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Programmable Bipolar Photocurrents in Water-Templated Nanoporous Ferroelectrics for Filter-Free Spectral Recognition.
Chong Guo1,2, Weiqi Qian1,2, Huiyu Dan1,2
1Beijing Key Laboratory of High-Entropy Energy Materials and Devices, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, P. R. China.
Advanced Materials (Deerfield Beach, Fla.)
|March 20, 2026
Summary
Researchers developed nanoporous bismuth sodium titanate (BNT) films for bipolar electronic devices. These devices exhibit tunable, wavelength-dependent polarity reversal, enabling multistate logic and advanced sensing applications without external power.
Area of Science:
- Materials Science
- Nanotechnology
- Solid-State Physics
Background:
- Bipolar current devices offer advanced functionalities beyond binary electronics, but practical ferroelectric implementations are limited by unidirectional transport in zero-bias conditions.
- Existing ferroelectric devices often require external power for polarization switching, hindering versatile applications.
Purpose of the Study:
- To develop a novel fabrication strategy for nanoporous ferroelectric films enabling bipolar current devices.
- To investigate the potential of these devices for multistate logic, adaptive sensing, and reconfigurable circuits.
Main Methods:
- Fabrication of nanoporous bismuth sodium titanate (Bi0.5Na0.5TiO3 or BNT) films using a water-templated strategy.
- Characterization of film pore architecture and its tunability.
- Coupling of photovoltaic and thermoelectric effects to achieve wavelength-dependent polarity reversal.
Main Results:
- Achieved uniform and tunable pore architectures in BNT films.
- Demonstrated wavelength-dependent polarity reversal: positive photocurrents at 405 nm and negative photocurrents at 785 nm.
- Showcased programmable polarity-reversal thresholds via pore density, overcoming intrinsic unipolarity.
- Integrated devices capable of simultaneously discriminating optical wavelength and intensity through polarity-encoded outputs.
Conclusions:
- The water-templated fabrication strategy successfully created nanoporous BNT films for advanced electronic devices.
- The demonstrated wavelength-dependent polarity reversal and programmability pave the way for versatile zero-bias bipolar devices.
- These findings establish a foundation for biomimetic vision systems and ternary light-controlled logic.
