Organic-inorganic hybrid perovskite materials have been recently emerged as a promising cost- and energy efficient light absorber material for photovoltaic applications. Unfortunately, perovskite solar cells have a problem with decreacement of power conversion efficiency due to degradation in the air. To detect the reason of degradation on perovskite solar cells, we exposed deposited CH3NH3PbI3 and HC(NH2)2PbI3 films to the O2 or (H2O+N2) atmosphere condition. Analysis of the film revealed that the large energy band gap was shown due to influence of H2O molecule in CH3NH3PbI3 and HC(NH2)2PbI3. In (H2O+N2) atmosphere conditions, the existence of CH3NH3I and HC(NH2)2I molecule has found to affect the morphology, absorption and as well as crystalline diffraction peak. The resultant perovskite crystalline structure was degraded by H2O molecules in the air exposure condition.
Perovskite (CH3NH3PbI3) solar cell (PSC) have been recently emerged as a promising cost and energy efficient light absorber material for photovoltaic applications. In this paper, we fabricated planar heterojunction (PHJ) perovskite solar cells using chemical bath deposited low temperature titanium oxide (TiOx) compact layer as an electron collection layer. The devices modified by fullerene (C60) with the thickness of 7nm show very significant improvement in photovoltaic performances compared to without modified devices leading to efficiencies as high as 9.0%. This is due to enhanced electrons more efficiently at the CH3NH3PbI3 /compact-TiOx interface from the C60 leading to improved photocurrent densities and fill factors.
We report a simple method to achieve efficient nanostructured organic photovoltaics via patterning copper iodide (CuI) nano-rod template on indium tin oxide. The CuI nano-rod sheet was fabricated by glancing angle deposition method. The strong interfacial interaction between zinc phthalocyanine (ZnPc) and CuI leads to the formation of nano-pillar arrays with lying-down crystalline order, which greatly improve absorption efficiency and surface roughness for exciton dissociation. Optimized ZnPc/C60 bilayer cell has a power conversion efficiency of 4.0 ± 0.1%, which is about three-fold larger than that of conventional planar cell.
In addition, we also reported the new type of nano-structured template based on organic semiconductor. As the template material, diindenoperylene (DIP) was introduced into bilayer photovoltaic cells using based on tetraphenyldibenzoperifl anthene (DBP) and C60. While the basic molecular structure of DIP is similar to that of DBP, DIP shows higher crystallinity than DBP one. We obtained power conversion efficiency of 5.2% and high fill factor of 0.72 due to high crystallinity of DIP nano-structured template.