Sri Lankan Journal of Physics, Volume 5, March 2004.

Semi classical chaos in a 2-D exactly solvable system
A. Nanayakkara
Institute of Fundamental Studies, Hanthana Road, Kandy

Sri Lankan Journal of Physics, Volume 5, March 2004.

Employing NiO as a hole collector in solid-state dye-sensitized solar cell
J. Bandara* and H. C. Weerasinghe
Institute of Fundamental Studies, Hantana Road, Kandy, Sri Lanka.

A solid-state dye sensitized solar cells (DSSC) comprising of p-type NiO thin layer on TiO2 was fabricated in which the dye is adsorbed on the p-type oxide and the thin NiO layer acts as a hole collector as well as a barrier for charge recombination. DSSC with NiO coated TiO2 electrode with Ru-dye delivers Isc = 0.15 mA and Voc = 480 mV. It was shown that the p-type oxide materials could be successfully used to construct DSSC and the plausible charge transfer mechanism is discussed.

Sri Lankan Journal of Physics, Volume 5, March 2004.

Spray painted nano structured TiO2 electrodes for solid-state dye sensitized photocells
G. K. R. Senadeera

Novel spray-pyrolysis (SPY), nano-structured TiO2 electrodes were prepared in the aim of developing cost-effective alternative route to the photoelectrodes for solid-state dye sensitized solar cells (SSDSC). Physical properties and photoresponses of these SPY electrodes were compared with the TiO2 electrodes prepared by the typical "doctor blade" (DB) technique. Enhanced necking of the TiO2 crystallites with higher porosity and larger surface area were observed in the SPY electrodes than in DB electrodes. Two sets of RuL(SCN)2 (L = 4,4'-dicarboxy-2,2'-bipyridyl) dye sensitized solid-state solar cells were constructed. One with DB and the other with SPY electrodes comprising CuI as hole transporting material. Preliminary studies showed that the photocells comprised with SPY electrodes have three fold higher overall efficiencies than that of the cells made up of DB electrodes under the same conditions. Improved necking between the TiO2 crystallites might be the reasons for this enhancement.

Sri Lankan Journal of Physics, Volume 5, March 2004.

Efficient solid-state dye sensitized solar cells fabricated on a compact Ti)2 barrier layer preventing short-circuit current
J. Bandara and H. C. Weerasingha

A dye sensitized solid-state solar cell (DSSC) was fabricated consisting of a dense TiO2 (D) and a nanoporous TiO2 (P) layers. The dense TiO2 layer of the DSSC type TiO2(D)/TiO2(P)/Dye/CuI prevents the short circuit problem, which normally encounter in DSSC while the poor dye adsorption of the dense TiO2 film is compensated using a porous TiO2 layer. The dense TiO2 film provides the opportunity of optimizing the performance of the second porous layer and the overall cell performance. i.e. TiO2(D)/Dye/CuI solar cell delivers Isc = 1.20 mA and Voc = 345 mV while solar cell consisting of a porous TiO2 layer on the dense TiO2 layer (TiO2(D)/TiO2(P)/Dye/CuI) delivers Isc = 6 mA and Voc = 500 mV.