 nanocrystals soon took a fascinating turn, as we realized that Ag does not readily incorporate into the perovskite lattice but instead tends to form distinct nanoparticles. This insight shifted our focus toward designing hybrid nanostructures where Ag nanoparticles were purposefully coupled with CsPbBr3 nanocrystals to harness plasmon–exciton interactions more effectively. Using localized surface plasmon resonance (LSPR) from Ag nanoparticles, we have observed significant enhancements in Zeeman splitting and magnetic circular dichroism near the nanocrystal band-edge.

Three nanoparticle arrangements- uniform, clustered, and mixed were compared, with the uniform configuration showing the strongest enhancement due to optimal exciton–plasmon overlap. The findings demonstrate the potential of plasmon–perovskite hybrids for magneto-optical sensing, spintronics, and quantum technologies highlighting the power of nanoscale design in tuning spin-resolved optical transitions.

Authored By- Gauttam Dash, Subham Das, Naveen Sheoron, Aravind Arun, and Ranjani Viswanatha
Curious about how we did it? Dive into the full story here DOI:

Plasmonic Field-Enhanced Zeeman Splitting in Ag-CsPbBr3 Hybrid Nanostructures: A Step toward Tunable Magneto-Optical Devices We present a systematic study of plasmon-enhanced magneto-optical (MO) effects in hybrid nanostructures composed of CsPbBr3 nanocrystals (NCs) coupled with silver (Ag) nanoparticles (NPs). By harnessing the intense local electric fields generated via localized surface plasmon resonance (LSPR) of Ag....

JNCASR invites enthusiastic and driven students to participate in walk-in interviews. This opportunity is specifically for those who missed the chance to apply for the advertisement published in March 2025.

We are seeking dedicated PhD candidates to join our research group. Applicants must have completed a Master's degree (M.Sc. or MS) in Physics or Chemistry from an Indian university and hold a valid UGC CSIR NET Fellowship.

Interested candidates who wish to attend the walk-in interview should email a detailed resume (including contact information), along with scanned copies of degree certificates, mark sheets, and score/award letters from relevant national-level exams (GATE/JEST/GPAT/UGC-JRF/CSIR-NET-JRF/ICMR-JRF/DBT-JRF/INSPIRE-JRF).

To learn more about our lab and ongoing research, please check out our lab poster and visit Prof. Ranjani Viswanatha's homepage: https://www.jncasr.ac.in/faculty/rv.

For further inquiries, feel free to reach out via email:
📧 Quantum Dot Lab: [email protected]
📧 Prof. Ranjani Viswanatha: [email protected]

Ranjani Viswanatha | Jawaharlal Nehru Centre for Advanced Scientific Research Prof. Ranjani Viswanatha obtained her Ph.D. from the Indian Institute of Science, Bangalore in 2006 and carried out postdoctoral research at University of Arkansas (2007-2008) and later at Los Alamos National Laboratory (2008-2010). She joined JNCASR in 2011 as Faculty Fellow.

JNCASR is inviting bright and motivated students who could not apply or could not submit their Ph.D application for various reasons in response to the advertisement published during March 2025.

Candidates who have qualified and received the results of the Joint CSIR-UGC NET for JRF- December 2024 are strongly encouraged to apply.

Important dates
Website re-opens for online submission of application: 02-05-2025
Website closes at 23:59 hours on: 10-05-2025

To apply: https://jncasr-admissions.in/

For details, visit : https://www.jncasr.ac.in/admission/degree-programmes

Degrees and Diploma Programmes | Jawaharlal Nehru Centre for Advanced Scientific Research Regular Admissions 2025-26 Advertisement in English (Click here) Advertisement in Hindi (Click here) Admissions Brochure (Click here) To apply : Go to https://www.jncasr.ac.in/admission/admissions Research Programmes and Details Regarding Eligibility Criteria, Selection Procedure, Fellowships Ph.D.....

Delighted to be a part of this special feature on Hybrid Perovskite 24 (HyPe24) in ACS Energy Letters. Sincere thanks to Prof. Narayan Pradhan, Prof. Lakshmi Polavarapu, and Prof. Prashant Kamat for their kind invitation and support.
https://pubs.acs.org/doi/10.1021/acsenergylett.5c01173