Palestinian Conference on Graduate Students Research in Natural and Applied Sciences, At Birzeit University, Birzeit, Palestine

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Research Title: 
Modification of CuSe thin film electrodes prepared by electrodeposition: Enhancement of photoelectrochemical characteristics by controlling cooling rate and covering with polymer/metalloporphyrin
Rola Sultan Al-Kerm, Ahed Zyoud and, Hikmat S. Hilal
Birzeit University, Birzeit, Palestine
Fri, 2913-12-22
Research Abstract: 
CuSe thin films were prepared by electrodeposition technique on FTO/glass substrates. Different parameters were controlled to study and enhance the prepared films including: deposition time (5, 10 and15 min), annealing the prepared films at different temperatures (150, 250 and 350oC) under nitrogen for 1 hr, and cooling rate. The annealed films were cooled to room temperature using two methods either slow or fast cooling. Moreover, an electro-active matrix of tetra (-4-pyridyl porphyrinatomanganese) (ΙΙΙ) sulfate complex (MnP) inside commercial Poly Ethylene (PE) was used to cover the prepared CuSe films.
Effects of annealing temperature, cooling rate, deposition time, and covering with MnP-PE matrix on the film characteristics were investigated for different films using different techniques: AFM, PL spectra, electronic absorption spectra, together with photoelectrochemical parameters including: dark J-V plots, photo J-V plots, value of short-circuit current, open circuit potential and stability.
Different electrolytic solutions were used to find the system with the highest PEC conversion efficiency and stability. Effect of annealing time (1, 2 and 3 hrs) on the efficiency of the prepared thin films, annealed at 150oC, was studied after covering them with MnP-PE matrix.
AFM, electronic absorption spectra, photo J-V plots showed that the 15 min deposition time gave films with more uniform, smoother, more homogeneous surfaces, stronger electronic absorption, higher conversion efficiency and higher fill factor (2.9% and 42.95% respectively) than other counterparts. 
The 150oC annealing temperature followed by fast cooling was found to be the best annealing temperature, since it gave higher conversion efficiency and fill factor, more homogeneous surfaces, and better stability than other counterparts.
Covering the pre-annealed CuSe thin films enhanced PL and electronic absorption spectra, photo J-V plots, conversion efficiency, fill factor and stability. Moreover pre-annealing the covered CuSe films with MnP-PE matrix for 2 hrs gave highest conversion efficiency and fill factor (14.3%, 77.4%respectively).
Two different organic redox couples were used in the PEC measurement I2/KI and Fe (CP)2 /Fe(CP)2PF6. The Fe (CP)2 /Fe(CP)2PF6 redox couple gave higher conversion efficiency and fill factor than other counterparts
Different aqueous electrolytic solutions FeCl2/FeCl3, NaOH/S-2/Sx-2, K3Fe (CN)6/K4Fe(CN)6/ LiClO4, I2/KI on PEC characteristics of pre-annealed and covered CuSe thin film electrodes have been studied. K3Fe (CN)6/K4Fe(CN)6/ LiClO4 gave higher percentage conversion efficiency and fill factor than other counterparts.

This study has come out with a major finding and recommendation that is: Pre-annealing CuSe film electrodes at certain temperature (150oC) followed by coverage with suitable electroactive matrix MnP/PE significantly enhanced their physical properties and PEC characteristics.