Navaphun Kayunkid

Growth and characterizations of tin doped zinc-phthalocyanine prepared by thermal co-evaporation in high vacuum as a nanomaterial

This research is related to the growth and characterizations of the novel hybrid nanomaterial, tin doped zinc-phthalocyanine thin films (Sn-doped ZnPC), grown by thermal co-evaporation. The concentration of Sn in hybrid films was controlled by adjusting the deposition rate between Sn and ZnPc. The hybrid films were characterized by atomic force microscopy and UV–visible spectroscopy to reveal the physical and optical properties of hybrid films. Moreover, the electrical properties, e.g., carrier mobility and carrier concentration, of the indium tin oxide (ITO)/Sn-doped ZnPc/aluminium (Al) devices were extracted from the current–voltage and capacitance–voltage characteristics. Furthermore, X-ray photoelectron spectroscopy and Raman spectroscopy was employed to explore the chemical interaction taking place in doped films. Sn doping into ZnPc changes the films specific properties, e.g., morphology, crystalline packing, absorption spectra, and conductivity. Moreover, no chemical bond is formed between Sn and ZnPc, and Sn dopants are formed as metal clusters covered by derivative oxide (SnOx) embedded in the Sn-doped ZnPc film.

Study on Optical and Electrical Properties of Bismuth-Doped Nickel-Phthalocyanine Thin Films

The objective of this work is to investigate the optical and electrical properties of bismuth-doped nickel-phthalocyanine thin films (Bi-doped NiPc). The doped films were prepared by thermal co-evaporation as a function of Bi concentration. The amount of Bi in NiPc was controlled via different deposition rates between metal dopant and organic host. The optical properties of the hybrid films were characterized by spectroscopic techniques. Furthermore, the electrical properties e.g. charge carrier concentration and carrier mobility of Al/Bi-doped-NiPc/ITO devices were characterized by current-voltage and capacitance-voltage measurements. The results of optical properties suggest that the crystalline packing of NiPc molecules in all preparation conditions is a combination of α-phase (majority) and β-phase (minority). However, the evolution of β-phase NiPc is observed with the increase of metal doping concentration. Raman spectroscopic results reveal that there is no chemical bond taken place between Bi and NiPc. In addition, with increasing dopant concentration, electrical properties present the enhancement of conducting current of hybrid devices as result from the increment of both charge carrier concentration and charge carrier mobility.

Study of Optical and Electrical Properties of Tin-Doped Magnesium Phthalocyanine Thin Films Grown by Thermal Co-Evaporation

The aim of this work is to investigate specific properties of tin-doped magnesium phthalocyanine (Sn-doped MgPc) thin films grown by thermal co-evaporation. Morphological, optical and chemical properties of the doped-films were characterized by atomic force microscopy (AFM), UV-Visible spectroscopy and X-ray photoelectron spectroscopy (XPS). Furthermore, electrical properties of ITO/Sn-doped-MgPc/Al devices such as carrier mobility and carrier concentration were extracted from current-voltage and capacitance-voltage measurements. Morphology of the doped films shows strong dependence on the existence of Sn in the doped films as clearly observed by changing of features of the film surface e.g. surface grain size and roughness. Optical absorption spectra of all conditions provide regular three dominant beta-phase peaks at 352, 640 and 691 nm corresponding to absorption from B-band and Q-band, respectively. The electrical properties obtained from ITO/Sn-doped MgPc/Al device suggest that the enhancement of the current flow in the doped device is a result from the increase of both carrier mobility and carrier concentration. Moreover, photoelectron analysis reveals two formations of Sn dopant in MgPc those are tin metal and derivative of tin oxide.

Improvement of Efficiency of Polymer-Zinc Oxide Hybrid Solar Cells Prepared by Rapid Convective Deposition

The aim of this research is to study improvement of power conversion efficiency (PCE) of organic-inorganic hybrid bulk heterostructure solar cell prepared by rapid convective deposition as a function of concentration of zinc oxide additive. The structure of hybrid solar cell used in this research is ITO/ZnO/P3HT:PC70BM:ZnO(nanoparticles)/MoO3/Au. By adding 5 mg/ml of ZnO nanoparticles in the active layer (P3HT:PC70BM), the PCE was increased from 0.46 to 1.09%. In order to reveal the origin of improving efficiency, surface morphology and optical properties of active layers were investigated by atomic force microscopy (AFM) and UV-Visible spectroscopy, respectively. The results clearly indicate that the enhancement of solar cell efficiency results from (i) the proper phase sepharation of electron donor and acceptor in the active layer and (ii) the better absorption of the active layer. This research work introduces an alternative way to improve solar cell efficiency by adding ZnO into active layer.