Patterned structures ofin situsize controlled CdS nanocrystals in a polymer matrix under UV irradiation

Abstract

A method of in situ formation of patterns of size controlled CdS nanocrystals in a polymer matrix by pulsed UV irradiation is presented. The films consist of Cd thiolate precursors with different carbon chain lengths embedded in TOPAS polymer matrices. Under UV irradiation the precursors are photolyzed, driving to the formation of CdS nanocrystals in the quantum size regime, with size and concentration defined by the number of incident UV pulses, while the host polymer remains macroscopically/microscopically unaffected. The emission of the formed nanocomposite materials strongly depends on the dimensions of the CdS nanocrystals, thus, their growth at the different phases of the irradiation is monitored using spatially resolved photoluminescence by means of a confocal microscope. X-ray diffraction measurements verified the existence of the CdS nanocrystals, and defined their crystal structure for all the studied cases. The results are reinforced by transmission electron microscopy. It is proved that the selection of the precursor determines the efficiency of the procedure, and the quality of the formed nanocrystals. Moreover it is demonstrated that there is the possibility of laser induced formation of well-defined patterns of CdS nanocrystals, opening up new perspectives in the development of nanodevices.

One‐Pot Hybrid SnO2/Poly(methyl methacrylate) Nanocomposite Formation through Pulsed Laser Irradiation

“…For this reason, this unconventional synthetic methodology has paved the way for the achievement of various hybrids by simply tuning the organic environments in which the inorganic fillers will grow. Nevertheless, reports dealing with the formation of NPs induced by laser light mainly refer to chalcogenide‐based semiconductor materials (CdS, ZnS), transition metals, and lately ZnO NPs . To date, SnO 2 in situ synthesis in a polymer matrix through irradiation has not been presented.…”

“…Recently,the in situ synthesis of NPs triggered by laser irradiation, rather than the aforementioned chemical approach, has gained much more attention compared with other nanocomposite synthetic methods, [2,22,23] due to its capability to form well-dispersed, size-controlled NPs in specific areaso ft he polymeric matrix, in whicht he precursors are previously dispersed. For this reason,t his unconventional synthetic methodology has paved the way fort he achievement of various hybridsb y simply tuning the organic environments in which the inorganic fillers will grow.N evertheless, reports dealing with the formation of NPs inducedb yl aser light mainly refer to chalcogenide-based semiconductor materials (CdS, ZnS), [24][25][26] transition metals, [27][28][29][30][31] andl ately ZnO NPs. [32] To date, SnO 2 in situ synthesis in ap olymer matrix through irradiation has not been presented.U Vl ight and electron beam irradiation techniques have only been employed to grow SnO 2 NPso nn on-polymeric substrates, such as graphene oxide sheets, [21,33] whereas it would be highly desirable to develop new strategies fort he in situ formation of SnO 2 NPs in solid polymericf ilms.…”

Properties of Cadmium-(bis)dodecylthiolate and Polymeric Composites Based on It

“…The photoinduced plasmon nanocomposites with polymer matrices have been studied for a decade [3,4,5]. Recently, the creation and study of exciton-photoinduced nanocomposites have come to the forefront [7,8,9,10,11,12,13,14,15,16,17,18]. …”

“…It provides the ability to irradiate the chosen area, which is of interest for laser writing [10], and includes a great number of variable parameters, such as pulse repetition rate, wavelength, and laser fluence, for the processing optimization. The process of laser-induced semiconductor nanoparticle formation from cadmium-( bis )thiolates is described in [11,12,13,14]. The elucidation of the properties of the precursor is of fundamental importance.…”

CdS–Polymer Nanocomposites and Light‐Emitting Fibers by In Situ Electron‐Beam Synthesis and Lithography

“…This allows one to achieve light‐emitting nanocrystals only after the composite films have been deposited and eventually patterned by soft lithography or nanoimprinting methods, or, as an alternative, after fibers have been electrospun from the organic solution. Although in situ synthesis of nanoparticles is reported exploiting various routes for chemical,28, 29 thermal,30–35 or optical36 delivery of the energy needed for crystal nucleation and growth, most of the methods are unsuitable for high‐resolution patterning, since their ability to spatially limit the formation of nanocrystals within specific regions of sample is poor. The in situ synthesis of metal nanoparticles from a precursor containing the metal atoms has been attempted by electron‐beam irradiation, possibly relying on radical intermediates of the polymer, generated by bond scission 37, 38.…”