Inverted Bulk Heterojunction (BHJ) Polymer (PCDTBT-PC70BM) Solar Photovoltaic Technology

Inverted Bulk heterojunctions (Ag/MoO3/PCDTBT-PC70BM/ZnO/ITO) Organic Solar cells, based on Organic (Polymer) materials is fabricated and characterized in this work. PCDTBT-PC70BM was synthesized by chloroform, chlorobenzene and o-dichlorobenzene (organic solvent). Surface morphology of ZnO and PCDTBT-PC70BM were studied. Bulk heterojunctions of active material are formed by the mixture of PCDTBT donor and PC70BM an acceptor in a random manner. For Sufficient transportation of charge carrier (electron and hole), hole transport (HT) and electron transport (ET) layers was deposited. ZnO is used as an ETM and synthesized by using Sol-Gel technique. MoO3 thin film deposited over the active material, enhances hole transformation because of band gap tuning with Ag and active materials. Absorbance and Photoluminescence spectra of polymer material with different organic solvents were studied and results were discussed in this work. o-dichlorobenzene enhance the absorption of PCDTBT/PC70BM. At 400 nm, 90% of sun light is absorbed, and 70% absorption is figure out in 500- 550nm wavelength. The Photo-luminescence of PCDTBT/PC70BM thin film in different organic solvents is ranging from 650nm to 750nm. At 700nm, 20% is shown for chloroform, 40% for chlorobenzene and highest 80% is achieved by o-dichlorobenzene. J-V value is obtained from a solar simulator which irradiates the sun spectrum 1.5 AM, for all the devices having cell area 0.045 cm2. For concentration (1:1) ratio in different organic solvents like chloroform, chlorobenzene and o-dichlorobenzene, (3.5, 4.2, and 5.8) %, PCE were obtained respectively.