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Perovskite solar cells have developed rapidly in recent years as the third generation solar cells. In spite of the great improvement achieved, there still exist some issues such as undesired hysteresis and indispensable high temperature process. In this work, bulk heterojunction perovskite-phenyl-C 61 -butyric acid methyl ester solar cells have been prepared to diminish hysteresis using a facile two step spin-coating method. Furthermore, high quality tin oxide films are fabricated using pulse laser deposition technique at room temperature without any annealing procedure. The as fabricated tin oxide film is successfully applied in bulk heterojunction perovskite solar cells as a hole blocking layer. Bulk heterojunction devices based on room temperature tin oxide exhibit almost hysteresis-free characteristics with power conversion efficiency of 17.29% and 14.0% on rigid and flexible substrates, respectively. [ABSTRACT FROM AUTHOR]

Light-emitting diodes (LEDs) based on ZnO were fabricated on a p -Si substrate by using a pulsed laser deposition system. Significant electroluminescence (EL) improvement was demonstrated with the insertion of an HfO 2 electron blocking layer (EBL) in n -ZnO/ p -Si heterojunctions. Distinct near-band-edge emission at around 392 nm accompanying by a broadly strong visible emission was achieved when a proper thickness of HfO 2 EBL was used. Current-voltage and capacitance-voltage measurements confirmed that a proper thickness of the HfO 2 EBL can effectively balance the injection of electrons and holes, resulting in an increase of radiative recombination in the ZnO active layer and thus enhancing the EL performance of the devices. Five independent emissions corresponding to five different transition processes were proposed to clarify the EL origination of the n -ZnO/HfO 2 / p -Si heterojunction LEDs by Gaussian deconvolutions. It is hoped that results in this work should be helpful for the development of ZnO-based LEDs that can integrate ZnO with the Si planar technology. [ABSTRACT FROM AUTHOR]

Abstract: Efficient bulk-heterojunction (BHJ) polymer solar cells (PSCs) based on poly (3-hexylthiophene) (P3HT): indene-C60 bisadduct (ICBA) were fabricated with lithium fluoride (LiF) as electron collecting buffer layer and UV–ozone (UVO) treated molybdenum trioxide (MoO3) as hole collecting buffer layer. LiF is observed to be critical for the device performance, significantly enhancing the fill factor (FF) and the efficiency compared to the device without LiF layer. MoO3 layer is also critical to the device performance, efficiently extracting holes to prevent the exciton quenching and reducing the interfacial resistance because of alignment of energy band. After UVO treatment on MoO3 film, its surface morphology, transmittance and film quality can be improved, therefore, it is beneficial to the performance of the PSCs. The optimal thickness of MoO3 and UVO treatment time on MoO3 was 12nm and 15min, respectively. Based on these optimal parameters, a power conversion efficiency (PCE) of 6.43% was obtained under AM1.5G 100mW/cm2 illumination. [Copyright &y& Elsevier]