Effect of dye concentration on the band gap of PVA turmeric composite film

Department of Physics, Ramakrishna Mission Residential College (Autonomous), Narendrapur,
Kolkata-700 103, India
Department of Electronics, Behala College, Behala, Kolkata-700 060, India
Condensed Matter Physics Research Centre, Department of Physics, Jadavpur University, Kolkata-700 032, India
E-mail: nb_manik@yahoo.com
Manuscript received online 02 December 2020, accepted 29 December 2020

In this work we have prepared and compared the performances of turmeric dye based herbal diodes for different dye concentrations.
The diodes are prepared by sandwiching turmeric dye layer in between the Cu and Al electrode. The Cu and Al electrodes are considered as anode and cathode terminals. We have measured forward and reverse biased I-V characteristic.Asymmetric nature in current voltage (I-V) relation confirms the diode characteristics of the devices. We have also measured the rectification ratio. We have also investigated the variation of current with temperature (I-T) to test the semiconducting properties of the devices. We have observed the I-T curve and found that current increases with temperature. Data is fitted to estimate the energy of the band gap of the diode. Band gap of the diode varies with the concentration of dye. Value of the band gap decreases with increasing the dye concentration. In our experiment the maximum and minimum value of the band gap is 3.36 eV and 2.82 eV for 5% and 20% concentration of the dye solution. We have also estimated ideality factor of three cells. The findings of this work are important to develop herbal dye based electronic device.