Sains Malaysiana 41(4)(2012): 439-444

Penentuan Aras Jalur Tenaga Kompleks Tungsten Nitrosilditiolena

(Determination of Band Energy Levels for Tungsten Nitrosyldithiolene)

Mark Lee Wun Fui¹, Ng Kim Hang¹, Lorna Jeffery Minggu², Akrajas Ali Umar³ & Mohammad B. Kassim ^{1, 2} *

¹Pusat Pengajian Sains Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor D.E., Malaysia

²Institut Sel Fuel, Universiti Kebangsaan Malaysia

43600 UKM, Bangi, Selangor D.E., Malaysia

³Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN), Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E., Malaysia

Received: 29 June 2011 / Accepted: 20 October 2011

ABSTRACT

The chemical and physical properties of tungsten nitrosyldithiolene complexes with a general formulae of [WTp*(NO)(L)] where Tp* = tris(3,5-dimethylpyrazolyl)hidroborate and L = toluene 3,4-dithiolate (L1), 1,2-benzenedithiolate (L2), 3,6-dichloro-1,2-benzenedithiolate (L3), have been studied for application as a photosensitizer in an anode for photoelectrochemical cell. These complexes were synthesized and characterised by infrared (IR), ultraviolet-visible (UV-Vis) spectroscopy and CHNS micro elemental analysis. Cyclic voltammetry (CV) was used to determine their redox potentials and their band energies were calculated from the potentials obtained. All three complexes showed energy band gaps in the range of 1.59 – 1.63 eV. The calculated band gaps from CV analyses were comparable with the estimated values obtained from the UV-Vis absorption data. Based on the postulated band diagram, these complexes may be a potential photosensitizer to be used in the photoeletrodes for photoelectrochemical cells.

Keywords: Photoelectrochemical cell; photosensitizer; tungsten nitrosyldithiolene

ABSTRAK

Sifat-sifat kimia dan fizik kompleks tungsten nitrosilditiolena dengan formula am [WTp*(NO)(L)] dengan Tp* = tris(3,5- dimetilpirazolil)hidroborat dan L = toluena-3,4-ditiolat (L1), 1,2-benzenaditiolat (L2), 3,6-dikloro-1,2-benzenaditiolat (L3), telah dikaji untuk dijadikan pemeka foto bagi elektrod anod untuk sel fotoelektrokimia. Kompleks tungsten nitrosilditiolena disintesiskan dan diciri dengan menggunakan spektroskopi (IR) dan ultra-lembahyung dan cahaya nampak (UV-Vis) dan analisis mikro unsur CHNS. Teknik voltametri berkitar (CV) telah digunakan untuk menentukan keupayaan redoks kompleks dan seterusnya aras jalur tenaga telah ditentukan daripada data yang diperoleh. Ketiga-tiga kompleks menunjukkan jurang jalur tenaga dalam julat 1.59 – 1.63 eV. Jurang jalur tenaga yang dikira daripada analisis CV adalah bersepadan dengan anggaran daripada spektrum serapan elektronik kompleks. Berdasarkan gambar rajah jalur tenaga, ketiga-tiga kompleks dijangka mempunyai potensi untuk digunakan sebagai pemeka foto bagi fotoelektrod sel fotoelektrokimia.

Kata kunci: Pemeka foto; sel fotoelektrokimia; tungsten nitrosilditiolena

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*Corresponding author; email: mbkassim@ukm.my