Bulk Heterojunction Organic Solar Cells, Solvents, Doped Performance Study

Energy problem has become a tough issue that needs to be solved in21stcentury.Solar energy has drawn a great concern from various countries for its characteristics ofinexhaustible supply. Solar cell is an effective method to change solar energy intoelectrical energy. Due to its advantages of mass production, being made on flexiblesubstrate, simple technique of device’s manufacture, low cost, being adjustable ofenergy band gap and no pollution, the polymer solar cell has become a research hotspot.To study how to increase the efficiency of the polymer bulk heterojunction solarcell is the focal point of solar cell’s practicality, and this is going to deeply study on thissubject.To increase the short circuit current and open circuit voltage is an effective way toraise the efficiency of solar cell. Based on the mature structure ofITO/PEDOT:PSS/MEH-PPV:PCBM/Bphen(10nm)/Ag and materials, we used twomethods to increase device’s short circuit current so as to increase the device’sefficiency: one is to use additive DIO, and the other is to add materials of high holemobility.The main research contents include:1. To use DIO as additive, make comparative experiments based on the structure ofMEH-PPV:PCBM so as to study its influence on polar cell’s performance. Then to makea couple of experiments using DIO of different consistency and to get the mostfavorable consistency.When using additive DIO, the most favorable consistency is20mg/ml, the device’sopen circuit voltage VOCis0.65V, the short circuit current JSCis8.74mA/cm2, the fillfactor EF is43%, and the efficiency PCE is2.44%. After using DIO, the short circuitcurrent is increased by54.9%, while the efficiency PCE55.4%.2. To add NPB to the active layer of MEH-PPV:PCBM so as to study its influenceon the device’s efficiency. Then to make a couple of experiments using NPB of differentproportion and to get the most favorable proportion. When adding NPB to the active layer, the most favorable proportion of NPB is15%, the device’s open circuit voltage VOCis0.72V, the short circuit current JSCis10.3mA/cm2, the fill factor EF is38%, and the efficiency PCE is2.79%. After usingNPB, the open circuit voltage is increased by54.9%, while the short circuit current33.4%and the efficiency PCE55.4%.3. To make experiments by combining the most favorable consistency of DIO andproportion of NPB and to get the most favorable device’s efficiency.When using additive DIO with consistency of20mg/ml and NPB with proportionof15%, the device’s open circuit voltage VOCis0.74V, the short circuit current JSCis10.84mA/cm2, the fill factor EF is38%, and the efficiency PCE is3.07%. The shortcircuit current is increased by48.8%, while the efficiency PCE73.4%.