Facet‐Oriented Coupling Enables Fast and Sensitive Colloidal Quantum Dot Photodetectors

Margherita Biondi(University of Toronto), Min‐Jae Choi(University of Toronto), Zhibo Wang(University of Toronto), Mingyang Wei(University of Toronto), Seungjin Lee(University of Toronto), Hitarth Choubisa(University of Toronto), Laxmi Kishore Sagar(University of Toronto), Bin Sun(University of Toronto), Se‐Woong Baek(Korea University), Bin Chen(University of Toronto), Petar Todorović́(University of Toronto), Amin Morteza Najarian(University of Toronto), Armin Sedighian Rasouli(University of Toronto), Dae‐Hyun Nam(Daegu Gyeongbuk Institute of Science and Technology), Maral Vafaie(University of Toronto), Yuguang Li(University of Toronto), Koen Bertens(University of Toronto), Sjoerd Hoogland(University of Toronto), Oleksandr Voznyy(University of Toronto), F. Pelayo Garcı́a de Arquer(University of Toronto), Edward H. Sargent(University of Toronto)
Advanced Materials
July 10, 2021
10.1002/adma.202101056
Cited by 79Open Access
Full Text

Abstract

Abstract Charge carrier transport in colloidal quantum dot (CQD) solids is strongly influenced by coupling among CQDs. The shape of as‐synthesized CQDs results in random orientational relationships among facets in CQD solids, and this limits the CQD coupling strength and the resultant performance of optoelectronic devices. Here, colloidal‐phase reconstruction of CQD surfaces, which improves facet alignment in CQD solids, is reported. This strategy enables control over CQD faceting and allows demonstration of enhanced coupling in CQD solids. The approach utilizes post‐synthetic resurfacing and unites surface passivation and colloidal stability with a propensity for dots to couple via (100):(100) facets, enabling increased hole mobility. Experimentally, the CQD solids exhibit a 10× increase in measured hole mobility compared to control CQD solids, and enable photodiodes (PDs) exhibiting 70% external quantum efficiency (vs 45% for control devices) and specific detectivity, D * > 10 12 Jones, each at 1550 nm. The photodetectors feature a 7 ns response time for a 0.01 mm 2 area—the fastest reported for solution‐processed short‐wavelength infrared PDs.

Related Papers

No related papers found

Powered by citation graph analysis