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Multi-stacked hybrid graphene and quantum dot films for high response photodetection

用于高响应光电检测的多层混合石墨烯和量子点薄膜

基本信息

批准号：
1710472
负责人：
Oscar Vazquez-Mena
金额：
$ 30万
依托单位：
University of California-San Diego
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-01 至 2020-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710472&HistoricalAwards=false
关键词：
Multi stacked hybrid graphene quantum

项目摘要

Title: Hybrid graphene and quantum dot films for high response photodetectionAbstractNon-technical: Conversion of light to electricity is at the core of photodetection and photovoltaic devices that are critical for cameras, fast communications, information processing, biodetection, biomedical instruments, and energy harvesting. One of the main challenges for light detection is developing new technologies with low power consumption that can be thin and flexible to facilitate its use on wearable and portable devices. This project aims to develop a hybrid and ultrathin technology combining the strong light absorption of semiconducting nanoparticles (quantum dots) with the high electrical conductivity of one-atom thick carbon layers (graphene). The strategy for this project is to use quantum dots to collect light and generate electrical charges that will be collected by intercalated graphene layers for efficient charge transport. The intercalated graphene layers will serve as an efficient network of highly conductive paths for electrical charges inside the photodetector. Combining these nanomaterials would allow ultrathin photodetectors with high sensitivity and low power consumption that can be implemented on flexible and wearable devices. This project will also set a platform to train a new generation of students and engineers on the properties and applications of nanomaterials for optoelectronics and sunlight energy harvesting applications. Furthermore, this project will also help to disseminate new advances in nanotechnology for underrepresented communities, especially in high-schools in Hispanic communities in the region of Southern California.Technical: The goal for this project is to develop lead-sulfide quantum dot photodetectors with enhanced photoresponse using intercalated graphene layers for efficient current collection. It is a well-known restriction that for efficient current extraction with conventional top/bottom contacts, the thickness of the absorbing layers should not exceed the carrier diffusion length. If the films are thicker, then the photocarriers recombine before being collected by the top/bottom electrodes. This project aims to overcome this restriction by using intercalated layers with spacing shorter than the carrier diffusion length, allowing the efficient collection of photocharges before they recombine. This is an innovative strategy to break the limitation that diffusion length imposes on light absorbing layers and therefore boost the performance of optoelectronic devices. The first goal of the project will be to study the charge transfer dynamics and photoresponse at a graphene/quantum dot interface. Both materials have been largely studied, but their joint hybrid heterojunction is still largely unexplored. Since both are quantum confined systems with strong surface dependent behavior, the charge transfer can substantially differ from normal 'bulk' junctions. The technology to build the intercalated quantum dots and graphene devices will be developed based on low-temperature processing compatible with both nanomaterials, such as spin coating of quantum dots and graphene transfer. Integrating different nanomaterials in a single device can open a new route to develop high performing nanoscale devices combining their properties. Our analysis of the devices will be based on light absorption, photoresponsivity, and quantum efficiency measurements. The measurements will focus on studying the performance enhancement as function of the thickness of the absorbing layer and the spacing between graphene layers. This project has the potential to develop a new architecture for optoelectronic devices with superior carrier collection efficiency.

职务名称：用于高响应光电探测的石墨烯和量子点混合膜摘要非技术：光到电的转换是光电探测和光伏器件的核心，对于相机、快速通信、信息处理、生物检测、生物医学仪器和能量收集至关重要。光检测的主要挑战之一是开发具有低功耗的新技术，这些技术可以薄而灵活，以便于在可穿戴和便携式设备上使用。该项目旨在开发一种将半导体纳米颗粒（量子点）的强光吸收与单原子厚碳层（石墨烯）的高导电性相结合的混合和半导体技术。该项目的策略是使用量子点来收集光并产生电荷，这些电荷将被插层石墨烯层收集，以实现有效的电荷传输。插入的石墨烯层将作为光电探测器内部电荷的高导电路径的有效网络。结合这些纳米材料将允许具有高灵敏度和低功耗的光电探测器，可以在灵活和可穿戴设备上实现。该项目还将建立一个平台，培训新一代学生和工程师了解纳米材料在光电子和太阳能收集应用中的特性和应用。此外，该项目还将有助于为代表性不足的社区传播纳米技术的新进展，特别是在南加州地区西班牙裔社区的高中。技术：该项目的目标是开发具有增强光响应的硫化铅量子点光电探测器，使用插层石墨烯层进行有效的电流收集。众所周知的限制是，为了利用传统的顶/底接触进行有效的电流提取，吸收层的厚度不应超过载流子扩散长度。如果膜较厚，则光生载流子在被顶部/底部电极收集之前重新组合。该项目旨在通过使用间距小于载流子扩散长度的夹层来克服这一限制，从而在光电荷重新组合之前有效收集光电荷。这是一种创新的策略，可以打破漫射长度对光吸收层的限制，从而提高光电器件的性能。该项目的第一个目标是研究石墨烯/量子点界面的电荷转移动力学和光响应。这两种材料已经被大量研究，但它们的联合混合异质结仍然在很大程度上未被探索。由于两者都是具有强表面依赖行为的量子限制系统，因此电荷转移可以与正常的“体”结基本上不同。构建嵌入式量子点和石墨烯器件的技术将基于与两种纳米材料兼容的低温处理来开发，例如量子点的旋涂和石墨烯转移。将不同的纳米材料集成到一个器件中可以开辟一条新的途径，以开发结合其特性的高性能纳米器件。我们对器件的分析将基于光吸收、光响应和量子效率测量。测量将集中于研究作为吸收层的厚度和石墨烯层之间的间距的函数的性能增强。本计画有潜力发展出具有上级载子收集效率之光电元件新架构。