Room-Temperature Ambient Synthesis of Device-Ready AgBiSe2 Quantum Dot Inks for Photovoltaic Applications

Xuan Qi^a, Anatol Prudnikau^a, Angelika Wrzesińska-Lashkova^a^,^b, Julius Brunner^a^,^b, Lea Haase^a, Yana Vaynzof^a^,^b, Fabian Paulus^a

^aLeibniz Institute for Solid State and Materials Research Dresden (IFW), Helmholtzstraße 20, 01069 Dresden, Germany

^bChair for Emerging Electronic Technologies, TUD Dresden University of Technology, Nöthnitzer Str. 61, 01187 Dresden, Germany

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

C2 Advances in low-dimensional Nanocrystals: Fundamental approaches and technological perspectives

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Zhuoying Chen, Fabian Paulus, Carmelita Rodà and Matteo Zaffalon

Poster, Xuan Qi, 912
Publication date: 15th December 2025

Colloidal silver bismuth selenide (AgBiSe₂) quantum dots (CQDs) are an emerging I–V–VI₂ metal chalcogenide material system that has attracted growing interest as an environmentally-friendly semiconductor absorber for photovoltaics. Conventional CQDs production typically relies on hot-injection synthesis at high temperature under vacuum or inert conditions, and long-chain ligands are commonly used to maintain colloidal stability. However, device manufacturing is still constrained by a long-standing processing bottleneck: the long-chain, insulating ligands impede electronic coupling in the solid state and need to be replaced. As a result, device fabrication typically relies on ligand-exchange treatments and repeated layer-by-layer (LbL) deposition to enable charge transport across the CQD active layer.

Here, we report a room-temperature, ambient-condition synthetic strategy that produces a device-ready AgBiSe₂ QD ink via synthesis-integrated short-chain thiol capping. The short ligands are introduced in situ during QDs nucleation and growth, producing small QDs well-dispersed in solution with excellent colloidal stability. The resulting ink allows a direct use for device fabrication and a single step layer formation, eliminating conventional LbL assembly. Solar cells fabricated from the as-prepared ink deliver power conversion efficiencies achieving 2.97%, surpassing prior AgBiSe₂ QDs devices, while substantially simplifying the process flow. The ink also exhibits excellent long-term colloidal stability and dispersibility after months of storage, remaining directly usable for device fabrication. More broadly, this work shifts ligand engineering from a post-synthetic modification to a synthesis-stage design principle, providing a scalable and manufacturing-oriented route for solution-processed QD photovoltaic devices.

References:

[1] Yuan, M.; Liu, M.; Sargent, E. Colloidal Quantum Dot Solids for Solution-Processed Solar Cells. Nat. Energy 2016, 1, 16016.

[2] Duan, L.; Hu, L.; Guan, X.; Lin, C.; Chu, D.; Huang, S.; Liu, X.; Yuan, J.; Wu, T. Quantum Dots for Photovoltaics: A Tale of Two Materials. Adv. Energy Mater. 2021, 11 (20).

[3] Kubo, T.; Wang, H.; Segawa, H. Solution-Processed Quantum-Dot Solar Cells. In Comprehensive Renewable Energy, 2nd ed.; Elsevier, 2022; pp 1215–1266.

[4] Fan, F. Z.; Kanjanaboos, P.; Kramer, I.; Zhitomirsky, D.; Lee, P.; Perelgut, A.; Hoogland, S.; Sargent, E. H. Passivation Using Molecular Halides Increases Quantum Dot Solar Cell Performance. Adv. Mater. 2016, 28, 299–304.

[5] Akgul, M. Z.; Konstantatos, G. AgBiSe₂ Colloidal Nanocrystals for Use in Solar Cells. ACS Appl. Nano Mater. 2021, 4 (3), 2887–2894.

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