Superior white electroluminescent devices using nitrogen-doped carbon dots/TiO2nanorods heterostructures

Poulomi Chakrabarty; Arup Ghorai; Sourabh Pal; Deepanjana Adak; Baidyanath Roy; Samit K Ray; Rabibrata Mukherjee

doi:10.1088/1361-6528/acfb08

Superior white electroluminescent devices using nitrogen-doped carbon dots/TiO₂nanorods heterostructures

Nanotechnology. 2023 Oct 13;35(1). doi: 10.1088/1361-6528/acfb08.

Authors

Poulomi Chakrabarty^{1

2}, Arup Ghorai¹, Sourabh Pal³, Deepanjana Adak⁴, Baidyanath Roy¹, Samit K Ray^{1

5}, Rabibrata Mukherjee^{1

2}

Affiliations

¹ School of Nanoscience and Technology, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.
² Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.
³ Advanced Technology Development Center, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.
⁴ Centre of Excellence for Green Energy and Sensor Systems, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, West Bengal, India.
⁵ Department of Physics, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.

PMID: 37725943
DOI: 10.1088/1361-6528/acfb08

Abstract

Nitrogen-doped carbon dots (NCDs), exhibiting strong yellow emission in aqueous solution and solid matrices, have been utilized for fabricating heterostructure white electroluminescence devices. These devices consist of nitrogen-doped carbon dots as an emissive layer sandwiched between an organic hole transport layer (PEDOT:PSS) and an array of rutile TiO₂nanorods, acting as an electron transport layer. Under an applied forward bias of 5 V, the device exhibits broadband electroluminescence covering the wavelength range of 390-900 nm, resulting in pure white light emission characteristics at room temperature. The result demonstrates the successful fabrication of all solution-processed, low-cost, eco-friendly NCDs-based LEDs with CIE (Commission Internationale d'Éclairage) coordinate of (0.31, 0.34) and color rendering index (CRI) > 90, which are close to ideal white light emission characteristics. The device functionalities are achieved based on defect-related NIR emission from TiO₂nanorods array and visible emission from nitrogen-doped carbon dots. This result paves a new opportunity to develop low-cost, solution-processed nitrogen-doped carbon dots based on warm White light emitting diodes with high CRI for large-area display and lighting applications.

Keywords: nitrogen-doped carbon dots; solution-processed; voltage-dependent; white light-emitting diodes.