■INTRODUCTION Many health care systems lack access to robust diagnostic equipment and therapeutic treatments.This is particularly problematic in less developed countries and in remote locations i.e.small rural areas ...■INTRODUCTION Many health care systems lack access to robust diagnostic equipment and therapeutic treatments.This is particularly problematic in less developed countries and in remote locations i.e.small rural areas or villages.Laboratories in developing countries are often sparsely distributed,under-resourced with access hindered by economical or geographical factors.1 Such circumstances make the management and control of disease outbreaks and pandemics e.g.Covid-19 very difficult and challenging.Therefore,there is a need for low cost and reliable point-of-care(POC)test systems that allow for rapid diagnosis of disease beyond laboratory settings.Reverse transcription polymerase chain reaction(RT-PCR)testing is still considered the“gold-standard”method for Covid-19 detection,however its reliance on precise and expensive thermal cyclers has restricted its use in resource limited settings and for POC applications.2−4 In addition,reports of false-negative results when the RT-PCR test was utilized for Covid-19 detection,further strengthens the case for the development of alternative test systems.展开更多
Metal oxide resistive gas sensors suffer from poor selectivity that restricts their practical applicability.Conventional sensor arrays are used to improve selectivity which increased the system complexity.Here,we have...Metal oxide resistive gas sensors suffer from poor selectivity that restricts their practical applicability.Conventional sensor arrays are used to improve selectivity which increased the system complexity.Here,we have proposed a novel NiO/ZnO-based p–n junction single-diode device for selective sensing of several volatile organic compounds(VOCs)simultaneously by tuning bias voltage.The operating voltage was varied between 3 and 5 volts to achieve selective sensing of 2-propanol(19.1 times for 95ppm with response and recovery times of 70 s and 55s respectively‚at 3 volts),toluene(20.1 times for 95 ppm with response and recovery times of 100 s and 60 s respectively,at 4 volts),and formaldehyde(11.2 times for 95 ppm with response and recovery times of 88 s and 54s respectively,at 5 volts).A probable mechanism of the tunable selectivity with operating bias voltage due to increase in surface carriers with increasing voltage was hence put forth.Thus,this device may play an important role to develop future selective multiple VOC sensor thereby replacing standard sensor arrays.展开更多
文摘■INTRODUCTION Many health care systems lack access to robust diagnostic equipment and therapeutic treatments.This is particularly problematic in less developed countries and in remote locations i.e.small rural areas or villages.Laboratories in developing countries are often sparsely distributed,under-resourced with access hindered by economical or geographical factors.1 Such circumstances make the management and control of disease outbreaks and pandemics e.g.Covid-19 very difficult and challenging.Therefore,there is a need for low cost and reliable point-of-care(POC)test systems that allow for rapid diagnosis of disease beyond laboratory settings.Reverse transcription polymerase chain reaction(RT-PCR)testing is still considered the“gold-standard”method for Covid-19 detection,however its reliance on precise and expensive thermal cyclers has restricted its use in resource limited settings and for POC applications.2−4 In addition,reports of false-negative results when the RT-PCR test was utilized for Covid-19 detection,further strengthens the case for the development of alternative test systems.
基金The authors would like to acknowledge Central Research Facility(CRF)of IIT Kharagpur for various characterization support of nanomaterial.S.S would like to acknowledge Department of Science and Technology(DST)for DST Women Scientist Scheme A(WOS-A)for the partial support of this work(project no.-SR/WOS-A/PM-100/2017(G))。
文摘Metal oxide resistive gas sensors suffer from poor selectivity that restricts their practical applicability.Conventional sensor arrays are used to improve selectivity which increased the system complexity.Here,we have proposed a novel NiO/ZnO-based p–n junction single-diode device for selective sensing of several volatile organic compounds(VOCs)simultaneously by tuning bias voltage.The operating voltage was varied between 3 and 5 volts to achieve selective sensing of 2-propanol(19.1 times for 95ppm with response and recovery times of 70 s and 55s respectively‚at 3 volts),toluene(20.1 times for 95 ppm with response and recovery times of 100 s and 60 s respectively,at 4 volts),and formaldehyde(11.2 times for 95 ppm with response and recovery times of 88 s and 54s respectively,at 5 volts).A probable mechanism of the tunable selectivity with operating bias voltage due to increase in surface carriers with increasing voltage was hence put forth.Thus,this device may play an important role to develop future selective multiple VOC sensor thereby replacing standard sensor arrays.
