2, Korea Institute of Science and Technology, Gyeonggi, , Korea (the Republic of)
Organic-inorganic perovskites have already exhibited an enormous potential for optoelectric devices, such as photovoltaics, light-emitting diodes and photodetectors, which can realize low-cost and large area devices with high performance. Especially, perovskites reveal effective light absorption and high charge carrier mobility which lead to exploiting sensitive and fast photodetectors for visual and chemical/biological image sensing. In previous researches, inorganic quantum dots (QDs) was applied to perovskite solar cell for effective energy alignment which improves charge transport. Herein, we demonstrate enhanced performance of solution-processed photodetectors composed of CH3NH3PbI3 perovskite films with CH3NH3PbX3(X=I, Br) QDs as a charge transport layer. Meanwhile, highly bright and stable CH3NH3PbX3 QDs are difficult to synthesize through currentligand-assisted reprecipitation(LARP) technique because of the organic solvent in the precursor and the difficulty of redispersion. We developa simple and highly reproducible synthesis method ofCH3NH3PbX3QDs by modified LARP technique. The advanced synthesis technique has process of precipitation of QDs by anti-solvent and surfactants are already dissolved in poor solvent instead of precursor.Introducing the QD transport layer controlled optical properties ontoperovskite films results in more improved photo response in the devices caused by enhanced near-field luminescence and plasmonic resonance. The QDs can also promote the transport of photon-generated carriers from the active layer to electrode. Combining the advantages of facile solution processability and high charge carrier mobility, introduction of the QDs based on novel synthesis is expected to replace commercial silicon with perovskite photodetection system.
 L. Hu, W. Wang, H. Liu, J. Peng, H. Cao, G. Shao, Z. Xia, W. Ma and J. Tang, J. Mater. Chem. A, 2015, 3, 515