We use cookies to improve your experience and for marketing. Read our cookie policy or manage cookies.
Search across reports, market insights, and blog stories.
Researchers at the National University of Singapore have created an ultra-thin TOPCon solar cell that uses polysilicon passivated contacts on both sides, a design known as a biPoly solar cell. The device was built using low-pressure chemical vapor deposition, according to a study published in Progress in Photovoltaics.
The champion cell, measuring just 80 mm thick, reached an efficiency of 19.7% and an open-circuit voltage of 719 mV. It also demonstrated strong passivation, good optical performance, and noticeable mechanical flexibility. The team noted that the ultra-thin design could be suitable for applications such as building-integrated photovoltaics, indoor low-light energy harvesting, wearable electronics, portable power supplies, and solar quadcopters.
Fabrication started with M2-sized Czochralski silicon wafers that were thinned from 180 mm to 80 mm using a stress-driven etching process. The researchers applied standard RCA cleaning, a hydrofluoric acid dip, and rear-side protection with PECVD silicon nitride. Front-side texturing with potassium hydroxide formed pyramidal light-trapping structures. A full-area doped poly-Si layer was deposited on both sides via LPCVD, and selective patterning kept poly-Si only beneath metal contacts to reduce optical losses. A thin low-temperature oxide layer was grown, followed by PECVD SiNx deposition. Rear contacts were opened by laser contact opening, enabling screen-printed aluminum metallization, while front-side silver contacts were printed over the selective poly-Si regions. Final co-firing at 740 C completed the device.
Using quasi-steady-state photoconductance and photoluminescence measurements, the scientists found that the champion cell achieved an efficiency-to-thickness ratio of 0.25% per mm and a fill factor exceeding 83%. The research lead stated that the favorable performance came from optimized thermal treatment of the poly-Si layers, which improves dopant activation and interface quality, reducing recombination losses.
The cell is currently at the lab-scale research stage and is not ready for commercial production. Further work is needed on large-area fabrication, manufacturing-line compatibility, long-term stability validation, and flexible packaging optimization. The research lead noted that the proposed cell uses fully silicon-compatible fabrication processes with no additional high-cost materials, and its manufacturing cost is almost comparable to conventional silicon solar cells, suggesting low-cost industrialization potential. The study presented a quantitative evaluation of the interplay between surface passivation quality, optical engineering, and mechanical stability in ultra-thin silicon solar cells, though further optimization is required for contact resistivity, thermal stability, and long-term reliability under cyclic mechanical deformation.
Making Data-Driven Decisions to Grow Your Business
A Quick Overview of Market Performance
Understanding the Current State of The Market and its Prospects
Finding New Products to Diversify Your Business
Choosing the Best Countries to Establish Your Sustainable Supply Chain
Choosing the Best Countries to Boost Your Export
The Latest Trends and Insights into The Industry
The Largest Import Supplying Countries
The Largest Destinations for Exports
The Largest Producers on The Market and Their Profiles
The Largest Markets And Their Profiles
Instant access. No credit card needed.
Online access to 2M+ reports, dashboards, and tables. Trusted by Fortune 500 teams.
IndexBox, Inc.
2093 Philadelphia Pike #1441
Claymont, DE 19703, USA
Contact us
© 2026 IndexBox, Inc

source