High-Performance Photodiodes Based on In-Situ Etched PbSe Colloidal Quantum Dots with Responses Extended to 2500 nm.
Ruiguang Chang1, Qiulei Xu1, Qiuyang Yin1
1Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials, Henan University, Kaifeng 475004, China.
Nano Letters
|November 28, 2024
Summary
Stable large-sized lead-selenide (PbSe) colloidal quantum dots (CQDs) were developed using chloride etching. This breakthrough significantly improves PbSe CQD photodiode performance beyond 2000 nm.
Area of Science:
- Materials Science
- Nanotechnology
- Optoelectronics
Background:
- Lead-selenide (PbSe) colloidal quantum dot (CQD) photodetectors exhibit limited performance beyond 2000 nm.
- Chemical instability of large-sized PbSe CQDs hinders their application in long-wavelength photodetection.
Purpose of the Study:
- To develop a novel method for stabilizing PbSe CQDs.
- To enhance the performance of PbSe CQD-based photodetectors for infrared applications.
Main Methods:
- In-situ etching of PbSe CQDs using chloride ions in a weak acidic solvent.
- Formation of a lead-chloride (-Pb-Cl) surface protection layer on PbSe CQDs.
- Fabrication and characterization of photodetectors using stabilized PbSe CQDs.
Main Results:
- The -Pb-Cl layer effectively passivates surface selenium atoms, preventing oxidation.
- Achieved a responsivity of 0.75 A/W at 2200 nm for the photodetectors.
- Demonstrated 0.15 V open circuit voltage and 100% internal quantum efficiency without photoconductive gain.
Conclusions:
- The chloride etching method provides a unique and effective approach to stabilize PbSe CQDs.
- The stabilized PbSe CQDs enable record-breaking performance for photodiodes operating beyond 2000 nm.
- This work paves the way for advanced infrared photodetector development.
