An Ultrasensitive Fluorescent Paper-Based CO₂ Sensor

Abstract

We demonstrate a versatile and easily fabricated paper-based CO2 sensor. The sensor consists of a specially designed fluorescent color-shift chromophore infused into standard filter paper. The emission color of the resulting fluorescent paper changes upon exposure to CO2 due to the formation of carbonic acid, which underlies the sensing mechanism. By using a ratiometric method, the undesirable effects of photobleaching can be eliminated, leading to a stable and repeatable sensor performance. These multiuse sensors have a response time on the order of 1 min and feature low detection limits for a paper-based CO2 gas sensor, suggesting possible low-cost applications in smart buildings or other facilities in which CO2 levels are required to be continuously monitored.

Paper Sensors Based on Fluorescence Changes of Carbon Nanodots for Optical Detection of Nanomaterials

“…In addition, the aforementioned protocols are based on solutions, making practical applications difficult. To this end, paper sensors are considered more practical for real life applications, since they are more easily handled and operated and, finally, can be incorporated in other protection devices [19,[29][30][31][32][33].…”

Hospitals and Laboratories on Paper-Based Sensors: A Mini Review

“…There is indeed a concern that most environmental inspection assays could not meet outdoor onsite detection due to the requirements of complicated instruments and a relative long detection time [ 73 ]. With properties of low cost, easy operation, great portability, and easy disposal, paper-based sensors were found reliable to detect carbon dioxide [ 33 ], airborne particulate [ 74 ], volatile organic compounds [ 75 ] in the air, heavy metals [ 76 ], phosphates [ 77 ], inorganic element ions [ 78 , 79 , 80 ], nitrite [ 81 ], and nicotine [ 82 ] in the water.…”

“…The detection of CO 2 is an essential prerequisite for humans to reasonably adapt to the evolution of nature and a requirement to protect the environment. Wang and coworkers designed a paper-based sensor for CO 2 detection with high accuracy based on the fluorescence assay, in which the fluorescence peak position shifted after the absorption of CO 2 with a detection limit of 5.7 ppm [ 33 ].…”

PEI-Functionalized Carbon Nanotube Thin Film Sensor for CO2 Gas Detection at Room Temperature

“…Carbon dioxide is a colorless and odorless gas, contributing to the greenhouse effect; it is a major cause of global warming [ 1 , 2 , 3 , 4 ]. Hence, reliable and low-cost CO 2 gas sensing is of great significance.…”