An all-inkjet-printed flexible UV photodetector

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Flexible photodetectors are crucial for emerging optoelectronic applications.
• Developing cost-effective and scalable fabrication methods for high-performance devices remains a challenge.

Purpose of the Study:

• To propose and demonstrate a novel concept for all-inkjet-printed flexible photodetectors using zinc oxide (ZnO) nanocrystals.
• To investigate the influence of post-treatment methods (UV irradiation and thermal annealing) on device performance.

Main Methods:

• Inkjet printing of ZnO nanocrystal films.
• Post-treatment of films using UV light irradiation and high-temperature annealing.
• Characterization of photodetector performance, including responsivity and on/off ratio.
• Evaluation of device flexibility and durability through bending tests.

Main Results:

• UV-treated ZnO nanocrystal photodetectors achieved a high responsivity of 0.14 A W⁻¹ and an on/off ratio exceeding 10³.
• Performance of UV-treated devices surpassed that of thermally treated devices.
• The high performance is attributed to band-edge modulation and Schottky barriers, leading to low dark current and fast response.
• The photodetectors maintained performance after 500 bending cycles, indicating excellent flexibility and durability.

Conclusions:

• All-inkjet-printed flexible photodetectors based on ZnO nanocrystals offer high performance.
• UV post-treatment is a superior method for enhancing photodetector characteristics compared to thermal annealing.
• These printable devices pave the way for low-cost, solution-processed, flexible, and large-area integrated optoelectronic sensor circuitry.