Energy-harvesting Light Source Arrays from Colloidal Double-Heterojunction Nanorods

With ever-increasing demand for more function and higher performance with reduced size and weight, fabrication of devices like smart phones and tablets are inevitably going to be more complex and more expensive. Their energy consumption, both in use and in manufacturing, will also increase accordingly. Recent advances to make semiconductors so small that their optical and electrical properties can be tuned by their size and shape are allowing simple ways to fabricate high-performance devices with high efficiencies and new capabilities.

For example, such tiny semiconductor materials may be made to not only emit but also sense and harvest light, a feature that can be exploited to develop devices such as displays with pixels that can generate its own power through scavenging ambient light. This project aims to address the important challenge of how electrons/charges can be efficiently placed in and out of these tunable semiconductor materials – a critical first step in any light emitting and photovoltaic devices.

The knowledge gained here will allow design and fabrication of high-performance LED pixel arrays with multiple capabilities such as solar energy harvesting and light sensing while simultaneously being a light source. Multi-faceted challenges to be tackled here provide ample educational and training opportunities for the students involved, helping them be better prepared to become leaders in interdisciplinary fields.

The PI is committed to building on the results of this project to enhance teaching and promote the benefits of emerging science and technologies.

Heterostructures of colloidal quantum dots provide opportunities to improve device performance and to usher in new capabilities. This project focuses on colloidal semiconductor nanorods that allow a double heterojunction to be formed on a quantum dot. These materials that the PI has recently developed have been shown to both emit and harvest light.

They can also be solution processed, opening up opportunities for compact, energy-efficient multifunctional device arrays on arbitrary substrates that can pave new paths to next generation of display, lighting, communication, and related technologies. Incorporating these materials into electronic/optoelectronic devices requires the understanding of how interfacing materials, such as charge transport layers, affect carrier injection, extraction, separation, and recombination.

Through a combination of studies on carrier dynamics and device physics, this project aims to elucidate how different electron and hole transport layers affect electroluminescence and photocurrent generation. The results of these efforts will guide the development of optimum interfaces for designing the next generation of electronic/optoelectronics devices with multiple functionality, especially those that can reduce energy consumption both in use and in manufacturing.

The research efforts of this project will also help to create new lectures, experiments for undergraduate laboratory courses, and demonstration materials that will enhance classroom teaching and promote nanoscience and energy-efficient technologies.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.