Polarization-based colour tuning of mixed colloidal quantum-dot thin films using direct patterning.

Area of Science:

• Optoelectronics
• Photonics
• Materials Science

Background:

• Colloidal quantum dots (cQDs) offer high brightness and wide color gamuts for optoelectronic devices.
• Current thin-film device efficiencies are limited by optical losses, particularly into waveguide modes.
• Strategies to improve light outcoupling are crucial for advancing cQD-based technologies.

Purpose of the Study:

• To enhance light outcoupling efficiency in colloidal quantum-dot (cQD) thin films.
• To achieve bright, linearly polarized emission from cQD thin films.
• To demonstrate active color tuning using polarization in cQD devices.

Main Methods:

• Fabrication of linear gratings on cQD thin films using a template-stripping direct-patterning strategy.
• Utilizing Bragg scattering from surface gratings to promote optical outcoupling.
• Patterning gratings with varying periodicities and orientations on mixed-color cQD films.

Main Results:

• Significant enhancement of optical outcoupling from cQD thin films.
• Generation of bright emission with a high degree of linear polarization.
• Demonstration of polarization-based active color tuning of the emitted light.

Conclusions:

• Direct-patterning of linear gratings is an effective method to improve light outcoupling in cQD thin films.
• The fabricated gratings enable efficient Bragg scattering, leading to polarized emission.
• This approach provides a pathway for tunable color emission in advanced optoelectronic applications.