Study of zinc sulphide quantum dots | |
| Author | Warad, Hemant C. |
| Call Number | AIT Thesis no.ME-05-07 |
| Subject(s) | Quantum dots Zinc sulphide |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Advanced Technologies |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ME-05-07 |
| Abstract | Zinc sulphide based phosphor materials have attracted a great deal of interest because of the wide variety of applications ranging from conventional fluorescent lighting to cathode ray tubes, field emission displays, biological labeling etc. Because of stability, tunablility and higher efficiency, luminescent nanomaterials or quantum dots (QDs) is becoming a potential candidate to replace existing biological labels and drawing more attention of researchers. A novel method for the synthesis of colloidally stable ZnS:Mn2+ was studied, where homogenous solutions of zinc and manganese salts were co-precipitated in aqueous sodium sulphide. The optical absorption spectra shows that these ZnS:Mn2+ nanoparticles have an absorption edge at ~ 265 nm and glows with an orange red luminescence (~ 590 nm) corresponding to Mn2 + luminescent center. Based on Ostwald ripening and surface passivation we discuss a mechanism for the formation of ZnS:Mn2+ nanoparticles. These colloidally stable nanoparticles were sterically stabilized using a unique biopolymer 'chitosan', which shows a very high degree of polycrystallinity. These nanoparticles consists of primary particles that are around 30-40 nm in diameter, each consisting crystallites that was calculated from Debye Scherrer equation to be at around 2.65 nm. Copper doped ZnS were also synthesized which show green luminescence at ~ 480 nm. |
| Year | 2005 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ME-05-07 |
| Type | Thesis |
| School | School of Advanced Technologies (SAT) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Microelectronics (ME) |
| Chairperson(s) | Dutta, Joydeep; |
| Examination Committee(s) | Rakshit, Sudip K. ;Chanchana Thanachayanont; |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2005 |