Specialized LEDs efficiently emit and harvest light
Specialized LEDs efficiently emit and harvest light lead image
Colloidal quantum dots are opening paths for new optoelectronic and photovoltaic technologies. Emerging variants of these materials, such as double heterojunction nanorods (DHNRs), accelerate these advances through simultaneously enhancing the emission and harvesting of light.
Building on their previous research with DHNRs, Huang et al. presented an improved device that is more efficient at harvesting light. The researchers developed LEDs using a thin film of DHNRs treated with a solution of aromatic thiols.
“Through this work, we were able to develop a very simple approach of exchanging some of the insulating molecules with shorter, more conducting aromatic thiols to improve the photovoltaic efficiency by about a factor of two,” said author Moonsub Shim.
The resulting LEDs were characterized as light emitters as well as solar cells. The results suggested the enhanced charge separation helped improve their performance as solar cells.
“We had initiated this work thinking that we will simply improve electrical conductivity of the film of these materials, but it turned out that the key impact of the molecules we used was to help separate photogenerated charges,” Shim said. “We also noticed that the devices that were better LEDs also performed better as solar cells. This is especially exciting since we can now improve both functions simultaneously.”
The researchers envision their advances could be used in light sources that are also solar cells, such as electronic billboards and cell phone screens that can be powered by ambient light. They plan to continue optimizing the type and amount of molecules that passivate the surface of DHNRs, as well as improving device structure and loading of DHNRs.
Source: “Improving photovoltaic performance of light-responsive double- heterojunction nanorod light-emitting diodes,” by Conan Huang, Yiran Jiang, Gryphon A. Drake, Logan P. Keating, and Moonsub Shim, Journal of Chemical Physics (2023). The article can be accessed at https://doi.org/10.1063/5.0147782 .
This paper is part of the 40 Years of Colloidal Nanocrystals in JCP Collection, learn more here .
