Zong-Liang Tseng

Overcoming the Intrinsic Difference between Hydrophilic CH3NH3PbI3 and Hydrophobic C60 Thin Films to Improve the Photovoltaic Performance

Dimethylformamide/dimethyl sulfoxide solvent mixtures were used as the CH3NH3PbI3 (MAPbI3) precursor solvent in a one-step spin coating method to fabricate smooth and hydrophilic crystalline MAPbI3 thin films on top of hydrophobic carbon-60 (C60) thin film for highly efficient photovoltaics. The structural, optical, and excitonic characteristics of the resultant MAPbI3 thin films were analyzed using X-ray diffraction (XRD), atomic-force microscopy, absorbance spectroscopy, photoluminescence (PL) spectrometry, and nanosecond time-resolved PL. There was a trade-off between the crystallinity and surface roughness of the MAPbI3 thin films, which strongly influenced the device performance of MAPbI3-based photovoltaics. The high power conversion efficiency (PCE) of 17.55% was achieved by improving the wettability of MAPbI3 precursor solutions on top of the C60 thin films. In addition, it was predicted that the fill factor and PCE could be further improved by increasing the crystallinity of the MAPbI3 thin film while keeping it smooth.

Effect of Different CH 3 NH 3 PbI 3 Morphologies on Photovoltaic Properties of Perovskite Solar Cells

In this study, the perovskite layers were prepared by two-step wet process with different CH3NH3I (MAI) concentrations. The cell structure was glass/FTO/TiO2-mesoporous/CH3NH3PbI3 (MAPbI3)/spiro-OMeTAD/Ag. The MAPbI3 perovskite films were prepared using high and low MAI concentrations in a two-step process. The perovskite films were optimized at different spin coating speed and different annealing temperatures to enhance the power conversion efficiency (PCE) of perovskite solar cells. The PCE of the resulting device based on the different perovskite morphologies was discussed. The PCE of the best cell was up to 17.42%, open circuit voltage of 0.97xa0V, short current density of 24.06xa0mA/cm2, and fill factor of 0.747.

Improved Performance of Perovskite Light-Emitting Diodes by Quantum Confinement Effect in Perovskite Nanocrystals

In this study, we demonstrate an easy and reliable solution-processed technique using an extra adductive in the perovskite precursor solution. Using this method, a dense and uniform morphology with full surface coverage and highly fluorescent films with nanoscale crystal grains can be obtained. The high exciton binding energy in the resulting films employing octylammonium bromide (OAB) adductives proved that high fluorescence originated from the quantum confinement effect. The corresponding perovskite light-emitting diodes (PeLEDs) that were based on this technique also exhibited excellent device performance.

Preparation and Characteristics of MAPbBr3 Perovskite Quantum Dots on NiOx Film and Application for High Transparent Solar Cells

In this work, a MAPbBr3 quantum dot (QD-MAPbBr3) layer was prepared by a simple and rapid method. Octylammonium bromide (OABr) gives the MAPbBr3 better exciton binding energy, good surface morphology, and stability. To form a nanocrystalline thin film on indium tin oxide (ITO) glass, the QD-MAPbBr3 film was coated by a spin-coating method in a nitrogen-filled glove box and the NiOx film was used as an adhesive layer and hole transport layer. The highest transmittance of MAPbBr3 on NiOx/ITO glass was around 75% at 700 nm. This study also reported a high transparent and perovskite bulk-free ITO/NiOx/QD-MAPbBr3/C60/Ag solar cell where the NiOx, QD-MAPbBr3, and C60 were used as a hole transport layer, active layer, and electron transport layer, respectively.