Ink engineering approach boosts efficiency and cuts cost of quantum dot-based photovoltaics

Colloidal quantum dots (CQDs) are tiny semiconductor particles which might be only a few nanometers in measurement, that are synthesized in a liquid answer (i.e., colloid). These single-crystal particles, created by breaking down bulk supplies by way of chemical and bodily processes, have proved to be promising for the event of photovoltaic (PV) applied sciences.

Quantum dot-based PVs may have numerous benefits, together with a tunable bandgap, higher flexibility and answer processing. Nonetheless, quantum dot-based solar cells developed up to now have been discovered to have vital limitations, together with decrease efficiencies than typical silicon-based cells and excessive manufacturing prices, as a result of costly processes required to synthesize conductive CQD movies.

Researchers at Soochow College in China, the College of Electro-Communications in Japan and different institutes worldwide lately launched a brand new methodology that might doubtlessly assist to enhance the efficiencies of quantum-dot based mostly photovoltaics, whereas additionally reducing their manufacturing prices. Their proposed strategy, outlined in a paper published in Nature Powerentails the engineering of lead sulfide (PbS) CQD inks used to print movies for photo voltaic cells.

“When people discuss colloidal quantum dots (CQDs), the first thing that comes to mind is their extremely attractive size-dependent quantum properties, as well as the compatibility with low-cost solution-based fabrication methods, which open up exciting possibilities for next-generation semiconductor materials especially in printable solar cells and optoelectronic devices,” Guozheng Shi and Zeke Liu, co-author of the paper, instructed Tech Xplore.

“However, these potential applications are often overshadowed by the complex and expensive synthesis and manufacturing processes required to produce conductive CQD films.”

The delicate and costly processes at present used to supply conductive CQD movies attain a restricted yield, with the prices of CQD lively layers starting from $0.25 to $0.84/Wp, that are too excessive for his or her commercialization. Furthermore, present processes supply restricted management over the standard of the supplies and thus the ensuing photo voltaic cells.

“Earlier than our work, CQD photo voltaic modules exceeding 10 cm² achieved solely ~1% power conversion efficiency (PCE), a stark distinction to the over 12% PCE of lab-scale units (0.04 cm²),” stated Liu. “This efficiency gap, combined with costly and complex methods involving hot injection and ligand exchange, made commercial-scale CQD photovoltaics almost impractical. The efficiency gap, along with costly methods, has made commercial-scale CQD photovoltaics impractical.”

The first goal of the latest work by Liu and his colleagues was to facilitate the long run growth of PVs based mostly on quantum dots, enabling the low-cost manufacturing of large-area and environment friendly photo voltaic cells. In an effort to fulfill this objective, they launched a brand new ink engineering strategy that might help the manufacturing of CQD movies.

“To fabricate large-area conductive quantum dot films, these particles need to be uniformly and tightly stacked while maintaining their individual states to preserve quantum effects,” defined Liu. “Any inconsistency in size or stacking can lead to energy loss, negatively impacting semiconductor performance. This presents a delicate balance between quantum dot stacking and ligand design.”

Standard approaches to create CQDs depend on sizzling injection strategies to supply quantum dots wrapped in long-chain insulating ligands, adopted by a ligand alternate to shorter chains that enhances a movie’s conductivity. These approaches are each costly and complicated, thus they’re troublesome to copy on a big scale.

“Ligand exchange processes increase both complexity and material costs, while also causing aggregation and morphological defects, making it difficult to achieve uniformity over large areas,” stated Liu. “In contrast, our approach uses a direct synthesis (DS) technique to prepare CQD inks.”

The brand new ink engineering methodology devised by Liu and his colleagues allows the synthesis of ion-capped CQDs instantly in a polar solvent, thus eliminating the necessity for advanced ligand alternate processes. Utilizing their strategy, the researchers had been capable of print carefully packed conductive CQD movies in a single step.

“To minimize aggregation and fusion, we control the chemical environment of the ink, utilizing a solution chemistry engineering (SCE) strategy for precise tuning of ionic configurations and functionality,” stated Liu. “The simplified quantum dot technology and improved ink stability result in stable CQD inks with fewer defects, enabling the large-scale fabrication of quantum dot thin films and photovoltaic devices, all at a cost of less than $0.06/Wp.”

Shi, Liu and their colleagues examined their proposed strategy in a collection of exams and confirmed that it resulted within the manufacturing of extremely secure quantum dot inks. As well as, they uncovered a hyperlink between surface-dominated and irreversible quantum dot interactions and the defects current in printed CQD movies, in addition to the efficiency of large-area photo voltaic cells based mostly on these movies.

“Our efforts led to the creation of the first large-area CQD solar module with a certified power conversion efficiency (PCE) exceeding 10%, marking a significant step forward toward the commercialization of CQD-based photovoltaics,” stated Liu.

“In addition, we achieved a highly efficient small-area solar cell with a PCE of 13.40%, setting a new benchmark for CQD technology. These advances are crucial as they address the scalability and cost challenges that have long limited the widespread use of CQD solar cells.”

This latest examine may quickly contribute to the event of low-cost, large-area and extremely performing CQD-based photo voltaic cells and different optoelectronic units, corresponding to near-infrared sensors or instruments for area exploration.

As a part of their subsequent research, Liu and his colleagues plan to additional refine the inks produced utilizing their strategy, as this might end in photo voltaic cells with even higher efficiencies, whereas additionally extending their doable real-world functions.

“We will explore adapting the technology for various quantum dots, including low-toxicity variants, and flexible electronics,” added Liu. “Moreover, we’ll examine their use in fields corresponding to short-wave infrared (SWIR) imager—important parts for advancing reasonably priced AI applied sciences like autonomous automobiles, sensible robots, and industrial automation.

“Ultimately, our goal is to scale this technology for commercial production, reducing both costs and the environmental impact of quantum dot electronics.”

© 2025 Science X Community